Discussion: Five years ago I explored the possibility of undertaking a project to compile and publish a range of topographic map coverage, aerial photographs, and public domain satellite imagery for theGeoZone.com. In the end it proved to be prohibitively costly from the simple perspective of time invested -- quite literally by more than an order of magnitude. So this project was consigned to the "back burner" in 2004.

But revisiting this requirement in September 2009 provided an entirely different outcome. In the intervening time, enter both Google Maps and Microsoft TerraServer with it's access to USGS topographic quadrangle and DOQ (Digital Ortho Quad) "tiles". This project consequently took on an entirely different character following a lapse of five years, today requiring only a single dynamic web page driven by a compilation of map "centerpoints" and other pertinent information which is accessed from theGeoZone.com's server via JSON/AJAX, and post-processed with client-side JavaScript to deliver any one of 86 full compilations of surface maps, 3D terrain, satellite, and hybrid coverage, topographic, and aerial photography -- actually a richer GIS solution than the original project goal.

Solution: The solution for this requirement, which is now published, eventually revolved entirely around the Google Maps API, augmented with "WMS" map overlays which integrate USGS (United States Geological Survey) topographic map tiles and Digital Ortho Quads (aerial photos) from Microsoft's TerraServer. Unlike Google Maps which are based on decimal latitude / longitude pairs, USGS products (usefully but somewhat problematically) employ Universal Transverse Mercator (UTM) coordinate projection. So beyond the mostly original js to deliver the maps, I derived the JavaScript code to convert Lat-Long to UTM from the published work of some GIS specialists, and adapted it to incorporate UTM "centerpoint" data for theGeoZone.com.

Interactive Maps

At this point I've published over 95 Google Maps (API2) with a variety of overlays, markers, polygons, html info windows, and other options, and the only quirk I had to seriously debug was my own error involving JavaScript closures on info windows. As time presents itself, I'll develop the code to put a small-scale canvas of the results below. Meanwhile, production examples of these interactive maps can be seen here on theGeoZone.com's website; and another example which incorporates map markers, area polygons, and information bubbles can be seen at the bottom of the page here.