Tuesday, July 15, 2014

Preliminary Depth Maps

We have a new lake here just northeast of Davenport that is slowly filling right now called Lost Grove Lake. It's been 25+ years in the making but it's a well designed lake within a well managed Watershed to keep silt and fertilizer runoff from getting into the lake which will be 350 acres and 3 miles long when full. I plan on making detailed depth, structure and 3D depth maps of the lake but still need a preliminary map and background maps. The 3 base maps were downloaded as geotiff's in 6 parts each from the Iowa Geographic Map Server and 'stitched' together using the OziExplorer Map Merge program and I recalibrated them using Geotiff Tools. Here are the 3 base maps as uncalibrated half size JPEG's.

The Topo Map Layer

The Photo Map Layer

The LIDAR Layer

From the Topo and Photo layers I was able to derive this Lake Depth overlay, the black areas surrounding the lake are really transparent

I can then overlap this layer on top of the Photo and Topo layers and get these maps

And finally by using the LIDAR layer as the base, changing the transparency of the Photo and Topo layers to 65% and then overlaying the Lake layer I get the following two maps

The next layer I am going to make is denoting all the structure both natural and manmade. By using Geotiff layers I can edit a layer without upsetting the geo-referencing or upsetting the other layers. Then I can 'mix and match' them to make nice Geotiff calibrated maps that are importable/convertible to most GPS navigation and mapping software without the need for hand calibration

Since Blogger nor any web photo viewer can do these justice by displaying them in full resolution I've got them shared on my Google Drive. There are half and full size JPG's of maps in this post plus the 4 full sized TIF's that have the geotif header and should work in any GIS or GPS mapping software that accepts or imports geotif's

Geotiff & JPG Layers.zip

More to come ......

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