7.5.21: mobi`routes/gps
todo
gis (geographical info systems)
opensourcegis.org
freegis.org
gislounge.com
google openssource autodesk autocad cad
7.5.26: datum theory links
biology.usgs.gov/geotech/documents/datum.html
www.colorado.edu/geography/gcraft/notes/notes.html
. usa`datums include nad 27, and wgs 84 .
7.5.28: aeronautical charts
www.naco.faa.gov
aviationtoolbox.org/rawdata/faasectionals.html
