|Using Spatial Data with SAS/GIS Software
GIS procedure creates and maintains the spatial databases that are used by SAS/GIS software.
A SAS/GIS spatial database consists
- SAS data sets that contain the coordinates and
identifying information for the spatial features.
- A spatial entry, a SAS catalog entry of type GISSPA
that identifies which SAS data sets contain spatial information. The spatial
entry also stores
A spatial entry alternatively can contain references to
two or more other spatial entries that have been merged into a single spatial
- Composites that define how the variables in the
spatial data are used
- Names of the polygonal indexes that define the
boundaries of area layers for the map
- A lattice hierarchy that defines which features
in the spatial data enclose or are enclosed by other features (the relationships
among the polygonal variables)
- Information about the projection method that is
used for the stored spatial data.
- A coverage entry, a SAS catalog entry of type
GISCOVER that selects a subset of the spatial data that are available for
display in a map.
- One or more layer entries, SAS catalog entries
of type GISLAYER that identify features that have common characteristics and
specify how they are displayed as layers in the map.
- A map entry, a SAS catalog entry of type GISMAP
that specifies which layers from a particular coverage are included in a map.
The map entry also stores
- The names of attribute data sets that are associated
with the map, along with definitions of how the attribute data are linked
to the spatial data
- The name of a SAS data set that contains labels
for map features
- Definitions of GIS actions that can be performed
when map features are selected
- Definitions for map legends
- Values for display and projection
Note: The task of creating new SAS/GIS spatial
databases from spatial data in other formats can also be performed interactively
by using the GIS Spatial Data Importing window.
Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.