JP2015125482A - Icon display program and icon display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively lessen processing load for displaying an icon image indicating the position of each movable body by efficiently grouping positional information on movable bodies.SOLUTION: An icon display program according to the present invention describes positions of each movable body using positional data configured to represent more detailed positions from upper bits toward lower bits, and groups positional data based on the number of digits of the upper bits common to the respective positional data.

Description

  The present invention relates to a technique for displaying an icon image indicating the position of a moving body on a screen.

  In recent years, position information composed of latitude and longitude of a moving object such as a person, a vehicle, a ship, and an aircraft can be obtained by a portable device equipped with a function of receiving a GPS (Global Positioning System) signal. For example, devices such as an automobile probe and a ship AIS (Automatic Identification System) are exemplified.

  The following Patent Document 1 uses geo-hash as a data format that describes position information of a moving object. In this document, since the geohash indicates a rectangular area rather than a specific point on the map, the accuracy is inferior compared to latitude and longitude, and a technique for solving this is disclosed.

JP 2013-045319 A

  When displaying the position information of a moving object on a screen such as a computer display, the position information may be visually displayed using an icon image representing the position of each moving object. In general, image display has a high processing load, and as the number of moving objects increases, the number of icon images on the screen increases accordingly, and icon display processing becomes a bottleneck for screen display. Further, when the scale range of the screen is expanded, the number of moving bodies included in the range increases, and accordingly, the number of icon images increases and the processing load increases.

  As a technique for reducing the processing load for displaying icon images, it is conceivable to group a plurality of pieces of position information located in the vicinity and assign a single icon image. This is expected to reduce the number of icons to be displayed and improve the drawing speed. However, since it is necessary to perform a new grouping process in addition to the conventional process, a sufficient improvement effect cannot be obtained depending on the processing speed.

  The present invention has been made in view of the problems as described above, and by effectively grouping the position information of the moving body, the processing load for displaying the icon image indicating the position of the moving body is effective. The purpose is to reduce it.

  The icon display program according to the present invention describes the position of a moving object using position data configured to represent a more detailed position from the upper bit to the lower bit, and is common among the position data. Group the position data based on the number of digits in the upper bits.

  According to the icon display program according to the present invention, it is possible to efficiently group the position information of the moving body and suppress the load for displaying the icon image indicating the position of the moving body.

It is a figure explaining the hash value showing the latitude. It is a figure explaining the hash value showing the latitude. It is a figure explaining the hash value showing the latitude. It is a figure which shows the process in which a latitude hash value and a longitude hash value are comprised collectively. It is a figure which shows the process in which a latitude hash value and a longitude hash value are comprised collectively. It is a figure which shows the process in which a latitude hash value and a longitude hash value are comprised collectively. It is a figure which shows the process in which the latitude longitude coordinate is converted into a geo hash value. It is a table | surface which shows the correspondence between each digit of geo hash, and a coordinate value. 1 is a configuration diagram of an icon display device 10 according to Embodiment 1. FIG. It is a figure which shows the structure of a position database 121, and a data example. It is a figure which shows the structure and data example of the icon database. It is a figure which shows the result of having converted the latitude longitude coordinate of four corners into geohash in a comparatively narrow map area. It is a figure which shows the structure and data example of a group table. 7 is a diagram illustrating a drawing result by the drawing unit 15; FIG. It is a figure which shows the result of having converted the latitude longitude coordinate of four corners into geohash in the map area | region wider than FIG. It is a figure which shows another example of data of the group table. 7 is a diagram illustrating a drawing result by the drawing unit 15; FIG. 5 is a flowchart for explaining the operation of a grouping unit 13.

<Description of Geohash>
In the embodiment of the present invention described below, the geo-hash used in Patent Document 1 is used as a format of position data describing the position of a moving object. In the following, the features of geohash will be described first, and then embodiments of the present invention will be described.

  A rectangular area may be used to represent the coordinates on the map. Conventionally, in order to express a rectangular area on a map, for example, a combination of numerical values of 3 to 4 such as latitude and longitude of two diagonal points of the rectangular area, center point coordinates and vertical and horizontal distances, center point and one end point, etc. In general, the rectangular area is represented by

  Geohash is a data format indicating a rectangular area on a map, and is expressed by alphanumeric characters of several characters. As the number of characters increases, a narrower rectangular area is expressed, and the accuracy of the expressed coordinates increases. That is, the higher order bits of the geohash represent a wider area including the coordinates indicated by the geohash value.

  When using the conventional coordinate format, in the process of grouping a plurality of coordinate values, the inter-coordinate distance in the screen coordinate system is calculated, and if the distance is equal to or less than a predetermined threshold, it is determined that they belong to the same group. Since this process needs to calculate all the distances between two points included in the scale range to be displayed, the burden of the grouping process is large.

  When geohash is used as position data, in the process of grouping a plurality of coordinate values, whether or not they belong to the same group (that is, the coordinate values are close to each other) Whether or not there is). Since this method does not need to calculate the distance between two points, it is considered that the grouping process can be performed at high speed. Furthermore, since the geohash value itself can be calculated in advance, the processing load for obtaining the geohash value does not matter.

  The present invention uses the above-mentioned features of geo-hash to efficiently group mobile object position data. As with geo-hash, if the position data is configured to describe a more detailed position from the high-order bit to the low-order bit (or the opposite direction), the coordinate value depends on whether the high-order bit is common. It can be determined whether or not they are close to each other. Therefore, if it is such a position data format, it can be used in place of the geohash. In the following, for convenience of explanation, it is assumed that geohash is used.

  In the embodiment described below, since geohash is used, it is assumed that position data in a two-dimensional coordinate system is handled. However, as with the geohash, if the position data is configured to describe a more detailed position from the upper bit to the lower bit (or the opposite direction), for example, data representing one-dimensional coordinates (that is, distance) Data representing three-dimensional coordinates can also be handled.

  1A to 1C are diagrams for describing a hash value representing latitude. FIG. 1A shows the relationship between the initial hash value and latitude. The hash value “0” indicates the range of latitude −90 ° to 0 °, and “1” indicates the latitude 0 ° to 90 °. Accordingly, the latitude hash value at position 10 is “1”. FIG. 1B shows the relationship between the second hash value and latitude. Hash value “0” indicates latitude 0 ° to 45 °, and “1” indicates latitude 45 ° to 90 °. Therefore, the latitude hash value at position 10 is “10”. FIG. 1C shows the relationship between the third hash value and latitude. The hash value “0” indicates latitude 0 ° to 22.5 °, and “1” indicates latitude 22.5 ° to 45 °. Therefore, the latitude hash value at position 10 is “100”.

  2A to 2C are diagrams illustrating a process of configuring a latitude hash value and a longitude hash value together. FIG. 2A shows a state in which the coordinate space is divided into two in the longitude direction, and the longitude hash values “0” and “1” are assigned, respectively. FIG. 2B shows a state in which the area of the longitude hash value “1” is divided into two in the latitude direction, and the latitude hash values “0” and “1” are assigned, respectively. Since the latitude hash value is added following the initial longitude hash value, the hash values of the respective areas are “11” and “10”. FIG. 2C shows a state in which the area of the hash value “11” is divided into two in the longitude direction, and the longitude hash values “0” and “1” are assigned, respectively. In the same manner, the longitude hash value and the latitude hash value are alternately assigned, and the hash value is configured so as to represent a more detailed position as the lower bits are obtained.

  FIG. 3 is a diagram illustrating a process of converting latitude and longitude coordinates into a geohash value. pdecimal is a decimal latitude / longitude coordinate value of latitude 35.610056 and longitude 139.7468694. The pdecimal is converted into a geo-hash value phash as described with reference to FIG. The hash 'is a bit string in which odd digits of the hash are alternately rearranged with the longitude hash value and the even digit as the latitude hash value. A character string p (GeoHash) obtained by dividing “phase” by 5 digits and converting it into base-32 which is a 32-digit number is a geo-hash. By following the process shown in FIG. 3 in reverse, the geohash can be converted back to decimal latitude and longitude coordinates.

  FIG. 4 is a table showing a correspondence relationship between each digit of the geo-hash and the coordinate value. Here, a geohash representing latitude and longitude coordinates (35.610056, 139.7748694) is illustrated. As shown in FIG. 4, in the geohash, each digit represents a rectangular area, and the lower the bit, the smaller the rectangular size. Therefore, comparing two geohashes in order from the most significant bit, the more common digits, the more the two geohashes represent coordinates closer to each other.

<Embodiment 1>
FIG. 5 is a configuration diagram of the icon display device 10 according to the first embodiment. The icon display device 10 is a device that displays an icon image indicating the position of a moving object on the screen, and includes a position data input unit 11, a database unit 12, a grouping unit 13, a display condition input unit 14, a drawing unit 15, and an output unit 16. Is provided.

  The position data input unit 11 includes a position data receiving unit 111 and a geohash providing unit 112. The position data receiving unit 111 receives position data describing the position of a moving body (for example, a person, a ship, an aircraft, or a vehicle) measured by GPS or the like. This position data describes coordinates at the time of transmission of the mobile object. The geohash providing unit 112 converts the received position data into a geohash and stores it in the position database 121. The processing of the position data input unit 11 can be performed independently from the processing of the grouping unit 13 and the drawing unit 15. The position data input unit 11 can also receive position data that has been previously converted to geohash. In this case, the geohash providing unit 112 is not necessary.

  The database unit 12 includes a position database 121, an icon database 122, and a map database 123. The location database 121 stores a geo-hash of the moving object. The icon database 122 stores an icon image used when the drawing unit 15 displays an icon image indicating the position of the moving object. The map database 123 stores a background map drawn by the drawing unit 15.

  The grouping unit 13 includes a geo-hash processing unit 131 and a group calculation unit 132. The geo-hash processing unit 131 converts the geo-hash into latitude and longitude coordinates, or performs the inverse conversion. The group calculation unit 132 groups the geohash stored in the position database 121 and stores it in a group table held by the position database 121. Details of the grouping process and the group table will be described later.

  The display condition input unit 14 is an interface for the user to specify a display map range and screen coordinates displayed by the drawing unit 15.

  The drawing unit 15 includes a map drawing unit 151 and an icon drawing unit 152. The map drawing unit 151 obtains and draws a map corresponding to the map range designated via the display condition input unit 14 from the map database 123. The icon drawing unit 152 refers to the group table stored in the position database 121 (which stores the grouping result by the grouping unit 13), and uses the icon image stored in the icon database 122 for each group. Assign and draw. The output unit 16 displays the drawing result by the drawing unit 15 on the screen.

  The position data input unit 11, the grouping unit 13, and the drawing unit 15 can be configured using hardware such as a circuit device that realizes these functions, and software that implements these functions is a CPU (Central Processing). It can also be configured by being executed by an arithmetic unit such as (Unit). The database unit 12 can be configured using a storage device such as a hard disk device. The display condition input unit 14 can be configured by an appropriate operation interface. The output unit 16 can be configured using a screen display device such as a display device.

  FIG. 6 is a diagram illustrating a configuration of the position database 121 and data examples. Here, a table for storing position data not grouped is shown. This table has a mobile object ID 1211, a declaration date and time 1212, a latitude 1213 and a longitude 1214, a direction 1215, a geo-hash 1216, an icon ID 1217, and a name 1218. The primary key is the mobile body ID 1211 and the declaration date 1212.

  The mobile object ID 1211 is an ID that uniquely identifies the mobile object. The reporting date and time 1212 is the date and time when the moving body transmits the position data. Latitude 1213 and longitude 1214 are coordinate values described by position data. A direction 1215 indicates a traveling direction clockwise with north as zero. The geohash 1216 is obtained by converting latitude 1213 and longitude 1214 into geohash. The icon ID 1217 is an ID for specifying an icon image to be assigned when the mobile object is displayed on the screen. The name 1218 is the name of the mobile object.

  FIG. 7 is a diagram illustrating the configuration of the icon database 122 and data examples. The icon database 122 includes an icon ID 1221, a width 1222, a height 1223, a width offset 1224, a height offset 1225, a group icon ID 1226, and icon data 1227. The primary key is the icon ID 1221.

  The icon ID 1221 is an ID for uniquely identifying each icon image data. Each of the width 1222 and the height 1223 is a pixel size of the icon image. The width offset 1224 and the height offset 1225 are the center point coordinates of the icon image with the origin at the upper left corner of the icon image, and correspond to the coordinate values of the position data corresponding to the icon image. The group icon ID 1226 specifies an icon ID 1221 of an icon image used when grouping the icon images. Since the group icon image is not further grouped, this field of the group icon image is NULL. Icon data 1227 is icon image data.

  FIG. 8 is a diagram illustrating a result of converting the latitude and longitude coordinates of the four corners into a geohash in a relatively narrow map region. In the example shown in FIG. 8, the common part between the geo-hashes of the four corner coordinates is “111011010000111001101110010001000”, and the common digit number is 31.

  FIG. 9 is a diagram illustrating a configuration of the group table 90 and data examples. The group table 90 is a table for storing a result of grouping position data stored in the position database 121 by the grouping unit 13. Here, an example of data obtained as a result of grouping the position data of FIG. 6 in the relatively narrow map area shown in FIG. 8 is shown.

  The group table 90 has a group ID 91, a latitude 92 and a longitude 93, a direction 94, an icon ID 95, a name 96, and a moving body ID 97.

  The group ID 91 is obtained by cutting out a common upper digit of a plurality of geo-hashes and expressing it with Base-32. Latitude 92, longitude 93, and direction 94 retain the original latitude, longitude, and direction as they are for position data that are not grouped, and for the position data that are grouped, the latitude and longitude obtained by reversely converting the group ID 91 as a geohash. Hold and the direction 94 is zero. The icon ID 95 holds a corresponding icon ID 1221 for position data that is not grouped, and holds a corresponding group icon ID 1226 for position data that is grouped. The name 96 substitutes a corresponding name 1218 for position data that is not grouped, and holds NULL for position data that is grouped. The moving body ID 97 holds the corresponding moving body ID 1211 for position data that is not grouped, and holds NULL for position data that is grouped.

  FIG. 10 is a diagram illustrating a drawing result by the drawing unit 15. Here, an example is shown in which the group table of FIG. 9 is displayed on the screen in a relatively narrow map region shown in FIG. The map area can be expressed in either a screen coordinate system or a map coordinate system. In the example shown in FIG. 10, the coordinates of the four corners with the screen width of the screen coordinate system set to 600 pixels, the screen height set to 480 pixels, and the origin at the upper left are defined. Similarly, the coordinates of each corner of the map coordinate system with the screen width and screen height of 0.003125 ° and the origin at the upper left are defined. The icon images 1001 to 1003 correspond to the records on the first to third lines in FIG.

  FIG. 11 is a diagram showing the result of converting the latitude and longitude coordinates of the four corners into a geohash in a map area wider than FIG. In the example shown in FIG. 8, the common part between the geo-hashes of the four corner coordinates is “11101101000011100110”, and the common digit number is 20.

  FIG. 12 is a diagram illustrating another example of data in the group table 90. Here, an example of data obtained as a result of grouping the position data of FIG. 6 in the relatively wide map area shown in FIG. 11 is shown. When the map area is widened, the number of moving objects that are close to each other on the screen increases, so that icon images are easily grouped. In the data example shown in FIG. 12, unlike the data example of FIG. 9, the records in the first row are grouped, so that the direction 94, name 96, and mobile ID 97 are 0 °, NULL respectively according to the above rules. , It is NULL. The icon ID 95 is “2” (record on the second line in FIG. 7) indicating the group icon image.

  FIG. 13 is a diagram illustrating a drawing result by the drawing unit 15. Here, an example is shown in which the group table of FIG. 12 is displayed on the screen in a relatively narrow map area shown in FIG. The screen width and screen height are 0.1 °. Icon images 1301 to 1302 correspond to the records in the first and second lines in FIG.

<Description of processing outline>
FIG. 14 is a flowchart for explaining the operation of the grouping unit 13. Hereinafter, each step of FIG. 14 will be described.

(FIG. 14: Step S1401)
The grouping unit 13 initializes the following four variables. (A) c_hash: a variable for storing a hash value common in the map range drawn by the drawing unit 15; (b) c_digit: a number of binary representation digits of the hash value common in the map range drawn by the drawing unit 15 A variable to be stored; (c) g_digit: a variable to store a threshold value of the number of common digits used when determining whether position data belongs to the same group; (d) g_table: a group table 90.

(FIG. 14: Step S1402)
The geo-hash processing unit 131 converts the position data of the four corners of the map range drawn by the drawing unit 15 into a geo-hash. The geo-hash processing unit 131 converts each geo-hash into a binary number, and stores a common part counted from the most significant bit in c_hash. The geo-hash processing unit 131 stores the number of digits of the upper digit common part of the geo-hash stored in c_hash in c_digit.

(FIG. 14: Step S1402: Supplement)
In the data examples described with reference to FIGS. 8 to 10, c_hash is “11101101000011100110111000000001000”, and c_digit is 31. In the data example described with reference to FIGS. 11 to 13, c_hash is “11101101000011100110” and c_digit is 20.

(FIG. 14: Steps S1403 to S1406)
The group calculation unit 132 obtains the screen width / icon width for drawing the map by the drawing unit 15 and stores it in the variable ratio_x, and obtains the screen height / icon height and stores it in the variable ratio_y (S1403). The group calculation unit 132 compares ratio_x and ratio_y (S1404). When the ratio_x is smaller, the binary digit number is stored in g_digit (S1405), and when the ratio_y is smaller, the binary digit number is stored in g_digit (S1406). Here, it is assumed that g_digit = 4, for example.

(FIG. 14: Steps S1403 to S1406: Supplement 1)
These steps are for determining the maximum number of icon images that can be arranged when icon images are arranged on the map without any gaps. That is, it is considered most effective to perform grouping with a granularity of the group icon images that do not overlap each other as a result of grouping the position data (or the overlapping portion is very small). The group granularity is obtained and stored in g_digit, which is used in the subsequent steps.

(FIG. 14: Steps S1403 to S1406: Supplement 2)
For example, assume that ratio_x = ratio_y = 6. In this case, it is considered to be most efficient to perform grouping so that the map is divided into six rectangular areas in the vertical and horizontal directions. Although 3 bits are required to express 6 groups, when grouping is performed using the upper 3 bits of the geohash as will be described later, a maximum of 8 groups are generated, and the group icon images overlap each other. there is a possibility. Therefore, in these steps, a value obtained by subtracting 1 from the binary digits of ratio_x and ratio_y is adopted as g_digit.

(FIG. 14: Step S1407)
The group calculation unit 132 performs the following steps for each record (assuming a total of N records) having the latest declaration date and time 1212 among the records stored in the position database 121.

(FIG. 14: Steps S1408 to S1409)
The group calculation unit 132 stores the record acquired from the position database 121 in the variable row (S1408). The group calculation unit 132 determines whether the coordinates (latitude 1213 and longitude 1214) held by the row are within the map range (S1409). If it is outside the range, the process returns to step S1407 to process the next record, and if it is within the range, the process proceeds to step S1410. For example, the mobile object ID 1211 = “2345671” in FIG. 6 is out of the scope of this step because it is out of the map range.

(FIG. 14: Steps S1410 to S1412)
The group calculation unit 132 converts the geohash 1216 held in the row into a binary number representation, and generates a group ID by extracting the upper (c_digit + 2 * g_digit) digits (S1410). The group calculation unit 132 determines whether the generated group ID exists in g_table (S1411). If it does not exist, a new record is inserted into g_table (S1412). If it exists, the process proceeds to step S1413.

(FIG. 14: Step S1410: Supplement)
Since c_digit is a high-order bit common in the map range drawn by the drawing unit 15, the high-order c_digit bit of the position data existing in the same range is always common. Further, since the geohash alternately arranges longitude bits and latitude bits, the value of g_digit needs to be doubled. Therefore, in this step, c_digit + 2 * g_digit is determined as the group ID.

(FIG. 14: Step S1412: Supplement)
This step corresponds to generating a new group constituted by a single position data. Therefore, the group calculation unit 132 stores the latitude 1213, longitude 1214, direction 1215, icon ID 1217, name 1218, and moving body ID 1211 held in the row as they are in g_table.

(FIG. 14: Step S1413)
The group calculation unit 132 confirms whether or not the icon ID 95 corresponding to the generated group ID is a group icon. Specifically, the icon database 122 is referenced using the icon ID 95 as a key, and if the group icon ID 1226 is NULL, the icon ID 95 is a group icon image. If it is not a group icon, the process proceeds to step S1414. If it is a group icon, the process returns to step S1407 to process the next record.

(FIG. 14: Step S1413: Supplement)
If the same group ID already exists in g_table and the icon ID 95 of the group ID is a group icon (No in this step), the group ID has already been grouped. Not necessary. Therefore, in this case, the process returns to step S1407. When the same group ID already exists in g_table and the icon ID 95 of the group ID is not a group icon (in the case of Yes in this step), the group ID is not grouped by a single mobile object. Since it is configured, the group ID generated in step S1410 needs to belong to the group. Therefore, in this case, the process proceeds to step S1414 to execute the process.

(FIG. 14: Step S1414)
The group calculation unit 132 stores the values obtained by inversely converting the latitude and longitude into the latitude and longitude 93 using the group ID as a geohash, the direction 94 is set to 0, and the name 96 and the moving body ID 97 are set to NULL. The group calculation unit 132 refers to the icon database 122 using the icon ID 95 of the previously existing record as a key, and stores the value of the corresponding group icon ID 1226 in the icon ID 95. That is, a record composed of only a single position data before the execution of this step is replaced with a group composed of a plurality of position data by this step.

<Embodiment 1: Summary>
As described above, the icon display device 10 according to the first embodiment groups position data based on whether the upper bits of the geohash are common, and assigns the same icon image to the same group. Thereby, it is possible to efficiently narrow down the icon images of the moving objects to be displayed on the map, and improve the drawing processing speed while suppressing the processing burden of grouping the position data.

  Further, the icon display device 10 according to the first embodiment automatically determines the group granularity g_digit based on the ratio_x or the ratio_y. Thus, the optimum number of groups can be automatically determined without the user specifying parameters such as the total number of groups.

  On the other hand, in the first embodiment, for example, the user may want to specify the total number of groups on the map in advance via the display condition input unit 14. In this case, the total number of groups is counted immediately before the end of the flowchart of FIG. 14, and when this number falls below the target number, g_digit is increased and FIG. 14 is re-executed. 14 may be performed again. However, many repetition processes occur, which is not desirable from the viewpoint of speeding up.

<Embodiment 2>
When the position data input unit 11, the grouping unit 13, and the drawing unit 15 are configured by software, these software can be implemented in the form of a stand-alone application that operates on a computer, or an add-on that operates on a Web browser. It can also be implemented in the form of a program or script program.

  When each of the functional units is implemented as a program that operates on a Web browser, the position data receiving unit 111 can receive a geohash by an HTTP request. Similarly, the icon database 122 and the map database 123 can be acquired via a network by an HTTP request. The location database 121 can be stored in a local memory or the like of a computer that executes a Web browser.

  DESCRIPTION OF SYMBOLS 10: Icon display apparatus, 11: Position data input part, 111: Position data receiving part, 112: Geo hash provision part, 12: Database part, 121: Position database, 122: Icon database, 123: Map database, 13: Group Conversion unit, 131: geo-hash processing unit, 132: group calculation unit, 14: display condition input unit, 15: drawing unit, 151: map drawing unit, 152: icon drawing unit, 16: output unit.

Claims (7)

A program for causing a computer to execute a process of displaying an icon image indicating the position of a moving body on a screen,
A reception step of receiving position data describing positions of a plurality of the mobile objects, wherein the position data is configured to describe more detailed positions of the mobile objects from an upper bit toward a lower bit; Receiving step,
A grouping step for positionally grouping the moving bodies corresponding to the position data with reference to the number of common bit digits that are common from the most significant bit among the position data;
A single icon image is assigned to each moving body determined to belong to the same group in the grouping step, and each icon image corresponding to the position of each moving body is displayed on the screen. Display step,
An icon display program characterized in that the program is executed. In the grouping step, the computer is
When the number of common bit digits between a plurality of the position data is greater than or equal to a determination threshold value, the mobile units corresponding to the position data are determined to belong to the same group,
In the grouping step, the computer further includes:
The icon display program according to claim 1, wherein the determination threshold value is calculated so that the icon images can be arranged on the screen without overlapping each other. In the grouping step, the computer is
Obtaining a screen size of the screen;
Obtaining a pixel size of the icon image on the screen;
Determining a maximum number of the icon images that can be arranged on the screen without overlapping each other by determining a ratio of the pixel size to the screen size;
Determining the determination threshold so that each mobile unit is grouped into a group equal to or less than the maximum number;
The icon display program according to claim 2, wherein: The position data is
Configured to describe the position of the mobile body in a two-dimensional coordinate system;
In the grouping step, the computer is
The number of the icon images that can be arranged on the screen without overlapping each other in the width direction of the screen, and the number of the icon images that can be arranged on the screen without overlapping each other in the height direction of the screen. The icon display program according to claim 3, wherein the smaller one of the number is adopted as the maximum number. The icon display program is stored in the computer.
Obtaining a target number of the total number of groups obtained by the grouping;
When the number of groups obtained by the grouping step is larger than the target number, the grouping total number is calculated by repeating the grouping step and the display step after reducing the determination threshold. Approaching the target number;
When the number of groups obtained by the grouping step is less than the target number, the grouping step is repeated by repeating the grouping step and the display step after increasing the determination threshold value, thereby obtaining the total number of groups. Approaching the target number;
The icon display program according to any one of claims 1 to 4, wherein the icon display program is executed. The icon display program according to any one of claims 1 to 5, wherein the position data is described as geo-hash data. An apparatus for displaying an icon image indicating the position of a moving object on a screen,
A receiving unit that receives position data describing the positions of a plurality of the mobile objects, wherein the position data is configured to describe more detailed positions of the mobile objects from an upper bit toward a lower bit. The receiving part,
A grouping unit that positionally groups the mobiles corresponding to the position data based on the number of common bit digits counted from the most significant bit among the position data;
A single icon image is assigned to each of the moving objects determined by the grouping unit to belong to the same group, and each icon image corresponding to the position of each moving object is displayed on the screen. Display,
An icon display device comprising:

Images