arcpy.geometry __geo_interface__和AsShape（）函数：精度和孔的损失

我正在将arcpy几何序列化为geojson，以便以后可以将它们“水化”为几何形状，并且在周期中遇到两个问题：

问题1：精度

    R0 = arcpy.SearchCursor(self.shpTest, "FID=0").next().getValue("Shape")          
    geojson = R0.__geo_interface__                        
    R1 = arcpy.AsShape(geojson)
    self.assertTrue(R0.equals(R1)) <<< THIS FAILS

如果我检查字符串表示形式，则坐标略有变化：

    geojson2 = R1.__geo_interface__
    print geojson
    print geojson2  

    {'type': 'Polygon', 'coordinates': [[(442343.5516410945, 4814166.6184399202), (442772.17749834526, 4811610.7383281607), (441565.67508534156, 4811499.6131059099), (440772.50052100699, 4814184.7808806188), (442343.5516410945, 4814166.6184399202)]]}
    {'type': 'Polygon', 'coordinates': [[(442343.55169677734, 4814166.6185302734), (442772.17749023438, 4811610.73828125), (441565.67510986328, 4811499.6130981445), (440772.50048828125, 4814184.7808837891), (442343.55169677734, 4814166.6185302734)]]}

问题2：孔 如果多边形有孔，则geo_interface会产生错误：

    R0_WithHoles = arcpy.SearchCursor(self.shpTest, "FID=0").next().getValue("Shape")          
    geojson = R0.__geo_interface__  <<< generates this ERROR:

    File "C:\Program Files\ArcGIS\Desktop10.0\arcpy\arcpy\arcobjects\geometries.py", line 68, in __geo_interface__
        return {'type': 'Polygon', 'coordinates': [[(pt.X, pt.Y) for pt in part] for part in self]}
    AttributeError: 'NoneType' object has no attribute 'X'

关于如何解决这些问题的任何想法？

OK-好吧，我以为我已经解决了。

从以下位置替换此文件C：\ Python26 \ ArcGIS10.0 \ Lib \ arcpy \ arcobjects \ geometries.py的〜80行：

return {'type': 'Polygon', 'coordinates': [[(pt.X, pt.Y) for pt in part] for part in self]}

为此（或者更简洁，更优雅且功能相同的东西）：

  obj = {"type": "Polygon"}
    coordinates = []
    for part in self:
        _part = []
        for pt in part:
            if pt is not None:
                print pt
                _part.append([pt.X,pt.Y])
            else:
                print "none"
                coordinates.append(_part)
                _part=[]
        coordinates.append(_part)
    obj["coordinates"]=coordinates
    return obj

基本上，他们忘记考虑用零点值标记的形状的甜甜圈。这会吐出良好的geoJson（独立的部分），但是arcpy.AsShape方法会破坏GeoJSON。

此代码：

import arcpy
gj = {
  'type': 'Polygon', 'coordinates': [
   [[-122.803764, 45.509158], [-122.796246, 45.500050], [-122.808193, 45.500109],
      [-122.803764, 45.509158]],
   [[-122.804206, 45.504509], [-122.802882, 45.502522], [-122.801866, 45.504479], 
      [-122.804206, 45.504509]]
   ]
 }

 p = arcpy.AsShape(gj)
 print p.__geo_interface__

输出此：

    {'type': 'Polygon', 'coordinates': [[[-122.8037109375, 45.50927734375],  
    [-122.79620361328125, 45.5001220703125], [-122.80810546875, 45.5001220703125],
    [-122.8037109375, 45.50927734375]]]}

我放弃。;）

更新 漏洞问题已在10.1版中使用以下python块解决：

return {'type': 'Polygon', 'coordinates': [[((pt.X, pt.Y) if pt else None)
                                                    for pt in part]
                                                        for part in self]}