Can Grass display Street data?

Duane F Marble dmarble at magnus.acs.ohio-state.edu
Wed Sep 1 08:17:06 EDT 1993


The raster or grid data model used by GRASS is quite capable of
displaying street information if an appropriate cell size is selected.
As a rule of thumb, it should be no larger than one-half the width of
the narrowest street. However if one wants to undertake analysis of the
street network (e.g., shortest paths, flows, etc.), the vector data
model is more efficient (see, for example, the NETWORK module in
ARC/INFO).

The major source of public domain street data is the TIGER files of
the U.S. Bureau of the Census. However these do not represent street
centerlines well and are often of doubtful accuracy. A number of
commercial organizations (such as GDT and Etak) sell what they contend
are better quality files. My experience has been that "better" does
not always mean acceptable!
-- 
Duane F. Marble              E-mail: dmarble at magnus.acs.ohio-state.edu
Department of Geography      Telephone: (614) 292-2250
The Ohio State University
Columbus, Ohio 43210         Fax: (614) 292-6213



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