GeoPandas.to_crs（）不能作为函数的一部分工作，但可以在独立程序中工作

Question

我试图将一个由点组成的GeoJSON层从EPSG:4326重新投影到EPSG:3857。当我在一个独立的程序中运行下面的代码时（如下所示），输出与预期一样。

geojsonSaveDir = 'path_to_input_file'
firePoints4326 = gpd.read_file(geojsonSaveDir)
firePointsReproject = firePoints4326.copy()
firePointsReproject['geometry'] = firePointsReproject['geometry'].to_crs(3857)
print(firePoints4326['geometry'].head())
print(firePointsReproject['geometry'].head())
firePointsReproject.crs = from_epsg(3857)
reprojectSaveDir = geojsonSaveDir.replace('.geojson', '') + '_3857'
firePointsReproject.to_file(reprojectSaveDir)

上述代码的输出为：

0    POINT (-61.56000 -11.96000)
1    POINT (-61.58000 -11.96000)
2    POINT (-59.21000 -11.66000)
3    POINT (-59.23000 -11.66000)
4    POINT (-51.55000 -11.28000)
Name: geometry, dtype: geometry
1    POINT (-6855054.243 -1341156.488)
2    POINT (-6591227.050 -1307038.377)
3    POINT (-6593453.440 -1307038.377)
4    POINT (-5738519.750 -1263874.866)
Name: geometry, dtype: geometry

然而，当我使用完全相同的代码创建一个函数时，输出是EPSG： 3857中的shapefile，其中所有点的坐标都是0.00000, 0.00000。大多数时候，这甚至不会在QGIS中显示。此函数的输入参数是要重新项目的GeoJSON文件的路径。我对输出是shapefile没意见，但就是不明白为什么重新投影在以前不会这样工作。

def pointReprojector(geojsonSaveDir):
firePoints4326 = gpd.read_file(geojsonSaveDir)
firePointsReproject = firePoints4326.copy()
firePointsReproject['geometry'] = firePointsReproject['geometry'].to_crs(epsg=3857)
print(firePoints4326['geometry'].head())
print(firePointsReproject['geometry'].head())
firePointsReproject.crs = from_epsg(3857)
reprojectSaveDir = geojsonSaveDir.replace('.geojson', '') + '_3857'
firePointsReproject.to_file(reprojectSaveDir)
return reprojectSaveDir

其输出为：

0    POINT (-61.56000 -11.96000)
1    POINT (-61.58000 -11.96000)
2    POINT (-59.21000 -11.66000)
3    POINT (-59.23000 -11.66000)
4    POINT (-51.55000 -11.28000)
Name: geometry, dtype: geometry
0    POINT (0.00000 0.00000)
1    POINT (0.00000 0.00000)
2    POINT (0.00000 0.00000)
3    POINT (0.00000 0.00000)
4    POINT (0.00000 0.00000)
Name: geometry, dtype: geometry

我对GeoPandas相当陌生，所以任何帮助都将不胜感激。如果需要更多信息，请告诉我。

Answer 1

请尝试使用此选项：

def pointReprojector(geojsonSaveDir):
    firePoints4326 = gpd.read_file(geojsonSaveDir)
    firePointsReproject = firePoints4326.copy()
    firePointsReproject['geometry'] = firePointsReproject['geometry'].to_crs('epsg:3857')
    print(firePoints4326['geometry'].head())
    print(firePointsReproject['geometry'].head())
    #firePointsReproject.crs = from_epsg(3857)
    reprojectSaveDir = geojsonSaveDir.replace('.geojson', '') + '_3857'
    firePointsReproject.to_file(reprojectSaveDir)
    return reprojectSaveDir

请注意，您不需要在重新投影后设置CRS。这就是为什么我评论了那句话。另外，我看到您对to_crs功能使用了两种不同的输入样式（to_crs（3857）和to_crs（epsg=3857））。只要坚持这种输入方式，你就不会出错：到crs（“epsg:3857”）。

我用下载的GeoJSON尝试了上面的代码，结果很好——生成的shapefile在QGIS中非常完美。