Sunday, July 12, 2015

New and Updated Lake Maps

The lake wasn't quite there yet Tuesday with about 8" to go and by Thursday about 6" to go but had stopped going up. Rains Saturday along with rains on the way for Sunday and Monday should do the trick. Unfortunately it looks like only one day this week without rain so even if the lake does top off I likely won't get to start depth mapping for another week.

I redid all the maps mostly changing everything to WGS84 Web Mercator so all finished maps will be in that format which is the same format that Google Maps, Bing Maps, Open Street Map and other web based maps use. That means layers can be overlayed on a Google Earth Map.

The maps can be downloaded here. Links to mapping programs on the right ------->

README for maps:

Base Layers NAD83 UTM folder - contains the layers clipped from county sized layers in their original NAD83 UTM CRS (Coordinate Reference System) from the Iowa Natural Resources Geographic Information Systems Library. Also contains 2ft contour Shape file as well as the mask used to clip them from a county-wide Shape file.

Base Layers WGS84 WM folder - This contains the NAD83 layers 'warped' (re-projected) to WGS84 datum and a Web Mercator projection EPSG 3857 (Also known as Spherical Mercator and Pseudo Mercator) These maps have all been processed through GIMP For better color balance and sharpness as well as editing of the LIDAR layer to clean up the old creek and road under the dam as well as the parking lot areas. It's also had the brightness and contrast darkened so as to show up better and not fade out the color as badly when overlayed with a transparent photo or topo map. The base layers all have a .gtf file which is the GeoTIFF header information pulled using GeoTFF Tools. Programs like GIMP and other graphics/photo editing program strip out the Geo information in the header so you have to use GeoTIFF Tools to reinsert the Geo information that calibrates the maps. These are text files and can be viewed in notepad or other programs

Most GPSes use the WGS84 Web Mercator and although many programs such as OziExplorer, and Fugawi can handle re-projection 'on the fly' Google maps, Open Street Map, Bing and other online maps are in WGS84 Web Mercator format and both of my depth mapping packages need WGS84 WM background maps. I recommend the WGS84 WM layers be used for any editing or custom maps you may want to make or if you want to use one as an overlay in Google Earth

Finished Maps folder - All maps in this folder will be in WGS84 WM format. This will hold a variety of finished background and and later depth maps in several formats

Finished Maps sub-folder - Orux Map Tiles -  contains zipped folder tiled maps for OruxMaps (Android). To use just download the free OruxMaps app from the Google Play store and unzip in the default directory. Usable as just a map with about any Android device and those with built-in GPS can make tracks and waypoints to mark and find fishing spots. 

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