Hi folks,
We are in the process of starting a new project that has requirements
for the display of street data of major cities on the eastern
seaboard.
What I am looking for is:
o What data is available for the display of city streets (commercial
or otherwise)?
o Can this data be displayed in Grass?
o If the data can't be displayed in Grass is there another GIS package
that will display the data in an X environment?
Thanks,
--
Rajesh Chawla 2411 Dulles Corner Park
E-Mail: raj@gdstech.grumman.com Suite 500
Phone: (703) 713-4170 FAX: 713-4103 Herndon VA 22071
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@magnus.acs.ohio-state.edu
Department of Geography Telephone: (614) 292-2250
The Ohio State University
Columbus, Ohio 43210 Fax: (614) 292-6213