gis - 局部投影的 WKT 等价物

Question

我正在尝试使用 gdal 从多个局部坐标系投影一些基本形状。 ArcGIS 支持这些坐标系，但最终我只是厌倦了使用 gdal(和 proj4)将这些几何图形转换为基本纬度/经度(EPSG:4326)。这是 gdalsrsinfo 返回的内容:

PROJCS["mylocalgrid",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Local"],PARAMETER["False_Easting",20289.634],PARAMETER["False_Northing",14781.765],PARAMETER["Scale_Factor",1.000179],PARAMETER["Azimuth",0.0],PARAMETER["Longitude_Of_Center",-109.675257803],PARAMETER["Latitude_Of_Center",32.9599048 58],UNIT["Foot_US",0.3048006096012192]]

如果我尝试使用 ogr 来转换点 shapefile，我会收到以下错误:

ERROR 6: No translation for Local to PROJ.4 format is known.
Failed to create coordinate transformation between the
following coordinate systems.  This may be because they
are not transformable, or because projection services
(PROJ.4 DLL/.so) could not be loaded.
Source:

proj4 是否支持局部坐标系？有什么建议我应该用于 PROJECTION 参数吗？

谢谢。

Answer 1

查看 Local Cartesian Projection 的 ArcGIS 文档，它说“此 map 投影与 Orthographic 相同”。因此，对于 PROJECTION 参数，将 "Local" 替换为 "Orthographic"，它应该可以工作。这是 Python 中的一个片段，向您展示了正在发生的事情:

from osgeo import osr
p = osr.SpatialReference()
p.ImportFromWkt('PROJCS["mylocalgrid",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Orthographic"],PARAMETER["False_Easting",20289.634],PARAMETER["False_Northing",14781.765],PARAMETER["Scale_Factor",1.000179],PARAMETER["Azimuth",0.0],PARAMETER["Longitude_Of_Center",-109.675257803],PARAMETER["Latitude_Of_Center",32.9599048 58],UNIT["Foot_US",0.3048006096012192]]')
print(p.ExportToProj4())

显示 PROJ.4 字符串:

+proj=ortho +lat_0=32.959904858 +lon_0=-109.675257803 +x_0=6184.292811785623 +y_0=4505.490982981965 +ellps=WGS84 +units=us-ft +no_defs 

当然，测试一下看它是否有效是个好主意。