CN104102771B - Automatic drawing method for land-sea ecotone meteorological isolines - Google Patents

Automatic drawing method for land-sea ecotone meteorological isolines Download PDF

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CN104102771B
CN104102771B CN201410318436.5A CN201410318436A CN104102771B CN 104102771 B CN104102771 B CN 104102771B CN 201410318436 A CN201410318436 A CN 201410318436A CN 104102771 B CN104102771 B CN 104102771B
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杜震洪
刘仁义
张丰
林贤辉
王叶晨梓
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Zhejiang University ZJU
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Abstract

本发明公开了一种海陆交错带气象等值线自动绘制方法。包括如下步骤:1)从多维海洋气象数据中读取数据,并获取海陆分界数据,进行叠加分析分离出海洋区域数据;2)设定判断噪点的阈值,并对每个像元进行判断,若像元为噪点,对该像元进行校正,得到海洋区域有效数值范围;3)根据海洋区域的有效数值范围得到全部区域的一个划分;4)分别构建海洋区域和其他区域的间隔表,设置各个区域不同疏密的间隔;5)合并海洋区域和其他区域的间隔;6)利用MATLAB批量读取数据,并将间隔应用于MATLAB等值线绘制指令,实现自动绘制。本发明绘制的等值线可有效突出海洋区域要素的变化,并兼顾陆地区域气象要素的表现,可应用于海陆交错带气象专题图的制作等领域。The invention discloses a method for automatically drawing meteorological contours in an interlaced zone of sea and land. It includes the following steps: 1) Read the data from the multi-dimensional marine meteorological data, obtain the sea-land boundary data, perform overlay analysis to separate the ocean area data; 2) set the threshold for judging the noise, and judge each pixel, if The pixel is a noise point, and the pixel is corrected to obtain the effective numerical range of the ocean area; 3) A division of the entire area is obtained according to the effective numerical range of the ocean area; 4) The interval tables for the ocean area and other areas are respectively constructed, and each 5) Merge the intervals of ocean areas and other areas; 6) Use MATLAB to read data in batches, and apply the intervals to MATLAB contour drawing commands to realize automatic drawing. The isolines drawn by the invention can effectively highlight the changes of the elements in the ocean area, and take into account the performance of the meteorological elements in the land area, and can be applied to the fields of making meteorological thematic maps of the sea-land transition zone and the like.

Description

一种海陆交错带气象等值线自动绘制方法A Method for Automatically Drawing Meteorological Contours in the Sea-land Ecotone

技术领域technical field

本发明涉及海洋气象等值线绘制的技术领域。尤其涉及一种海陆交错带气象等值线自动绘制方法。The invention relates to the technical field of marine meteorological contour drawing. In particular, it relates to a method for automatically drawing meteorological contours in the sea-land ecotone.

背景技术Background technique

等值线是制图对象中数值相等的各点连成的平滑曲线,它在水文、地质、海洋、大气等诸多领域都有非常重要的用途,比如气压场中的等压线图、大地测绘中的等高线图、地质中的矿体等值线图等等。目前等值线绘制和填充的方法已经比较成熟,但在海洋气象领域存在问题。海洋气象数据包含陆地和海洋区域,要素数值在海洋上变化平缓,而在陆地上变化显著。采用传统的等值线间隔设置方法会使等值线集中在陆地区域,在海洋区域则缺少可分辨的等值线,而其正是海洋气象工作者重点关注的区域。因此,如何自动地设置海洋气象等值线间隔,从而提高绘制要素的信息量,突出兴趣区域,是一个亟待解决的问题。Contour is a smooth curve formed by connecting points with equal values in the mapping object. It has very important uses in many fields such as hydrology, geology, ocean, atmosphere, etc., such as isobar maps in pressure fields and geodetic mapping. Contour maps of ore body contour maps in geology, etc. At present, the methods of contour drawing and filling are relatively mature, but there are problems in the field of marine meteorology. Oceanographic meteorological data includes land and ocean areas, and element values vary gradually over oceans but significantly over land. Using the traditional method of contour interval setting will make the contours concentrated in the land area, and there is a lack of distinguishable contours in the ocean area, which is the area that marine meteorologists focus on. Therefore, how to automatically set the interval of marine meteorological contours, so as to increase the information content of the drawn elements and highlight the regions of interest, is an urgent problem to be solved.

对于不等间距等值线,目前有两种间隔设置的方法:一是绘制人员根据具体数据手动设置;二是基于面积统计的间隔设置。手动设置法是利用软件绘制完等值线后,根据效果不断调整间隔,直到出来比较满意的结果。这种方法往往可以得到很好的效果,但是绘制过程麻烦,耗时耗力。面积统计的方法在一定程度上解决了人工绘制的问题,可以实现业务化批量处理,但是应用于海洋气象这类特殊数据时,绘制出的等值线效果无法满足专业要求。比如大气等压线的间隔通常需要设置为特定数值,如2.5百帕或者4百帕,而面积统计的方法只根据等面积原则划分,无法解决这类特殊需求。For contour lines with unequal intervals, there are currently two methods for setting intervals: one is manual setting by the drawer according to specific data; the other is interval setting based on area statistics. The manual setting method is to use the software to draw the contour line, and then adjust the interval according to the effect until a satisfactory result is obtained. This method can often get good results, but the drawing process is cumbersome, time-consuming and labor-intensive. The method of area statistics solves the problem of manual drawing to a certain extent, and can realize business batch processing, but when it is applied to special data such as marine meteorology, the drawn contour effect cannot meet professional requirements. For example, the interval of atmospheric isobars usually needs to be set to a specific value, such as 2.5 hPa or 4 hPa, and the method of area statistics is only divided according to the principle of equal area, which cannot solve such special needs.

针对以上问题,本发明提出一种海陆交错带气象等值线自动绘制方法,首先将原始要素与海陆分界数据做叠加分析,提取出海洋区域,然后进行斑点去噪计算得到海洋区域数值范围,再结合映射表选择合适的间隔值,合并海洋和陆地区域获得不等间距间隔,最后将间隔应用于MATLAB等值线绘制指令实现自动绘制。基于该方法可以实现海陆交错带气象等值线的自动绘制,并且能够突出海洋区域信息。In view of the above problems, the present invention proposes a method for automatically drawing meteorological contours in the sea-land transition zone. First, the original elements and the sea-land boundary data are superimposed and analyzed, and the ocean area is extracted, and then the numerical range of the ocean area is obtained by performing spot denoising calculations, and then Combined with the mapping table to select the appropriate interval value, merge the ocean and land areas to obtain unequal interval intervals, and finally apply the interval to the MATLAB contour drawing command to realize automatic drawing. Based on this method, the automatic drawing of meteorological contours in the sea-land ecotone can be realized, and the information of the ocean area can be highlighted.

发明内容Contents of the invention

本发明的目的是为克服现有技术存在的问题,提供一种海陆交错带气象等值线自动绘制方法。The purpose of the present invention is to provide a method for automatically drawing meteorological contours in the sea-land transition zone in order to overcome the problems in the prior art.

一种海陆交错带气象等值线自动绘制方法包括如下步骤:A method for automatically drawing meteorological contours in the sea-land ecotone includes the following steps:

1)从多层多变量的海洋气象原始数据文件中读取出待绘制等值线的一层数据,再获取与该数据格式一致的海陆分界数据,利用海陆分界数据对原始数据做叠加分析,分离出海洋区域数据;1) Read out the layer of data to be drawn from the multi-layer and multi-variable marine meteorological raw data files, and then obtain the sea-land boundary data consistent with the data format, and use the sea-land boundary data to perform overlay analysis on the original data, Separate out ocean area data;

2)设定判断噪点的阈值,遍历数据中的每个像元,若当前像元的数值与周围相连的八个像元的方差减去整体的方差大于给定的阈值,则认为该像元为噪点,对该像元进行校正,以此得到海洋区域有效数值范围;2) Set the threshold for judging the noise, traverse each pixel in the data, if the value of the current pixel and the variance of the eight surrounding pixels minus the overall variance is greater than the given threshold, then the pixel is considered is the noise point, and the pixel is corrected to obtain the effective numerical range of the ocean area;

3)根据海洋区域的有效数值范围得到全部区域的一个划分;3) Obtain a division of the entire area according to the effective numerical range of the ocean area;

4)分别构建海洋区域和其他区域的间隔表,根据间隔表设置各个区域不同疏密的间隔;4) Construct the interval table of the ocean area and other areas respectively, and set the intervals of different densities in each area according to the interval table;

5)合并海洋区域和其他区域的间隔;5) Merge intervals between oceanic areas and other areas;

6)利用MATLAB批量读取数据,并将步骤5)合并后的间隔应用于MATLAB等值线绘制指令,实现自动绘制。6) Use MATLAB to read data in batches, and apply the merged interval in step 5) to the MATLAB contour drawing command to realize automatic drawing.

所述的步骤1)包括:从一个多层多变量的海洋气象原始数据文件中读取出待绘制等值线的一层数据,该层数据是由n行m列的二维规则格网构成,再获取与该数据格式一致的n行m列的海陆分界数据,海陆分界数据包含与其相对应的二值数据,每个像元都引用相同的地理位置,海陆分界二值数据中0代表其他,1代表海洋,利用海陆分界数据对原始数据做叠加分析,分离出海洋区域数据。The step 1) includes: reading out a layer of data to be drawn isolines from a multi-layer and multi-variable marine meteorological raw data file, the layer data is composed of a two-dimensional regular grid of n rows and m columns , and then obtain the sea-land boundary data with n rows and m columns consistent with the data format. The sea-land boundary data contains the corresponding binary data, and each pixel refers to the same geographical location. 0 in the sea-land boundary binary data represents other , 1 represents the ocean, using the sea-land boundary data to do overlay analysis on the original data, and separate the ocean area data.

所述的步骤2)包括:设定一个判断噪点的阈值,遍历数据中的每个像元,若当前像元的数值f(i,j)与周围相连的八个像元的方差σ2减去整体的方差大于给定的阈值,则认为该像元为噪点,该方法可用以下公式表示:The step 2) includes: setting a threshold for judging the noise, traversing each pixel in the data, if the value f(i, j) of the current pixel is subtracted from the variance σ 2 of the surrounding eight connected pixels remove the overall variance If it is greater than a given threshold, the pixel is considered to be a noise point. This method can be expressed by the following formula:

式中:gl为f(i,j)点周围邻点的数值;In the formula: g l is the value of adjacent points around f(i, j) point;

当确认某像元为噪点时,用以下公式计算的结果替换原值,When it is confirmed that a pixel is a noise point, replace the original value with the result calculated by the following formula,

式中:f′(i,j)为像元的新亮度;P为该像元是噪点的概率,In the formula: f′(i, j) is the new brightness of the pixel; P is the probability that the pixel is a noise point,

经以上校正后的海洋区域数据可以得到海洋区域有效数值范围。The ocean area data after the above correction can obtain the effective numerical range of the ocean area.

所述的步骤3)包括:得到整体数值范围,再去除海洋区域的计算结果,以此得到其他区域的数值范围;海洋区域数值范围QO=[minO,maxO]可以将其他区域数值范围分为两个部分,上界QL1=(minL1,maxL1]和下界QL2=[minL2,maxL2),它们是全部区域的范围QA=[minA,maxA]的一个划分;The step 3) includes: obtaining the overall numerical range, and then removing the calculation result of the ocean area, so as to obtain the numerical range of other areas; the numerical range of the ocean area QO=[minO, maxO] can divide the numerical range of other areas into two parts, upper bound QL 1 =(minL 1 , maxL 1 ] and lower bound QL 2 =[minL 2 , maxL 2 ), they are a division of the range QA=[minA, maxA] of the whole area;

QA=QL1∪QO∪QL2 (3)QA=QL 1 ∪QO∪QL 2 (3)

式中QL1、QO与QL2两两交集都为空;In the formula, the intersection of QL 1 , QO and QL 2 is empty;

若其他数值全部大于海洋区域,则QL1为空集,若其他数值全部小于海洋区域,则QL2为空集。If all other values are greater than the ocean area, then QL 1 is an empty set, and if all other values are less than the ocean area, then QL 2 is an empty set.

所述的步骤4)包括:对于求出的海洋区域和其他区域的数值范围,构建间隔表设置各个区域不同疏密的间隔,间隔表区域字段分为兴趣区域和其他区域,不同区域的间隔设置原则不同,兴趣区域间隔较小,对应的等值线也较密,其他区域间隔相对较大,绘制的等值线也较稀疏;同一类区域因为数值范围的不同设置不同间隔,所述的数值范围关注的是范围差所属的区间,海洋区域的数值范围差为maxO-minO。Described step 4) comprises: for the numerical range of the marine area and other areas of seeking, build interval table and set the interval of different densities in each area, interval table area field is divided into interest area and other areas, the interval setting of different areas The principles are different, the interval of the interest area is small, and the corresponding contour lines are also relatively dense, while the intervals of other areas are relatively large, and the contour lines drawn are also relatively sparse; the same type of area has different intervals due to different value ranges, and the stated value The range focuses on the interval to which the range difference belongs, and the numerical range difference of the ocean area is maxO-minO.

所述的步骤5)包括:通过步骤4)构建的间隔表的映射,得到以下间隔设置,海洋区域数值范围间隔QIO=[minO,intervalO,maxO],其它区域数值范围上界QIL1=(minL1,intervalL1,maxL1]和下界QIL2=[minL2,intervalL2,maxL2),合并海洋区域和其他区域的间隔,得到整体区域的间隔QIA,Described step 5) comprises: by the mapping of the interval table that step 4) builds, obtains following interval setting, marine area numerical range interval QIO=[minO, intervalO, maxO], other area numerical range upper limit QIL1=(minL 1 , intervalL 1 , maxL 1 ] and the lower bound QIL2=[minL 2 , intervalL 2 , maxL 2 ), combine the intervals of the ocean area and other areas to obtain the interval QIA of the overall area,

QIA=QIL1∪QIO∪QIL2 (4)QIA QIL1∪QIO∪QIL2 (4)

式中QIL1、QIO和QIL2两两交集都为空。In the formula, the intersection of QIL 1 , QIO and QIL 2 is empty.

所述的步骤6)包括:利用MATLAB批量读取数据,调用MATLAB等值线绘制指令contour或contourf,将合并后的间隔QIA应用于该指令,实现自动批量绘制。The step 6) includes: using MATLAB to read data in batches, calling the MATLAB contour drawing command contour or contourf, and applying the combined interval QIA to the command to realize automatic batch drawing.

本发明与现有技术相比具有的有益效果是:本发明通过设置不等间距间隔,确保海洋区域有更密集的等值线,能重点展现出海洋区域的数值变化,使得在海洋区域中原本较为稀疏的等值线分布得更加科学、丰富;而在次重要的陆地区域,原本较为密集的等值线相对趋于稀疏,以降低该区域等值线的混乱程度;海洋区域和陆地区域等值线所体现的整体信息更加完整,能提供更有意义的参考价值。Compared with the prior art, the present invention has the beneficial effects that: the present invention ensures that the ocean area has denser contours by setting unequal intervals, and can focus on showing the numerical changes in the ocean area, so that in the ocean area, the original The sparser isolines are distributed more scientifically and abundantly; while in less important land areas, the originally denser isolines tend to be relatively sparse to reduce the confusion of the isolines in this area; ocean areas and land areas, etc. The overall information reflected by the value line is more complete and can provide more meaningful reference value.

附图说明:Description of drawings:

图1是海陆交错带气象等值线自动绘制方法;Figure 1 shows the automatic drawing method of meteorological contours in the sea-land ecotone;

图2是陆地表面气压数值分布;Figure 2 is the numerical distribution of air pressure on the land surface;

图3是海洋表面气压数值分布;Figure 3 is the numerical distribution of ocean surface air pressure;

图4是等值线绘制成果。Figure 4 is the contour drawing results.

具体实施方式:detailed description:

如图1所示,海陆交错带气象等值线自动绘制方法包括如下步骤:As shown in Figure 1, the method for automatically drawing meteorological contours in the sea-land ecotone includes the following steps:

1)从多层多变量的海洋气象原始数据文件中读取出待绘制等值线的一层数据,再获取与该数据格式一致的海陆分界数据,利用海陆分界数据对原始数据做叠加分析,分离出海洋区域数据;1) Read out the layer of data to be drawn from the multi-layer and multi-variable marine meteorological raw data files, and then obtain the sea-land boundary data consistent with the data format, and use the sea-land boundary data to perform overlay analysis on the original data, Separate out ocean area data;

2)设定判断噪点的阈值,遍历数据中的每个像元,若当前像元的数值与周围相连的八个像元的方差减去整体的方差大于给定的阈值,则认为该像元为噪点,对该像元进行校正,以此得到海洋区域有效数值范围;2) Set the threshold for judging the noise, traverse each pixel in the data, if the value of the current pixel and the variance of the eight surrounding pixels minus the overall variance is greater than the given threshold, then the pixel is considered is the noise point, and the pixel is corrected to obtain the effective numerical range of the ocean area;

3)根据海洋区域的有效数值范围得到全部区域的一个划分;3) Obtain a division of the entire area according to the effective numerical range of the ocean area;

4)分别构建海洋区域和其他区域的间隔表,根据间隔表设置各个区域不同疏密的间隔;4) Construct the interval table of the ocean area and other areas respectively, and set the intervals of different densities in each area according to the interval table;

5)合并海洋区域和其他区域的间隔;5) Merge intervals between oceanic areas and other areas;

6)利用MATLAB批量读取数据,并将步骤5)合并后的间隔应用于MATLAB等值线绘制指令,实现自动绘制。6) Use MATLAB to read data in batches, and apply the merged interval in step 5) to the MATLAB contour drawing command to realize automatic drawing.

所述的步骤1)包括:从一个多层多变量的海洋气象原始数据文件中读取出待绘制等值线的一层数据,该层数据是由n行m列的二维规则格网构成,再获取与该数据格式一致的n行m列的海陆分界数据,海陆分界数据包含与其相对应的二值数据,每个像元都引用相同的地理位置,海陆分界二值数据中0代表其他,1代表海洋,利用海陆分界数据对原始数据做叠加分析,分离出海洋区域数据。The step 1) includes: reading out a layer of data to be drawn isolines from a multi-layer and multi-variable marine meteorological raw data file, the layer data is composed of a two-dimensional regular grid of n rows and m columns , and then obtain the sea-land boundary data with n rows and m columns consistent with the data format. The sea-land boundary data contains the corresponding binary data, and each pixel refers to the same geographical location. 0 in the sea-land boundary binary data represents other , 1 represents the ocean, using the sea-land boundary data to do overlay analysis on the original data, and separate the ocean area data.

所述的步骤2)包括:设定一个判断噪点的阈值,遍历数据中的每个像元,若当前像元的数值f(i,j)与周围相连的八个像元的方差σ2减去整体的方差大于给定的阈值,则认为该像元为噪点,该方法可用以下公式表示:The step 2) includes: setting a threshold for judging the noise, traversing each pixel in the data, if the value f(i, j) of the current pixel is subtracted from the variance σ 2 of the surrounding eight connected pixels remove the overall variance is greater than a given threshold, the pixel is considered to be a noise point, and this method can be expressed by the following formula:

式中:gl为f(i,j)点周围邻点的数值;In the formula: g l is the value of adjacent points around f(i, j) point;

当确认某像元为噪点时,用以下公式计算的结果替换原值,When it is confirmed that a pixel is a noise point, replace the original value with the result calculated by the following formula,

式中:f′(i,j)为像元的新亮度;P为该像元是噪点的概率,In the formula: f′(i, j) is the new brightness of the pixel; P is the probability that the pixel is a noise point,

经以上校正后的海洋区域数据可以得到海洋区域有效数值范围。The ocean area data after the above correction can obtain the effective numerical range of the ocean area.

所述的步骤3)包括:得到整体数值范围,再去除海洋区域的计算结果,以此得到其他区域的数值范围;海洋区域数值范围QO=[minO,maxO]可以将其他区域数值范围分为两个部分,上界QL1=(minL1,maxL1]和下界QL2=[minL2,maxL2),它们是全部区域的范围QA=[minA,maxA]的一个划分;The step 3) includes: obtaining the overall numerical range, and then removing the calculation result of the ocean area, so as to obtain the numerical range of other areas; the numerical range of the ocean area QO=[minO, maxO] can divide the numerical range of other areas into two parts, upper bound QL 1 =(minL 1 , maxL 1 ] and lower bound QL 2 =[minL 2 , maxL 2 ), they are a division of the range QA=[minA, maxA] of the whole area;

QA=QL1∪QO∪QL2 (3)QA=QL 1 ∪QO∪QL 2 (3)

式中QL1、QO与QL2两两交集都为空;In the formula, the intersection of QL 1 , QO and QL 2 is empty;

若其他数值全部大于海洋区域,则QL1为空集,若其他数值全部小于海洋区域,则QL2为空集。If all other values are greater than the ocean area, then QL 1 is an empty set, and if all other values are less than the ocean area, then QL 2 is an empty set.

所述的步骤4)包括:对于求出的海洋区域和其他区域的数值范围,构建间隔表设置各个区域不同疏密的间隔,间隔表区域字段分为兴趣区域和其他区域,不同区域的间隔设置原则不同,兴趣区域间隔较小,对应的等值线也较密,其他区域间隔相对较大,绘制的等值线也较稀疏;同一类区域因为数值范围的不同设置不同间隔,所述的数值范围关注的是范围差所属的区间,海洋区域的数值范围差为maxO-minO。Described step 4) comprises: for the numerical range of the marine area and other areas of seeking, build interval table and set the interval of different densities in each area, interval table area field is divided into interest area and other areas, the interval setting of different areas The principles are different, the interval of the interest area is small, and the corresponding contour lines are also relatively dense, while the intervals of other areas are relatively large, and the contour lines drawn are also relatively sparse; the same type of area has different intervals due to different value ranges, and the stated value The range focuses on the interval to which the range difference belongs, and the numerical range difference of the ocean area is maxO-minO.

所述的步骤5)包括:通过步骤4)构建的间隔表的映射,得到以下间隔设置,海洋区域数值范围间隔QIO=[minO,intervalO,maxO],其它区域数值范围上界QIL1=(minL1,intervalL1,maxL1]和下界QIL2=[minL2,intervalL2,maxL2),合并海洋区域和其他区域的间隔,得到整体区域的间隔QIA,Described step 5) comprises: by the mapping of the interval table that step 4) builds, obtains following interval setting, marine area numerical range interval QIO=[minO, intervalO, maxO], other area numerical range upper limit QIL1=(minL 1 , intervalL 1 , maxL 1 ] and the lower bound QIL2=[minL 2 , intervalL 2 , maxL 2 ), combine the intervals of the ocean area and other areas to obtain the interval QIA of the overall area,

QIA=QIL1∪QIO∪QIL2 (4)QIA QIL1∪QIO∪QIL2 (4)

式中QIL1、QIO和QIL2两两交集都为空。In the formula, the intersection of QIL 1 , QIO and QIL 2 is empty.

所述的步骤6)包括:利用MATLAB批量读取数据,调用MATLAB等值线绘制指令contour或contourf,将合并后的间隔QIA应用于该指令,实现自动批量绘制。The step 6) includes: using MATLAB to read data in batches, calling the MATLAB contour drawing command contour or contourf, and applying the combined interval QIA to the command to realize automatic batch drawing.

实施例:Example:

(1)利用海陆分界数据对等值线原始数据做叠加分析,分离出海洋部分的数据(1) Use the sea-land boundary data to do overlay analysis on the original data of the contour line, and separate the data of the ocean part

以2013年5月23日12点0时次的印度洋区域表明气压数值预报产品为例。经度范围30°E~125°E,纬度范围20°S~30°N,分辨率为476*251。通过海陆分界数据的叠加分析,分离出海洋和陆地部分数据。图2为陆地区域表面气压数值预报产品数据的统计图,对该数据的分析可知,陆地区域的气压值范围为600-1100百帕,其分布成锯齿形,从850-1020区间连续有几个峰值,向两边逐步递减。图3为海洋区域表面气压数值预报产品数据的统计图,海洋区域的气压值集中在1000-1020区间,其余区间只有少量的噪点。Take the numerical forecast product of apparent pressure in the Indian Ocean region at 12:00 on May 23, 2013 as an example. The longitude range is 30°E~125°E, the latitude range is 20°S~30°N, and the resolution is 476*251. Through the overlay analysis of the sea-land boundary data, the ocean and land data are separated. Figure 2 is a statistical chart of the surface air pressure numerical forecast product data in the land area. The analysis of the data shows that the air pressure value in the land area ranges from 600 to 1100 hPa, and its distribution is in a zigzag shape, with several consecutive intervals from 850 to 1020 peak, gradually decreasing towards both sides. Figure 3 is a statistical chart of the surface pressure numerical forecast product data in the ocean area. The air pressure values in the ocean area are concentrated in the range of 1000-1020, and the rest of the range has only a small amount of noise.

(2)采用八邻点法去除海洋区域数据的噪点,获取有效的数值范围(2) Use the eight-neighbor point method to remove the noise of the data in the ocean area to obtain an effective value range

设定判断噪点的阈值为1,遍历数据中的每个像元,若当前像元的数值f(i,j)与周围相连的八个像元的方差σ2减去整体的方差大于给定的阈值,则认为该像元为噪点。经校正后的海洋区域数据可以得到海洋区域有效数值范围。Set the threshold for judging noise to 1, traverse each pixel in the data, if the value f(i, j) of the current pixel is connected to the variance σ 2 of the eight surrounding pixels minus the overall variance If it is greater than a given threshold, the pixel is considered to be noise. The corrected ocean area data can obtain the effective numerical range of the ocean area.

(3)根据海洋区域的有效数值范围得到全部区域的一个划分(3) Obtain a division of the entire area according to the effective numerical range of the ocean area

计算得到整体数值范围为600-1100百帕,海洋区域范围为1000-1020百帕,以此得到全部区域的一个划分为[600,1000]∪(1000,1020)∪[1020,1100]。The calculated range of the overall value is 600-1100 hPa, and the range of the ocean area is 1000-1020 hPa, so that a division of the whole area is [600, 1000]∪(1000, 1020)∪[1020, 1100].

(4)利用专家经验分别构建海洋区域和其他区域的间隔表,设置间隔(4) Utilize expert experience to construct the interval table of ocean area and other areas respectively, and set the interval

根据印度洋区域表面气压分布的特定,设计了映射间隔表,如表2所示。According to the specific distribution of surface air pressure in the Indian Ocean region, a mapping interval table is designed, as shown in Table 2.

表1Table 1

(5)合并海洋区域和其他区域的间隔(5) Interval between merged ocean area and other areas

通过该间隔表的映射,可以得到以下间隔设置,海洋区域数值范围间隔QIO=[1000,4,1020],陆地区域数值范围上界QIL1=(1020,40,1100]和下界QIL2=[600,100,1000),以及合并后的整体区域的间隔QIA=[600,100,1000)∪[1000,4,1020]∪(1020,40,1100]。Through the mapping of the interval table, the following interval settings can be obtained, the interval of the numerical range of the ocean area QIO=[1000,4,1020], the upper bound of the numerical range of the land area QIL1=(1020,40,1100] and the lower bound QIL2=[600, 100, 1000), and the interval QIA of the combined overall area = [600, 100, 1000)∪[1000, 4, 1020]∪(1020, 40, 1100].

(6)利用MATLAB批量读取数据,并将5)合并后的间隔应用于MATLAB等值线绘制指令,实现自动绘制(6) Use MATLAB to read data in batches, and apply the merged interval to the MATLAB contour drawing command to realize automatic drawing

调用MATLAB等值线绘制指令contour,将合并后的间隔QIA应用于该指令,实现自动批量绘制。等值线绘制的结果如图4所示。通过不等间距间隔的自动设置,该图在海洋区域有更密集的等值线,它能够展示出海洋区域的气压变化,使得等值线的信息更加丰富;而在次重要的陆地区域,该方法等值线相对稀疏,以降低等值线的混乱程度,能提供更有意义的参考价值。Call the MATLAB contour drawing command contour, and apply the merged interval QIA to the command to realize automatic batch drawing. The result of isoline drawing is shown in Figure 4. Through the automatic setting of unequal intervals, the map has denser contour lines in the ocean area, which can show the air pressure changes in the ocean area, making the contour line more informative; while in the less important land area, the The contour is relatively sparse to reduce the confusion of the contour and provide more meaningful reference value.

本实施例利用海陆分界数据处理兴趣区域,并结合映射表自动匹配陆地和海洋间隔值,有效突出海洋区域要素的变化,可应用于海洋气象专题图的制作等领域。This embodiment uses sea-land boundary data to process the region of interest, and combines the mapping table to automatically match the land and sea interval values, effectively highlighting changes in elements of the sea area, and can be applied to the production of marine meteorological thematic maps and other fields.

Claims (7)

1. a kind of sea land ecotone meteorological contour line automatic drafting method is it is characterised in that comprise the steps:
1) read out, from multilayer multivariable maritime meteorology raw data file, the layer data treating drawing isoline, then obtain The extra large land boundary data consistent with this data form, does overlay analysis using extra large land boundary data, separates and go to sea to initial data Oceanic province numeric field data;
2) set the threshold value judging noise, each pixel in ergodic data, if the numerical value of current pixel and eight being around connected The variance of individual pixel deducts overall variance and is more than given threshold value then it is assumed that this pixel is noise, and this pixel is corrected, Sea area Effective Numerical scope is obtained with this;
3) division of Zone Full is obtained according to the Effective Numerical scope of sea area;
4) build the spacing sheet in sea area and other regions respectively, arranged between regional different density according to spacing sheet Every;
5) merge the interval in sea area and other regions;
6) utilize MATLAB batch to read data, and by step 5) merge after interval be applied to MATLAB isoplethes drawing and refer to Order, realizes automatically drawing.
2. a kind of sea according to claim 1 land ecotone meteorological contour line automatic drafting method is it is characterised in that described Step 1) include:Treat drawing isoline one layer is read out from the multivariable maritime meteorology raw data file of multilayer Data, this layer data is to be made up of the two-dimentional regular grid of n row m row, then obtains the sea of the n row m row consistent with this data form Land boundary data, extra large land demarcates packet containing two-value data corresponding thereto, and each pixel quotes identical geographical position, In extra large land boundary two-value data, 0 represents other, and 1 represents ocean, does overlay analysis using extra large land boundary data to initial data, point Separate out sea area data.
3. a kind of sea according to claim 1 land ecotone meteorological contour line automatic drafting method is it is characterised in that described Step 2) include:One threshold value judging noise of setting, each pixel in ergodic data, if the numerical value f of current pixel (i, J) variances sigma with eight pixels being around connected2Deduct overall varianceMore than given threshold value then it is assumed that this pixel is to make an uproar Point, the method can be represented with below equation:
1 8 Σ l = 1 8 [ g l - f ( i , j ) ] 2 - σ 2 ‾ > ϵ - - - ( 1 )
In formula:L is the numbering of eight adjoint point pixels around f (i, j) point, glPut the numerical value of surrounding adjoint point for f (i, j);
When confirming that certain pixel is noise, replace initial value with the result that below equation calculates,
f ′ ( i , j ) = ( 1 - P ) f ( i , j ) + P [ 1 8 Σ l = 1 8 g l ] - - - ( 2 )
In formula:F ' (i, j) is the new brightness of pixel;P is the probability that this pixel is noise,
Sea area data after above correction can obtain sea area Effective Numerical scope.
4. a kind of sea according to claim 1 land ecotone meteorological contour line automatic drafting method is it is characterised in that described Step 3) include:Obtain overall number range, then remove the result of calculation of sea area, the numerical value in other regions is obtained with this Scope;Other subfield value scopes can be divided into two parts, the upper bound by sea area number range QO=[minO, maxO] QL1=(maxO, maxL1] and lower bound QL2=[minL2, minO), they are scopes QA=[minA, maxA] of Zone Full One division;
QA=QL1∪QO∪QL2(3)
QL in formula1, QO and QL2It is all empty for occuring simultaneously two-by-two;
If other numerical value are all greater than sea area, QL1For empty set, if other numerical value are all less than sea area, QL2For Empty set.
5. a kind of sea according to claim 1 land ecotone meteorological contour line automatic drafting method is it is characterised in that described Step 4) include:For the number range of the sea area obtained and other regions, build spacing sheet setting regional not With the interval of density, spacing sheet area field is divided into interest region and other regions, and the interval setting principle of zones of different is different, Interest region interval is less, and corresponding isopleth is also closeer, other interregional every relatively large, the isopleth of drafting is also diluter Dredge;Because the different setting different interval of number range, described number range is concerned with belonging to range differences in same class region Interval, sea area number range difference be maxO-minO.
6. a kind of sea according to claim 1 land ecotone meteorological contour line automatic drafting method is it is characterised in that described Step 5) include:By step 4) mapping of spacing sheet that builds, obtain following interval setting, between the number range of sea area Every QIO=[minO, intervalO, maxO], other subfield value upper range limit QIL1=(minL1,intervalL1, maxL1] and lower bound QIL2=[minL2,intervalL2,maxL2), merge the interval in sea area and other regions, obtain whole The interval QIA of body region,
QIA=QIL1∪QIO∪QIL2(4)
QIL in formula1, QIO and QIL2It is all empty for occuring simultaneously two-by-two.
7. a kind of sea according to claim 1 land ecotone meteorological contour line automatic drafting method is it is characterised in that described Step 6) include:Using MATLAB batch read data, Calling MATLAB isoplethes drawing instruction contour or Contourf, the interval QIA after merging is applied to this instruction, realizes automatic batch and draws.
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