Historical topo maps

[Florian]

This looks pretty neat. Historical topographic map scans. Calif isn't online yet but is scheduled to be sometime in fall of 2011 ..

http://nationalmap.gov/historical/

-Florian

[Hikin_Jim]

Very cool!

HJ

[Andy]

This is great, thanks Florian.

[HH8]

So by comparing old ones to present topos, we can find geographic alterations from quake, flood, landslide, etc. There might also be info on the location of buildings and paths that have since become inaccessible.

[Zé]

usgs does have a bunch of historical topos for california. i blogged about it a while ago, in the link you can find a 'kml' file that you can open in Google Earth and it will allow you to pick any available quadrant and overlay it. there was a lot in southern california - specifically san gabriels, but I think there was a few for the San Jacintos although maybe not the most detailed.

http://hikingscience.blogspot.com/2010/02/google-earth-topo-overlay-mapping.html