My subscription to Life expired, but I still have a subscription to Mad.
Thursday, September 21, 2006
Surfin': Tooling Around The Internet
This week's installment of my weekly column, Surfin', is now online. This week, its title is Tooling Around The Internet. Read it if you will and leave your comments here.
Google Earth is also a great tool for searching for addresses, etc, and has excellent addon programs available...I am waiting for an APRS application to be able to put together with it.
Locations on a map shift when you take coordinates from one datum (such as WGS84 which is default on most GPS displays) and plot it on a map with a different datum (such as NAD27 used on many older topographic maps.) The dtaum is the "starting point" for the coordinates and varies based on the mathematical model used to describe the earths surface for the map.
Always check the datums when comparing locations between two systems or you can be off by a few hundred meters.
Google Earth is also a great tool for searching for addresses, etc, and has excellent addon programs available...I am waiting for an APRS application to be able to put together with it.
ReplyDeleteEnjoy your column/blog, look for it regularly.
73
KC9FQE
Locations on a map shift when you take coordinates from one datum (such as WGS84 which is default on most GPS displays) and plot it on
ReplyDeletea map with a different datum (such as NAD27 used on many older topographic maps.) The dtaum is the "starting point" for the coordinates and varies based on the mathematical model used to describe the earths surface for the map.
Always check the datums when comparing locations between two systems or you can be off by a few hundred meters.
See
http://www.colorado.edu/geography/gcraft/notes/datum/datum_f.html
for more details.
That could be the problem between the automated systems you used.
73
Gary, K2GW
Former navigator