>>http://terraserver.microsoft.com/default.asp >>This site has recently added aerial photos for the full U.S. >Actually, not, so far as I can tell. True. I noticed that the day after I posted the above false statement. The reason for my assumption was that the U.S. index map used to have a number of "white spaces" on it indicating no map available (including the town where I live). The other day, I noticed that TerraServer.microsoft now has an aerial photo of where I live, and I was pleasantly surprised to see that on the U.S. index the whole map is green. What I later found out, however, is that one shade of green equals "USGS Topographic Map" only instead of a photo. Thanks for pointing out that "100% of the conterminous United States is expected to be completed by the end of 2001." >>After zooming in on your observation location, click "Image >>Information" on the left for a Lat/Long grid. You should be able to >>interpolate to within 0.0001 degrees. I was just on the TerraServer.microsoft site and noticed that they have redesigned it. The commands are now just words at the top instead of buttons to the left. "Image Information" is now "Image Info" and the three words "Relief" (not much good for sat viewers), "Topo", and "Image" appear in a group. Presently, I couldn't get it to call up topo maps for any location (seems like that particular database is unavailable). Instead of clicking on the big map a number of times in order to zoom in on a city, it is quicker to just type a city into the Find box and click GO. A list of available photos and maps will appear for selection. >I'm guessing that those of us who carry around 4 decimal places >may be carrying around a little hubris as well. I've made attempts to zero in on my observing location and have seen three different computer programs that show a delta of +/- 0.0001 between the three in Lat and zero to +0.0001 in Long. The grid lines on the TerraServer.microsoft photo agrees in the same range as these. A borrowed GPS receiver averaged +/- 0.0002 from the map programs. I agree that to 0.0001 degrees is pushing it, but it seems that with a little work we can have confidence within 0.0002 degrees (or about +/- 22 meters in latitude, and about +/- 22*COS(Lat) in Longitude). Ralph McConahy 34.8830N 117.0064W (+/- a couple ten-thousands) 675m (+/- at least 5m) ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Wed Jun 07 2000 - 21:59:23 PDT