Shapefiles are currently supplied in thirteen types: POINT, ARC, POLYGON, MULTIPOINT, POINTZ, ARCZ, POLYGONZ, MULTIPOINTZ, POINTM, ARCM, POLYGONM, MULTIPOINTM and MULTIPATCH. The polygon and arc layer types contain what ESRI calls multi-part shapes. For instance, a multipart polygon would be the outer boundary and all the interior holes in the polygon. The multiple parts are maintained using the RingStart mechanism.
The POINTM, ARCM, POLYGONM, and MULTIPOINTM shapes contain an additional ``measurement'' value at each vertex. These measurement values are ignored by GeoGateway and lost in the translation process.
The POINTZ, ARCZ, POLYGONZ, and MULTIPOINTZ are three 3D shapes whereas as the POINT, ARC, POLYGON and MULTIPOINT types are 2D (Z always zero). The Z, and M shape types are new in ArcView 3.x.
The MULTIPATCH shape is a special complex type for representing TINs. The tesselation information inherent in the multipatch is lost by GeoGateway, however, all the data points are preserved on read.
The Shapefile attributes are stored in an xBase (.dbf) file which is also supported as a standalone GeoGateway format. Further details on the .dbf translator can be found in the xBase topic.
Shapefiles are produced by ArcView, and Arc/Info. Within Arc/Info use the ARCSHAPE command to export a coverage to a shapefile, or the SHAPEARC command to import a shapefile and build a coverage.
Export of Arc/Info Shapefiles is supported. These files are exported with a type of "SHP".
Only one vector layer may be exported to a single shapefile.
The output filename for the shapefile to be created should have an extension of .shp or .shx. When data is exported, three files are created with the same basename, and the extensions .shp, .shx and .dbf. Together these make a dataset with attributes.
Shapefiles don't have georeferencing, nor are any other datatypes other than vector layers supported. Georeferencing information usable by GeoGateway software is written to an .aux file, but this will not be supported by ArcView, or Arc/Info.
The option value can be used to select a layer type to assign to the created Shapefile. If no options are specified, the system will select either MULTIPOINT, ARC, or POLYGON depending on the nature of the first shape written to the file, or the LAYER_TYPE metadata.
option = "POINT" | each shape is a single point option = "ARC" | each shape is set of polylines option = "MULTIPOINT" | each shape is a set of points option = "POLYGON" | each shape is a set of closed arcs option = "POINTZ" | each shape is a single 3d point option = "ARCZ" | each shape is set of 3d polylines option = "MULTIPOINTZ" | each shape is a set of 3d points option = "POLYGONZ" | each shape is a set of 3d closed arcsNote that it is not currently possible to write shapefiles with MULTIPATCH shapes in them. POINT and POINTZ layers can only contain shapes with a single point. If no layer type is given as an option, one will be selected based on an internal set of rules.
See Also: xBase, FIMPORT, FEXPORT, Rings