Suppose I go to the USGS Seamless web site at The National Map Seamless Server Viewer and I want to download the Feb 2006 Color Orthoimagery for Austin, TX covering a box with LL corner at 30.3N, 97.8W and UR corner at 30.4N, 97.7W. (Around 23GB of imagery.) I could divide the area into about 10 smaller areas and use the Define Download Area by Coordinates button to request each of those, and (with the download size limit set to 250MB) download the whole box in 60 pieces. But that'd be sorta tedious. Does Global Mapper offer some automated way to download the data? If not, is there some easy way (maybe with a batch file or a simple VBscript or something similar) to automate the downloading (on a PC running WinXP and using Internet Explorer) that wouldn't require buying any additional software?
There is a WMS server with some of the USGS UrbanArea data. If you use the File->Download Online Imagery menu command and add a new WMS source with the URL http://ims.cr.usgs.gov/servlet/com.e...DC_Ortho_Urban (use the default service name of 'WMS'), you should get a list of available cities. I didn't see the 2006 Austin data, but there was some very high resolution (0.15 m) Austin data from 2003 that I tried out and it worked great.
I'm guessing that Google Earth just has the entire data set locally and host the data themselves. I think there are some places where you can get various states via WMS, but I have yet to find a single site with all of the NAIP data available through a single WMS. If anyone finds that it would be great! Then it could be added as a built-in source in Global Mapper.
I'm not sure exactly how the USGS is hosting the data for their viewer. In their help they listed a URL for an ArcGIS server plugin, but that doesn't really help non-ESRI users. I couldn't find any mention of a WMS source for the consolidated data. All that I've been able to find is various WMS sources from different states for the NAIP, but nothing all in one place.