Question

我从谷歌地图方向api计算了线串。我将线串转换为GEOSGeometry对象。我需要另一个覆盖所有地点的区域，距离“d＆＃39;来自linestring对象。距离以m，km为单位。 GEOS API提供了GEOSGeometry.buffer（width，quadsegs = 8）来完成二维投影。

但球形模型怎么办呢？它与SRID有关。

from django.contrib.gis.geos import LineString
from django.contrib.gis.geos import GEOSGeometry

directions = maps_client.directions(source, destination)
overview_polyline = decode_polyline(directions[0]['overview_polyline'])

linestring_obj = LineString(overview_polyline)

# FOR 2-D projection
bounding_box = linestring_obj.buffer(width=100) 

# For spherical model
# ???

Answer 1

对于有意义的地理距离（以米为单位），您将始终必须通过投影坐标系，因此我建议您将数据转换为投影坐标系，创建缓冲区并将其投影回来。例如：

# Specify the original srid of your data
orig_srid = 4326

# Create the linestring with the correct srid
linestring_obj = LineString(overview_polyline, srid=orig_srid)

# Transform (project) the linestring into a projected coorinate system
linestring_obj.transform(3857)

# Compute bbox in in that system
bounding_box = linestring_obj.buffer(width=100)

# Transform bounding box into the original coorinate system of your data
bounding_box.transform(orig_srid)

计算包含地理坐标的线串的边界框

1 个答案: