c# - Mapscript queryByPoint 不返回结果

我有一个用 c# mapscript 制作的动态生成的 map 文件，其定义如下:

MAP
  EXTENT 5.91828 45.63552 5.92346 45.65051
  IMAGECOLOR 192 192 192
  IMAGETYPE png
  SIZE 256 256
  STATUS ON
  TRANSPARENT TRUE
  UNITS METERS
  NAME "GMAP_TILE"

  OUTPUTFORMAT
    NAME "png"
    MIMETYPE "image/png"
    DRIVER "GD/PNG"
    EXTENSION "png"
    IMAGEMODE "PC256"
    TRANSPARENT TRUE
  END

  SYMBOL
    NAME "circle"
    TYPE ELLIPSE
    FILLED TRUE
    POINTS
      1 1
    END
  END

  SYMBOL
    NAME ">"
    TYPE TRUETYPE
    ANTIALIAS TRUE
    CHARACTER ">"
    GAP -20
    FONT "arial"
    POSITION CC
  END

  PROJECTION
    "proj=merc"
    "a=6378137"
    "b=6378137"
    "lat_ts=0.0"
    "lon_0=0.0"
    "x_0=0.0"
    "y_0=0"
    "units=m"
    "k=1.0"
    "nadgrids=@null"
  END
  LEGEND
    IMAGECOLOR 255 255 255
    KEYSIZE 20 10
    KEYSPACING 5 5
    LABEL
      SIZE MEDIUM
      TYPE BITMAP
      BUFFER 0
      COLOR 0 0 0
      FORCE FALSE
      MINDISTANCE -1
      MINFEATURESIZE -1
      OFFSET 0 0
      PARTIALS TRUE
    END
    POSITION LL
    STATUS OFF
  END

  QUERYMAP
    COLOR 255 255 0
    SIZE -1 -1
    STATUS ON
    STYLE HILITE
  END

  SCALEBAR
    ALIGN CENTER
    COLOR 0 0 0
    IMAGECOLOR 255 255 255
    INTERVALS 4
    LABEL
      SIZE MEDIUM
      TYPE BITMAP
      BUFFER 0
      COLOR 0 0 0
      FORCE FALSE
      MINDISTANCE -1
      MINFEATURESIZE -1
      OFFSET 0 0
      PARTIALS TRUE
    END
    POSITION LL
    SIZE 200 3
    STATUS OFF
    STYLE 0
    UNITS MILES
  END

  WEB
    IMAGEPATH ""
    IMAGEURL ""
    QUERYFORMAT text/html
    LEGENDFORMAT text/html
    BROWSEFORMAT text/html
  END

  LAYER
    NAME "Troncons"
    PROJECTION
      "proj=longlat"
      "ellps=WGS84"
      "datum=WGS84"
    END
    STATUS DEFAULT
    TEMPLATE "nofile.html"
    TOLERANCE 100
    TOLERANCEUNITS METERS
    TYPE LINE
    UNITS METERS
    CLASS
      NAME "Troncons"
      STYLE
        ANGLE 360
        COLOR 0 0 255
        SIZE 5
        SYMBOL "circle"
        WIDTH 5
      END
      STYLE
        ANGLE 360
        COLOR 0 0 0
        SIZE 12
        SYMBOL ">"
        WIDTH 1
      END
    END
    FEATURE
      POINTS
        5.91828 45.63552
        5.91876 45.63611
        5.91898 45.6364
        5.91936 45.63701
        5.91952 45.63731
        5.91968 45.63762
        5.91993 45.63825
        5.92003 45.63856
        5.92018 45.63919
        5.92028 45.63983
        5.92031 45.64014
        5.92033 45.64046
        5.92034 45.64077
        5.92034 45.64108
        5.92034 45.64171
        5.92035 45.64234
        5.92035 45.6428
        5.92037 45.6433
        5.9204 45.64394
        5.92046 45.64458
        5.92056 45.64522
        5.92062 45.64554
        5.92069 45.64586
        5.92077 45.64617
        5.92097 45.64679
        5.92122 45.64739
        5.92136 45.64769
        5.92169 45.64828
        5.92207 45.64886
        5.92228 45.64914
        5.92272 45.64969
        5.92321 45.65023
        5.92346 45.65051
      END
    END
  END
END

我尝试 queryByPoint 检索附近的形状的索引。在下面的代码中，我使用固定点而不是通过参数传递的点制作了一个特定的测试函数，因此我确定我使用的点实际上是功能的一部分。就我而言，我使用 mapfile 中包含的唯一特征的第一点。

public string GetTronconId()
    {
        //_map is my dynamically created mapObj
        if (_map != null)
            for (int i = 0; i < _map.numlayers; i++)
            {
                layerObj layer = _map.getLayer(i);
                // Code never pass this point
                if (layer.queryByPoint(_map, new pointObj(5.91898, 45.6364, 0, 0), (int) MS_QUERY_MODE.MS_QUERY_MULTIPLE, 100) == (int) MS_RETURN_VALUE.MS_SUCCESS)
                {
                    int numresults = layer.getNumResults();
                    if (numresults != 0)
                    {
                        layer.open();
                        for (int j = 0; j < numresults; j++)
                        {
                            resultCacheMemberObj resultat = layer.getResult(j);
                            shapeObj shape = null;
                            if (layer.getShape(shape, resultat.tileindex, resultat.shapeindex) == (int) MS_RETURN_VALUE.MS_SUCCESS)
                                return shape.getValue(0);
                        }
                    }
                }
            }

        return null;
    }

我有一个虚拟的 TEMPLATE 集，我什至不必使用容差，因为该点是正确的形状，但 queryByPoint 不断返回给我 MS_FAILURE。从我在网上的搜索来看，一切似乎都很好。任何想法？

最佳答案

好的，第二次尝试:querybypoint 函数需要 map 投影中的查询点，而不是图层的投影。

关于c# - Mapscript queryByPoint 不返回结果，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/2229025/