JP3760980B2 - Map display device, recording medium, and map display method - Google Patents

Description

ただし、ｋ₁ ＝ｂ・Ｌ ｋ₂ ＝ａ・Ｌ ｋ₃ ＝（ｂ−ａ）
により求められる。また、Ｘ座標値ｓｘは、台形の下辺の長さｂから台形の上下辺の長さの差（ｂ−ａ）にＹ座標値を乗じて台形の縦の長さＬで除した値（ｂ−ａ）ｓｙ／Ｌを減じ、矩形のＸ方向の長さｇに対するＸ座標値の比を乗じて、つまり、
〔数２〕

ただし、ｋ₄ ＝ｇ ｋ₅ ＝ｂ ｋ₆ ＝（ｂ−ａ）／Ｌ
により求められる。
【００３０】
以下に、まずＹ座標の変換について説明する。図９（Ａ）において斜めの直線の式は、
〔数３〕
Ｙ＝Ｌ・Ｘ／２ｇ＋Ｌ／２
で表される。そこで、この斜めの直線が変換後も直線として保たれるように、且つＸ座標が等分割となるように変換後の地図を仮定し、この直線ともう１つの地図データの２次元座標におけるＸ座標値が一定の直線により図９（Ｂ）に示すメッシュの三角形を考える。これらは相似となるので、それぞれの三角形の辺の長さの比率を考える。まず、三角形の縦の長さの比が（Ｌ−ｓｙ）：ｓｙとなる。これに対し、三角形の底辺の長さは、上辺がａ−Ｘａ／ｇ、下辺がｂ＋Ｘｂ／ｇとなる。したがって、相似三角形の辺の長さの比が等しいことから、
〔数４〕
（Ｌ−ｓｙ）：ｓｙ＝（ａ−Ｘａ／ｇ）：（ｂ＋Ｘｂ／ｇ）
となる。この〔数４〕と上記〔数３〕からＸを消去すると、〔数１〕が求められる。また、上辺ａ、下辺ｂに変換される固定値ｇのＸ座標値を縦の長さｓｙに対応させると、（ｂ−ａ）ｓｙ／Ｌとなるから、任意のＸ座標値では、ｇとＸとの比を乗じることにより〔数２〕が求められる。
【００３１】
次に、ビル等の立体的な建造物について同様に台形変換パラメータを用いた２次元的な座標変換により立体的に表示する場合について説明する。例えばビルは、階数ｎのデータを有するときには、平均的な階高ｈを階数ｎに乗じてｎ×ｈ＝Ｈとして高さを求め、また、階数ｎではなく、タワーのように全体としての高さＨのデータを有するときにはその高さＨに基づき座標変換を行う。Ｙ座標値ｓｙにおける高さＨのＹ座標値ｓｙ′への座標変換は、２次元平面上で変換されたＸ座標値ｓｘとＹ座標値ｓｙの上に例えば〔数５〕を用いてＹ座標値の加算値ΔＹを求めることにより行うことができる。
【００３２】
〔数５〕
ｓｙ′＝ｓｙ＋ΔＹ
ｂ−ａ ｓｙ
Ｙ＝（１−─────・────）Ｈ＝（１−ｋ₇ ｓｙ）Ｈ
ｂ Ｌ
ただし、ｋ₇ ＝（ｂ−ａ）／ｂ・Ｌ＝ｋ₃ ／ｋ₁
したがって、図１０（Ａ）に示すように（ｓｘ１，ｓｙ１）の地点で高さＨの建造物の頂点座標値は、
〔数６〕
（ｓｘ１，ｓｙ１＋ΔＹ）＝｛ｓｘ１，ｓｙ１＋（１−ｋ₇ ｓｙ）Ｈ｝
となり、このようにして変換した各座標を線で結び、枠内を所定の色で塗りつぶし、奥の方から順にこの処理を行って重ね書きすることにより、図１０（Ｂ）に示すような表示を行うことができる。
【００３３】
上記のように台形変換パラメータとして、ａ，ｂ，ｇ，Ｌから、或いはこれらからｋ₁ 〜ｋ₇ を算出して、これらと座標値（Ｘ、Ｙ）、高さｈから立体的な建造物についての座標変換を簡単な加減乗除の計算により実行することができる。したがって、ビルに限らず、家屋や橋等立体的な建造物についても全て同様にして立体的に描画でき、例えば図１２で後述するように建造物のデータとして、建造物の形状を表す座標列（ポリゴンデータ）と、建造物の階数情報（又は建造物の高さ）からなる場合、２次元座標からなる各点及び建造物の階数情報から上記のように座標変換して、現在位置から所定距離以内の建造物だけ描画することにより更に描画レスポンスの向上を図ることができ、現在位置が移動するに伴って、その現在位置から所定距離以内の建造物のみを立体表示することも簡単に行うことができる。
【００３４】
具体的には、現在位置検出装置により検出された現在位置と各建造物との距離を算出し、その距離が所定距離以内か否かを判断する。その判断結果が所定距離以内であれば上記座標変換を行って立体表示する。ここで、距離を算出する際、現在位置と建造物の中心点との距離でもよいし、現在位置と建造物の形状を表す座標列のうち１つの座標との距離でもよい。目的地までの案内において、ユーザが建造物の形状を参考にしながら運転できるようにするには、目的地までの経路沿いにのみ建造物を建てるようにしたり、現在位置から所定距離以内でかつ経路沿い、その他上記の表示態様を組み合わせてもよい。また、現在位置から所定距離以内でかつ現在位置からの距離に応じて建造物の高さＨを増減させてもよい。つまり、現在位置近傍では建造物の高さＨをそのまま用い、現在位置から遠ざかるに従い、高さＨの値を小さくする。また、建造物の表示を行う場合、所定の高さ以上の建造物や車両の現在位置より進行方向前方に位置する建造物のみ立体表示し、所定の高さに達しない建造物や車両の現在位置より進行方向後方に位置する建造物は同一の高さで立体表示もしくは立体表示ではなく平面表示したり、立体交差等においては正確な表示を行えるようにするために、高さの低いものから描画するなど、描画する建造物の順序や選択は自由に組み合わせ可能であることはいうまでもない。
【００３５】
また、上記〔数２〕では、Ｐ（Ｘ，Ｙ）からＰ′（Ｘ，ｓｙ）とした後、そのｓｙを用いてＰ１（ｓｘ，ｓｙ）を求めたが、ｓｙを用いずＸ，Ｙの座標値からｓｘを求めてもよい。例えば、〔数２〕において、ｓｙにＹを用いｓｘ′を求めると、Ｐ（Ｘ，Ｙ）は、図９（Ｂ）に示すＰ１′（ｓｘ′，ｓｙ）に変換されて台形から膨らむので、座標変換した結果はお椀形状になる。
【００３６】
次に、本発明の地図表示装置を備えた車両用ナビゲーション装置で使用されるデータの構成例を説明する。図１１は情報記憶装置に格納された主要なデータファイルの構成例を示す図、図１２は建造物データの構造の例を示す図である。
【００３７】
案内道路データファイルは、図１１（Ａ）に示すように、道路数ｎのそれぞれに対して、道路番号、長さ、道路属性データ、形状データのアドレス、サイズおよび案内データのアドレス、サイズの各データからなり、経路探索部により経路を算出し経路案内を行うために必要なデータとして格納される。道路番号は、分岐点間の道路毎に方向（往路、復路）別に設定されている。道路属性データは、道路案内補助情報データであり、形状データは、図１１（Ｂ）に示すように、各道路の複数のノード（節）で分割したとき、ノード数ｍのそれぞれに対して東経、北緯からなる座標データを有している。案内データは、図１１（Ｃ）に示すように、交差点（または分岐点）名称、信号機データ、ランドマークデータ、注意点データ、道路名称データ、道路名称音声データ、行き先データのアドレス、サイズの各データからなる。
【００３８】
情報記憶装置３に記憶する建造物データの構造は、例えば図１２（Ａ）に示すように建造物のデータ数Ｎの次にＮ個の各建造物のデータが記憶される。そして、各建造物のデータは、建造物の名称、番地（住所）、種別、建造物の形状、高さ、詳細の各情報からなる。名称は、ビルであればそのビル名、個人の家屋であればその居住者名、施設であればその施設名、道路であれば「中央通り」、「国道１号」のように道路種別や通り名であり、番地（住所）は、その建造物の番地である。建造物の形状は、形状を表す座標数ｎとその座標値（ｘ₀ ，ｙ₀ ）、（ｘ₁ ，ｙ₁ ）、………、（ｘ_n-1 ，ｙ_n-1 ）であり、種別は、一般の家屋、マンション、オフィスビル、公共施設、道路、公園等の情報である。高さは、階数や高さ（ｍ）の情報である。高さを階数で格納している場合には、テーブルを用いて高さ（ｍ）の情報に変換する。そして詳細は、例えばテナントビルであれば各入居者に関する情報であり、名称数ｍと各テナントについて、名称、電話番号、部屋番号、分類（レストラン、コンビニ、……等の業種、事業内容）に関する情報である。したがって、図１２（Ｂ）に示すように建造物の形状に関する情報として座標値を順に読み出して線で結び描画し表示することによって、例えばビルや家屋の平面形状や公園の地形を出力することができる。
【００３９】
なお、本発明は、上記実施の形態に限定されるものではなく、種々の変形が可能である。例えば上記実施の形態では、２次元座標を台形変換による遠近地図の２次元座標上に座標変換したが、他の従来から行われている座標変換を行う遠近地図にも同様に適用してもよい。また、ユーザにより階数の指定があった場合にはその階数以上の高さの建造物を選択して表示し、その指定がない場合にはデフォルトとして３階以上の建造物を選択し、その総数が最小閾値から最大閾値までを表示率１００％から上限値の５０％まで徐々に表示率を下げ、最大閾値を越えると一律上限値の表示率５０％として建造物を表示したが、ユーザにより階数の指定があった場合にも同様に表示率を調整してもよい。
【００４０】
さらには、表示数の閾値を１つだけにして、描画範囲内の建造物データ数が閾値までは全数とし、閾値を越える場合には一定の割合の表示数となるようにしたり、描画範囲内の建造物データ数が閾値までは表示数の割合を減らし、閾値を越える場合には一定の割合の表示数となるようにしてもよいし、いずれの場合においても、表示数の上限値を設定してもよい。また、これらの表示数の制限を、画面全体に一律ではなく、画面を上下に２分割あるいは３分割など複数に表示領域を分割し、それぞれの領域毎に指定階数、最小閾値、最大閾値、表示率の上限値、表示数の上限値を設定してもよい。このようにすることにより、例えば遠方になるほど選択する建造物の階数を高くし、また、表示数を少なくするなど遠近に応じてその領域毎に表示する建造物を選択することができる。また、建造物の高さとして階数ではなく高さそのもの（ｍ）で選択するように構成し、あるいは床面積や容積で選択するように構成してもよい。
【００４１】
また、上記実施の形態では、高さデータとして階数を記憶し、ユーザが入力した階数以上の建造物を選択したが、建造物の高さとして、階数ではなく高さそのもの（ｍ）で選択するように構成してもよい。このような場合には、建造物の高さはデータ（階数）に予め決められている１階の階高を乗じて求め、求めた建造物の高さとユーザが入力した高さを比較し選択するようにしてもよい。また、建造物の高さデータとして高さそのもの（ｍ）を記憶するようにしてもよいことはいうまでもない。
【００４２】
また、上記実施の形態では、ユーザが指定した高さ以上の建造物を選択したり、あるいはシステムが自動的に設定した高さ以上の建造物を選択して表示し、遠近表示においては、画面の上方になるほど建造物は低く表示される。そのため、座標変換された後の建造物を比較すると、図３と図１０から分かるように、相対的に画面の上方の低い建造物が表示され、画面下方の高い建造物か消去されることが起こることにより、ユーザは地図に違和感を持つ。そこで、座標変換した後の建造物の高さに対して、ユーザが入力した高さ以上の建造物を抽出したり、あるいは自動的に建造物を選択する場合には、座標変換した後の建造物の高さから平均値を求め、その平均値以上の建造物（勿論、座標変換後の高さに対して）を選択し表示するようにしてもよい。なお、自動的に建造物を選択する場合の表示する高さの基準は、予め決められている高さ、例えば５ｍでもよい。
【００４３】
【発明の効果】
以上の説明から明らかなように、本発明によれば、建造物を立体的に表示する地図表示装置において、２次元座標及び高さ情報を有する建造物データを格納する情報記憶手段と、該情報記憶手段に格納された建造物データの２次元座標及び高さ情報に基づいて建造物を遠近地図上に立体的に描画する描画制御手段と、該描画制御手段により描画された建造物を表示する表示手段とを備え、描画制御手段は、描画範囲における建造物データの数を検出して建造物の表示数を決定する表示数決定手段を有し、高さ情報に基づいて高い方から決定した表示数の建造物データを選択して建造物を遠近地図上に立体的に描画するので、建造物を立体的に表示しても地図が煩雑になることなく、ユーザにとって目立つ建造物を選択して表示することができる。
【００４４】
さらに、表示数決定手段は、表示数の閾値を有し、描画範囲内の建造物データ数が閾値までは全数とし、閾値を越える場合には一定の割合の表示数としたり、描画範囲内の建造物データ数が閾値までは表示数の割合を減らし、閾値を越える場合には一定の割合の表示数とし、あるいは表示数の閾値として最小閾値と最大閾値を有し、建造物データの数が最小閾値までは全数とし、最小閾値から最大閾値まで表示数の割合を減らし最大閾値を越える場合には一定の表示割合とするので、ユーザが目立つ建造物を容易に見つけ出すことができ、車両の現在位置をカーソル等で表示した場合に、地図画面の建造物から現在位置の大まかな位置を容易に得ることができる。
【図面の簡単な説明】
【図１】 本発明に係る地図表示装置の実施の形態を示す図である。
【図２】 表示する建造物データの登録処理の例を示す図である。
【図３】 建造物の描画処理の例を示す図である。
【図４】 建造物の描画処理における表示建造物設定処理の例を示す図である。
【図５】 建造物の表示数を制御するパラメータの設定例を説明するための図である。
【図６】 表示モードの選択画面の例を示す図である。
【図７】 各設定による３Ｄビル表示のイメージの例を示す図である。
【図８】 各設定による３Ｄビル表示の画面の例を示す図である。
【図９】 台形座標変換アルゴリズムを説明するための図である。
【図１０】 建造物の高さデータの座標変換アルゴリズムを説明するための図である。
【図１１】 情報記憶装置に格納された主要なデータファイルの構成例を示す図である。
【図１２】 建造物データの構造の例を示す図である。
【符号の説明】
１…入力装置、２…現在位置検出装置、３…情報記憶装置、４…中央処理装置、５…情報送受信装置、６…出力装置、１１…遠近表示制御部、１２…座標変換部、１３…変換パラメータ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a map display device, a recording medium, and a map display method for three-dimensionally displaying a building.
[0002]
[Prior art and problems to be solved by the invention]
Vehicle navigation devices that have route search and route guidance functions expand the road map around the current position of the vehicle and the device that displays the driving image in three dimensions so that the information on the direction of travel can be provided in an easy-to-understand manner. Devices for displaying road maps using a so-called bird's-eye view display method have been proposed (Japanese Patent Laid-Open Nos. 1-263688, 8-136270, 8-160853, and 8- No. 166249, JP-A-8-292720, JP-A-9-127861, etc.).
[0003]
Some devices that have been proposed in the past, for example, provide a window display area on a part of the bird's-eye view to display a wide area map, and further display the range of the bird's-eye view with a frame, which is a disadvantage of the bird's-eye view. Is no longer difficult to grasp, and the wide area of the road map is not clear. In addition, in some cases, by displaying a flat map or a bird's-eye view close to the flat map within a predetermined range on the upper side of the display area, it is possible to eliminate the difficulty of understanding the road conditions in the distance and accurately grasp the road information in the distance I can do it.
[0004]
However, in the bird's-eye view as described above, and when a building is to be displayed in a three-dimensional manner by, for example, a building attribute information display system (see Japanese Patent Laid-Open No. 4-268593), the building is displayed from a plane map. The amount of shape information on the map increases as much as it is displayed three-dimensionally, and the map becomes complicated to the eye. In other words, the map itself becomes difficult to see and the visibility deteriorates. In addition, when displaying a bird's-eye view, there is a problem that if the coordinate conversion is performed from the two-dimensional map data using a trigonometric function, the processing becomes complicated and time-consuming. If there is a lot of map data, the problem becomes more prominent. When the coordinate calculation is performed three-dimensionally using the height data, there is a problem that the processing is further delayed.
[0005]
[Means for Solving the Problems]
The present invention solves the above-described problem, and can easily display a building on a perspective map in a three-dimensional manner so that the position can be easily confirmed.
[0006]
  For this purpose, the present invention provides a map display device for stereoscopically displaying a building, information storage means for storing building data having two-dimensional coordinates and height information, and building data stored in the information storage means. A drawing control means for three-dimensionally drawing the building on the perspective map based on the two-dimensional coordinates and the height information, and a display means for displaying the building drawn by the drawing control means. The means has a display number determining means for detecting the number of the building data in the drawing range to determine the display number of the building, and the building having the display number determined from the higher one based on the height information. It is characterized by selecting data and drawing a building three-dimensionally on a perspective map.
[0007]
  Further, the display number determining means has a display number threshold value, wherein the number of building data in the drawing range is the total number up to the threshold value, and when it exceeds the threshold value, the display number is a fixed ratio. The display number determining means has a display number threshold value, and reduces the display number ratio until the number of building data in the drawing range reaches the threshold value. The display number determination means has a minimum threshold value and a maximum threshold value as display value threshold values, the total number of the building data is the minimum threshold value, and the ratio of the display number from the minimum threshold value to the maximum threshold value is When the maximum threshold is decreased, the display ratio is fixed.
[0008]
  Further, a computer-readable recording medium for a map display device that displays a building three-dimensionally includes building data having two-dimensional coordinates and height information,ComputerThe number of building data in the drawing rangeBased on the two-dimensional coordinatesDisplay number determination to detect and determine the display number of buildingsmeansThe building data of the determined display number is selected from the higher one based on the height information of the building data, and the building is three-dimensionally drawn on the perspective map based on the two-dimensional coordinates and the height information. Drawing controlmeansAnd the drawing controlmeansDisplay that displays the building drawn by 3D on the perspective map in three dimensionsmeansIs recorded with a program for realizing the above.
[0009]
  A map display method for three-dimensionally displaying a building stores building data having two-dimensional coordinates and height information in an information storage means,By computerThe number of building data stored in the information storage means in the drawing rangeBased on the two-dimensional coordinatesThe number of buildings displayed is determined by detection, the building data of the determined number of displays is selected from the higher one based on the height information of the building data, and the two-dimensional coordinates and the height information are selected. The building is three-dimensionally drawn on a perspective map, and the drawn building is three-dimensionally displayed on the perspective map.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a map display device according to the present invention. Display conditions, coordinate conversion parameters, and route guidance when a map is developed from map data having two-dimensional coordinates and height information are displayed. An input device 1 for inputting information on the current position, a current position detection device 2 for detecting information on the current position of the host vehicle, map data having two-dimensional coordinates and height information, navigation data necessary for route calculation, route guidance Necessary display / speech guidance data, information storage device 3 in which a program (application and / or OS) for displaying map, route calculation, guidance, etc. is recorded, map display processing as navigation data processing means , Route search processing, display / voice guidance processing necessary for route guidance, and central processing unit 4 for controlling the entire system, information on vehicle travel For example, an information transmission / reception device 5 that transmits / receives road information, traffic information, detects information about the current position of the vehicle, and transmits / receives information about the current position, a display or speaker that outputs information about route guidance, etc. Output device 6. That is, an example in which the map display device according to the present invention is applied to a navigation device is shown.
[0011]
The input device 1 has a function of selecting a map and inputting a destination, or instructing the central processing device 4 to perform navigation processing at the driver's will. As means for realizing the function, a remote controller such as a touch switch or a jog dial for inputting a destination by a telephone number or coordinates on a map or requesting route guidance can be used. Further, the present invention includes a device for performing dialogue by voice input, and functions as a voice input device. A recording card reader for reading data recorded on an IC card or a magnetic card can also be added. In addition, an information center that stores data necessary for navigation and provides information via a communication line at the request of the driver, and a portable type having data such as map data, destination data, simple maps, and building shape maps A data communication device for exchanging data with an information source such as an electronic device can be added.
[0012]
The current position detection device 2 obtains the current position information of the vehicle using a satellite navigation system (GPS), an absolute direction sensor that detects the traveling direction of the vehicle in an absolute direction by using, for example, geomagnetism, a vehicle For example, a steering sensor, a relative azimuth sensor that detects the relative azimuth by using a gyro sensor, for example, a distance sensor that detects the travel distance of the vehicle from the rotational speed of the wheel.
[0013]
The information storage device 3 is an external storage device that stores a navigation program and data, and includes, for example, a CD-ROM. The program includes a program for performing processing such as route search, a processing program shown in the flowchart described in the present embodiment, a display output control necessary for route guidance, a program for performing interactive guidance by voice input, and necessary for it A program for performing voice output control necessary for voice guidance and necessary data for voice guidance are stored. Stored data includes map data, search data, guidance data, map matching data, destination data, registration point data, road data, intersection image data such as intersections, genre-specific data, landmark data, and other files. Thus, all the data necessary for the navigation device is stored. The map data is divided into blocks for each predetermined unit and stored in a rectangular shape. The present invention can also be applied to a type in which only data is stored in a CD-ROM and the program is stored in a central processing unit. Here, the information storage device may be not only a CD-ROM but also an optical disk such as a DVD-ROM, a magnetic disk such as a floppy disk, and a magneto-optical disk such as MO.
[0014]
The central processing unit 4 includes a perspective display control unit 11 that performs control for displaying a building three-dimensionally, a coordinate conversion unit 12 that performs coordinate conversion for displaying a map including the building as a perspective map, and perspective. A drawing control unit 14 including conversion parameters 13 for converting coordinates to a map; a CPU that executes various arithmetic processes; a flash memory that reads and stores a program from a CD-ROM of the information storage device 3; ROM that stores a program (program reading means) for performing program check and update processing of flash memory, point coordinates of a set destination, road name code No. The RAM is a RAM that temporarily stores searched route guidance information and the like and data being processed. In addition, although not shown in the drawings, a frame memory for storing data to be displayed on an output device such as a display, interactive processing by voice input from the input device 1, or a voice output control signal from the CPU A speech processor that synthesizes speech, phrases, single sentences, sounds, etc. read out from the information storage device 3 based on the above, converts them into analog signals and outputs them to a speaker, and communication that exchanges input and output data by communication The interface and the sensor input interface for taking in the sensor signal of the current position detection device 2 and the clock for entering the date and time in the internal diagnosis information are provided. Note that a program for performing the above-described update processing may be stored in an external storage device.
[0015]
All programs and other programs for executing navigation may be stored in a CD-ROM which is an external storage medium, or a part or all of these programs may be stored in the ROM 42 on the main body side. Various navigation functions are realized by inputting data and programs stored in the external storage medium as external signals to the central processing unit of the navigation apparatus main body and performing arithmetic processing.
[0016]
In the navigation device, a relatively large-capacity flash memory for reading a program from a CD-ROM of an external storage device as described above, and a small-capacity ROM storing a program (program reading means) for starting up a CD are provided. Built in. The flash memory is a non-volatile storage means that retains stored information even when the power is turned off. Then, as a CD start-up process, a program of ROM that is a program reading means is activated and the program stored in the flash memory is checked, and the CD management information of the CD-ROM of the information storage device 3 is read. The program loading process (update process) is performed based on this information and the state of the flash memory.
[0017]
The information transmitter / receiver 5 is a GPS receiver that acquires information using a satellite navigation system (GPS), a VICS information receiver that acquires information using FM multiplex broadcasting, radio wave beacons, optical beacons, etc. By using a telephone, a personal computer, etc., it is composed of an information center (for example, ATIS) and a data transmitting / receiving device for bidirectionally communicating information with other vehicles.
[0018]
The output device 6 has a function of outputting guidance information by voice and / or a screen when the driver needs it, and printing out data subjected to navigation processing by the central processing unit 4. As means for this, a memory for expanding and rendering data processed by the central processing unit 4 and data stored in the information storage unit 3 on a screen, a display for displaying image data rendered in the memory, and the central processing unit 4 A printer that prints out the data processed in step 1 and data stored in the information storage device 3, a speaker that outputs route guidance by voice, and the like.
[0019]
The display is composed of a simple liquid crystal display or the like, and is expanded and drawn based on map display data and guide data processed by the central processing unit 4 and drawn intersection enlarged view screen, destination name, time, distance, progress Display directional arrows, etc. The image data to be displayed on the display is binary image data (bitmap data), using a communication line that uses map display data and guide data processed by the central processing unit 4 in serial communication, etc. The communication line is also received, developed in the memory in the output device 6 and rendered, and then the designated display range is displayed on the display screen.
[0020]
This display is provided in an instrument panel in the vicinity of the driver's seat, and the driver can check the current location of the host vehicle and obtain information on the route from now on by looking at the display. Although not shown in the figure, a tablet including a touch panel, a touch screen, etc. may be used on the display screen, and the point input, road input, etc. can be performed by touching the screen or tracing the screen. Good.
[0021]
In the present invention, when a building is three-dimensionally displayed on a perspective map based on building data having two-dimensional coordinates and height information, the display number is appropriately controlled according to the height information of the building. This prevents the map from becoming complicated and difficult to see. FIG. 2 is a diagram showing an example of registration processing of building data to be displayed, FIG. 3 is a diagram showing an example of building drawing processing, and FIG. 4 is a diagram showing an example of display building setting processing in building drawing processing. FIG. 5 is a diagram for explaining an example of setting parameters for controlling the number of displayed buildings.
[0022]
When a building is displayed three-dimensionally based on the building data, first, as shown in FIG. 2, it is first determined whether or not there is a user-designated floor number as a display condition (step S11). If there is no floor, the building data of the lowest floor N, for example, 3 floors or higher is automatically registered (step S12). Is registered (step S13). Here, a drawing range is set based on the current location of the vehicle or the current location of the cursor when the map is scrolled by the user, and a two-dimensional coordinate building located in the drawing range is registered. Next, a drawing process is performed using the registered building data as a display process target.
[0023]
In the drawing process, as shown in FIG. 3, first, it is determined whether or not there is a user-designated floor (step S14). If there is no user-designated floor, the displayed building setting is set for the registered building data. (Step S15), if there is a floor specified by the user, the registered building data is sorted by the distance from the current location (step S16), and drawing is performed from a distant building (step S17). . In addition, you may draw from the building in front.
[0024]
In the display building setting process, as shown in FIG. 4, it is first determined whether or not the total number of registered building data is smaller than the minimum threshold value (step S21). If the total number is equal to or greater than the minimum threshold, the registered building data is sorted by height (step S22), and it is further determined whether the total is smaller than the maximum threshold (step S23). Is smaller than the maximum threshold value, the number of displays is calculated at a rate corresponding to the total number (step S24). If the total number is equal to or greater than the maximum threshold value, half of the total number is set as the display number (step S25). Registration is performed from the sorted higher data (step S26).
[0025]
  As mentioned above, if there is a floor specified by the user, all buildings with higher floors are displayed, and if there is no floor specified by the user, calculation is based on the minimum threshold, maximum threshold, and upper limit of the display rate. Display the number of buildings displayed on the map. Therefore, as shown in FIG. 5, the display rate is 100% until the total number reaches the minimum threshold, and when the total number exceeds the maximum threshold, the display rate is set to 50% of the upper limit, and the total number is between the minimum threshold and the maximum threshold. This is to reduce the display rate from 100% to 50%, and to reduce the display rate linearly. The minimum threshold and the maximum threshold may be determined for each scale, for example, 5 and 40 when the scale is 1/1000, 10 and 100 when the scale is 1/2500, or only the minimum threshold is determined for each scale. The maximum threshold value may be determined to be n times the minimum threshold value, 8 times or 10 times in the above example. By doing so, the display rate α when the target building total number m is from the maximum threshold max and the minimum threshold min,
      α = 1−0.5 × (m−min) / (max−min)
Thus, the display number in step S24 is m × α. As a result, it is registered in step S26 as display number data.
      When m ← m <min
      When m × α ← min ≦ m <max
      When m × 0.5 ← max ≦ m
It becomes.
[0026]
  6 is a diagram illustrating an example of a display mode selection screen, FIG. 7 is a diagram illustrating an example of a 3D building display image according to each setting, and FIG. 8 is a diagram illustrating an example of a 3D building display screen according to each setting. In the map display device according to the present invention, for example, the “3D building display” option of the present invention is selected in the display mode selection screen for selecting the nearest display genre, two-screen display, locus display, etc. as shown in FIG. When a 3D building display is selected, a building is displayed with an image as shown in FIGS. 7 and 8, for example. In the automatic designation shown in FIG. 7 and FIG. 8, the display building setting process shown in FIG. 4 described above is performed, and the buildings having the number of floors greater than the designated number of floors in the third floor, the fifth floor, and the tenth floor are displayed. it's shown. In the screen of FIG. 6, 10m, 25m, 50m, and 100m indicate map scales of 1/1000, 1/2500, 1/5000, and 1/10000, and Auto indicates no floor designation. The system automatically selects buildings above the Nth floor. In addition, a right and left selection key is provided on the right side of the 3D building display item, and this selection key is used to select any of None, Auto, Second Floor, Third Floor,.
[0027]
Next, map display performed by converting the two-dimensional coordinates of the map data into a perspective map having a depth on the two-dimensional coordinate system will be described. FIG. 9 is a diagram for explaining a trapezoidal coordinate transformation algorithm, and FIG. 10 is a diagram for explaining a coordinate transformation algorithm for building height data. The conversion parameter 13 of the central processing unit 4 holds coordinate conversion parameters such as a trapezoid conversion parameter for converting the rectangular coordinates of the map into trapezoid coordinates and a curved surface conversion parameter for converting the coordinates of the curved surface into the coordinates of the projection plane. . The coordinate conversion unit 12 performs coordinate conversion on the map data composed of two-dimensional coordinates based on the coordinate conversion parameter held in the conversion parameter 13, and draws the coordinate-converted map data to output data from the output device 6. A perspective map is displayed on the screen.
[0028]
  First, a trapezoid conversion parameter in a case where coordinate conversion to a trapezoid as shown in FIG. 9B is performed on a two-dimensional coordinate space of map data as shown in FIG. 9A will be described. First, for the rectangle in the two-dimensional coordinate space of the map data, the width (1/2 of the length in the X direction) g is set as shown in FIG. 9A, and for the trapezoid, FIG. The length of the upper side (1/2 of the length in the X direction) a and the length of the lower side (1/2 of the length in the X direction) b are set as shown in FIG. A common vertical length (Y-direction length) L is set.
[0029]
If the new coordinate converted by the coordinate conversion unit 12 from P (X, Y) of the map data based on these parameters is P1 (sx, sy), first, the Y coordinate value sy is the upper side of the trapezoid. The length of the lower side of the trapezoid with respect to the product {aL + (b−a) Y} of the product of the length a and the vertical length L and the difference between the lengths of the upper and lower sides of the trapezoid (b−a) and the Y coordinate value The ratio of the product b · L · Y of the length b, the vertical length L and the Y coordinate value, that is,
[Equation 1]

Where k₁= B · L k₂= A ・ L k_Three= (Ba)
It is calculated by. Further, the X coordinate value sx is a value obtained by multiplying the difference (ba) between the length b of the lower side of the trapezoid and the length of the upper and lower sides of the trapezoid by the Y coordinate value and dividing it by the vertical length L of the trapezoid (b -A) Subtract sy / L and multiply by the ratio of the X coordinate value to the length g of the rectangle in the X direction, i.e.
[Equation 2]

Where k_Four= G k_Five= B k₆= (Ba) / L
It is calculated by.
[0030]
  Hereinafter, the conversion of the Y coordinate will be described first. In FIG. 9A, the equation of the oblique line is
    [Equation 3]
      Y = L · X / 2g + L / 2
It is represented by Therefore, the converted map is assumed so that the oblique straight line is maintained as a straight line after the conversion and the X coordinate is equally divided, and the X in the two-dimensional coordinates of this straight line and another map data is assumed. Consider a mesh triangle shown in FIG. 9B by a straight line with a constant coordinate value. Since these are similar, consider the ratio of the lengths of the sides of each triangle. First, the ratio of the vertical lengths of the triangles is (L-sy): sy. On the other hand, the length of the base of the triangle is a−Xa / g on the upper side and b + Xb / g on the lower side. Therefore, since the ratio of side lengths of similar triangles is equal,
    [Equation 4]
      (L-sy): sy = (a-Xa / g): (b + Xb / g)
It becomes. If X is deleted from this [Equation 4] and the above [Equation 3], [Equation 1] is obtained. Further, if the X coordinate value of the fixed value g converted to the upper side a and the lower side b is associated with the vertical length sy, (b−a) sy / L is obtained. [Equation 2] is obtained by multiplying the ratio with X.
[0031]
Next, a case where a three-dimensional building such as a building is displayed in a three-dimensional manner by two-dimensional coordinate conversion using trapezoid conversion parameters will be described. For example, when a building has data of a floor number n, the average floor height h is multiplied by the floor number n to obtain the height as n × h = H, and the height as a whole is not a floor n but a tower. When there is data of height H, coordinate conversion is performed based on the height H. The coordinate conversion of the height H to the Y coordinate value sy ′ in the Y coordinate value sy is performed by using, for example, [Equation 5] on the X coordinate value sx and the Y coordinate value sy converted on the two-dimensional plane. This can be done by obtaining the added value ΔY of the values.
[0032]
    [Equation 5]
      sy ′ = sy + ΔY
                  b-a sy
      Y = (1 -----------) H = (1-k₇sy) H
                    b L
        Where k₇= (B−a) / b · L = k_Three/ K₁
Therefore, as shown in FIG. 10A, the vertex coordinate value of the building with the height H at the point of (sx1, sy1) is
    [Equation 6]
      (Sx1, sy1 + ΔY) = {sx1, sy1 + (1-k₇sy) H}
The coordinates thus converted are connected with lines, the inside of the frame is filled with a predetermined color, and this processing is performed in order from the back to overwrite the display, as shown in FIG. It can be performed.
[0033]
As described above, the trapezoid conversion parameters are a, b, g, L, or k₁~ K₇And coordinate conversion of the three-dimensional building from these, coordinate values (X, Y), and height h can be executed by simple addition / subtraction / division / division calculation. Therefore, not only buildings but also three-dimensional buildings such as houses and bridges can be drawn three-dimensionally in the same manner. For example, as described later with reference to FIG. 12, a coordinate sequence representing the shape of a building as building data (Polygon data) and building floor information (or building height), coordinate conversion is performed as described above from each point consisting of two-dimensional coordinates and building floor information, and predetermined from the current position. The drawing response can be further improved by drawing only the buildings within the distance, and as the current position moves, only the buildings within a predetermined distance from the current position can be easily displayed in 3D. be able to.
[0034]
Specifically, the distance between the current position detected by the current position detection device and each building is calculated, and it is determined whether or not the distance is within a predetermined distance. If the determination result is within a predetermined distance, the coordinate conversion is performed and a stereoscopic display is performed. Here, when calculating the distance, the distance between the current position and the center point of the building may be used, or the distance between the current position and one coordinate in the coordinate string representing the shape of the building may be used. In order to guide the user to the destination with reference to the shape of the building, the user can build the building only along the route to the destination, or within a predetermined distance from the current position and the route. In addition, the above display modes may be combined. Further, the height H of the building may be increased or decreased within a predetermined distance from the current position and according to the distance from the current position. That is, the height H of the building is used as it is near the current position, and the value of the height H is reduced as the distance from the current position is increased. In addition, when displaying buildings, only buildings that are higher than a predetermined height or buildings that are ahead of the current position of the vehicle are displayed in three dimensions, and the current building or vehicle that does not reach the predetermined height is displayed. Buildings located behind the direction of travel in the direction of travel are displayed at the same height from the lowest in order to display in 3D or 3D instead of 3D or in 3D intersections. It goes without saying that the order and selection of buildings to be drawn can be freely combined, such as drawing.
[0035]
In the above [Expression 2], P (X, sy) is obtained from P (X, Y) and then P1 (sx, sy) is obtained by using the sy. Sx may be obtained from the coordinate values of. For example, in [Equation 2], when sx 'is obtained by using Y for sy, P (X, Y) is converted to P1' (sx ', sy) shown in FIG. The result of coordinate conversion becomes bowl shape.
[0036]
  Next, a configuration example of data used in the vehicle navigation apparatus provided with the map display device of the present invention will be described. FIG. 11 is a diagram showing an example of the configuration of main data files stored in the information storage device, and FIG. 12 is a diagram showing an example of the structure of building data.
[0037]
As shown in FIG. 11A, the guide road data file includes a road number, a length, road attribute data, an address of shape data, a size, an address of guide data, and a size for each number of roads n. It consists of data, and is stored as data necessary to calculate a route and perform route guidance by the route search unit. The road number is set for each direction (outbound path, return path) for each road between the branch points. The road attribute data is road guidance auxiliary information data, and the shape data is east longitude for each of the number of nodes m when divided by a plurality of nodes (sections) of each road as shown in FIG. , Has coordinate data consisting of north latitude. As shown in FIG. 11C, the guide data includes intersection (or branch point) names, traffic signal data, landmark data, caution point data, road name data, road name voice data, destination data addresses, and sizes. Consists of data.
[0038]
  As the structure of the building data stored in the information storage device 3, for example, as shown in FIG. 12A, the data of each of N buildings is stored next to the number N of building data. The data of each building includes information on the name, address (address), type, shape, height, and details of the building. The name is the name of the building if it is a building, the resident name if it is a private house, the name of the facility if it is a facility, the name of the facility such as “Chuo-dori” or “National Highway 1” if it is a road. It is a street name, and the address (address) is the address of the building. The shape of the building is the coordinate number n representing the shape and its coordinate value (x₀, Y₀), (X₁, Y₁) ......... (x_n-1, Y_n-1The type is information on general houses, condominiums, office buildings, public facilities, roads, parks, and the like. The height is information on the floor number and the height (m). When the height is stored in the number of floors, it is converted into height (m) information using a table. For example, in the case of a tenant building, the details are information about each resident, and for the number of names and each tenant, the name, telephone number, room number, classification (restaurant, convenience store, etc., business type, business description). Information. Therefore, as shown in FIG. 12B, coordinate values are sequentially read out as information related to the shape of the building, and connected and drawn with lines to display, for example, the planar shape of a building or a house or the topography of a park. it can.
[0039]
  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, in the above embodiment, the two-dimensional coordinates are converted to the two-dimensional coordinates of the perspective map by the trapezoidal transformation. However, the present invention may be similarly applied to other perspective maps that perform the conventional coordinate conversion. . In addition, when the floor is designated by the user, a building with a height higher than that floor is selected and displayed, and when there is no designation, a building with three or more floors is selected as a default, and the total number Gradually reduced the display rate from the minimum threshold to the maximum threshold from 100% to 50% of the upper limit, and when the maximum threshold was exceeded, the building was displayed with a uniform upper limit display rate of 50%. The display rate may be adjusted in the same manner even when the designation is made.
[0040]
  Furthermore, only one threshold is set for the number of displays, and the total number of building data in the drawing range is the total number up to the threshold. The number of displayed data may be reduced until the threshold value is exceeded, and if it exceeds the threshold value, it may be set to a fixed number of displayed values. In either case, the upper limit value of the displayed number is set. May be. In addition, the limitation on the number of displays is not uniform for the entire screen. The display area is divided into a plurality of areas such as two or three in the vertical direction, and the specified floor number, minimum threshold, maximum threshold, and display are divided for each area. You may set the upper limit of a rate and the upper limit of the number of displays. By doing in this way, for example, the number of floors of a building to be selected increases as the distance increases, and the building to be displayed for each region can be selected according to the distance, such as by reducing the number of displays. Further, the height of the building may be selected not by the number of floors but by the height itself (m), or by the floor area or volume.
[0041]
  In the above embodiment, the number of floors is stored as height data, and a building having a number of floors or more input by the user is selected. However, the height of the building is selected not by the number of floors but by the height itself (m). You may comprise as follows. In such a case, the height of the building is obtained by multiplying the data (number of floors) by a predetermined floor height of the first floor, and the selected building height is compared with the height entered by the user. You may make it do. Needless to say, the height (m) may be stored as the height data of the building.
[0042]
  Further, in the above embodiment, a building having a height higher than that specified by the user is selected, or a building having a height higher than that set automatically by the system is selected and displayed. The building is displayed lower as it goes above. Therefore, when comparing the buildings after coordinate conversion, as can be seen from FIG. 3 and FIG. 10, a relatively low building at the top of the screen is displayed, and a high building at the bottom of the screen may be deleted. As a result, the user feels uncomfortable with the map. Therefore, if you want to extract a building that is higher than the height entered by the user with respect to the height of the building after coordinate conversion, or if you want to automatically select a building, the building after coordinate conversion An average value may be obtained from the height of the object, and a building (of course, with respect to the height after coordinate conversion) having the average value or more may be selected and displayed. In addition, the reference | standard of the height displayed when selecting a building automatically may be predetermined height, for example, 5m.
[0043]
【The invention's effect】
  As is apparent from the above description, according to the present invention, in the map display device for displaying a building three-dimensionally, information storage means for storing building data having two-dimensional coordinates and height information, and the information Based on the two-dimensional coordinates and height information of the building data stored in the storage means, drawing control means for drawing the building three-dimensionally on the perspective map, and the building drawn by the drawing control means are displayed. And a display control means having a display number determining means for detecting the number of building data in the drawing range and determining the display number of the building, and determined from the higher one based on the height information. Since the number of displayed building data is selected and the building is drawn three-dimensionally on the perspective map, even if the building is displayed three-dimensionally, the map is not complicated, and the building that stands out for the user can be selected. Can be displayed .
[0044]
  Further, the display number determination means has a display number threshold, and the number of building data in the drawing range is the total number up to the threshold. When the number of building data reaches the threshold value, the ratio of the display number is reduced. When the number exceeds the threshold value, the display number is a fixed ratio, or the display value threshold value has the minimum threshold value and the maximum threshold value. The total number up to the minimum threshold is set, and when the ratio of the number of displays is reduced from the minimum threshold to the maximum threshold and the maximum threshold is exceeded, the display is set to a constant display ratio. When the position is displayed with a cursor or the like, a rough position of the current position can be easily obtained from the building on the map screen.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a map display device according to the present invention.
FIG. 2 is a diagram illustrating an example of a registration process of building data to be displayed.
FIG. 3 is a diagram illustrating an example of a building drawing process.
FIG. 4 is a diagram illustrating an example of a display building setting process in a building drawing process.
FIG. 5 is a diagram for explaining a setting example of parameters for controlling the number of displayed buildings.
FIG. 6 is a diagram showing an example of a display mode selection screen.
FIG. 7 is a diagram illustrating an example of a 3D building display image according to each setting.
FIG. 8 is a diagram illustrating an example of a 3D building display screen according to each setting.
FIG. 9 is a diagram for explaining a trapezoidal coordinate conversion algorithm.
FIG. 10 is a diagram for explaining a coordinate conversion algorithm for building height data;
FIG. 11 is a diagram showing a configuration example of main data files stored in the information storage device.
FIG. 12 is a diagram illustrating an example of the structure of building data.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Input device, 2 ... Current position detection device, 3 ... Information storage device, 4 ... Central processing unit, 5 ... Information transmission / reception device, 6 ... Output device, 11 ... Perspective display control part, 12 ... Coordinate conversion part, 13 ... Conversion parameter

Claims (6)

In a map display device that displays buildings three-dimensionally,
Information storage means for storing building data having two-dimensional coordinates and height information;
Drawing control means for drawing a building three-dimensionally on a perspective map based on the two-dimensional coordinates and height information of the building data stored in the information storage means;
Display means for displaying the building drawn by the drawing control means, and the drawing control means detects the number of the building data in the drawing range and determines the display number of the building. A map display device characterized by selecting the building data of the display number determined from the higher one based on the height information and rendering the building three-dimensionally on a perspective map.   The display number determining means has a display number threshold value, wherein the number of building data in the drawing range is the total number up to the threshold value, and when it exceeds the threshold value, the display number is a fixed ratio. Item 2. The map display device according to Item 1.   The display number determining means has a display number threshold, and reduces the ratio of the display number until the number of building data in the drawing range reaches the threshold, and sets the display number at a certain ratio when the threshold is exceeded. The map display device according to claim 1, wherein   The display number determination means has a minimum threshold value and a maximum threshold value as display value threshold values. The number of building data is the total number up to the minimum threshold value, and the ratio of the display number is reduced from the minimum threshold value to the maximum threshold value. The map display device according to claim 1, wherein when it exceeds, the display ratio is constant. A computer-readable recording medium for a map display device that three-dimensionally displays a building,
Building data having two-dimensional coordinates and height information;
A display number determining means for determining the number of buildings to be displayed by detecting the number of the building data in the drawing range based on the two-dimensional coordinates, from the higher one based on the height information of the building data; drawing control means for the building sterically drawn on perspective map based on the selected the two-dimensional coordinates and height information the building data number display the determined, and construction drawn by the drawing control means A computer-readable recording medium having recorded thereon a map display program for functioning as display means for stereoscopically displaying an object on a perspective map. A map display method for three-dimensionally displaying a building, wherein building data having two-dimensional coordinates and height information is stored in an information storage unit, and the building is stored in the information storage unit in a drawing range by a computer. The number of building data is detected based on the two-dimensional coordinates to determine the number of buildings to be displayed, and the building data of the determined number of displays is selected from the higher one based on the height information of the building data. A map display method characterized in that a building is three-dimensionally drawn on a perspective map based on the two-dimensional coordinates and height information, and the drawn building is three-dimensionally displayed on a perspective map.

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