shapefile中是否允许使用混合几何类型？

shapefile是否支持混合几何类型（即点和面都在同一文件中）？

可以从官方规范http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf中找到答案。

All the non-Null shapes in a shapefile are required to be of the same shape type.  The
values for shape type are as follows:
Value                                 Shape Type
0                                     Null Shape
1                                     Point
3                                     PolyLine
5                                     Polygon
8                                     MultiPoint
11                                    PointZ
13                                    PolyLineZ
15                                    PolygonZ
18                                    MultiPointZ
21                                    PointM
23                                    PolyLineM
25                                    PolygonM
28                                    MultiPointM
31                                    MultiPatch

Shape types not specified above (2, 4, 6, etc., and up to 33) are reserved for future use.
Currently, shapefiles are restricted to contain the same type of shape as specified above.
In the future, shapefiles may be allowed to contain more than one shape type.  If mixed
shape types are implemented, the shape type field in the header will flag the file as such.

还要注意，点和多点不能保存到相同的shapefile中，而线和折线以及多边形和多面体不能保存到相同的shapefile中。

shapefile不支持混合几何。shapefile由点，折线或多边形组成，但不得超过一个。

有关更多信息，请参见本文：Shapefiles