Tom's Blog

Sunday, February 27, 2011

New GIS-based management map now available

I'm gradually learning the intricacies of ArcGIS, and I have now used the new 2010 Dane County air photo as a basis for creating a new management map of Pleasant Valley Conservancy. This map is available at this link. (Be sure to refresh your browser when you access the link.)

The version provided here is in letter-sized landscape format, which is half-sized of the version I created in GIS. The version I drew was in tabloid format, and I printed versions on 11 X 17 inch paper for lamination. When we get our new kiosk installed this summer, I'll post a large-sized version there.

The 2010 georeferenced air photo is provided free by Wisconsinview.org and is the key to this management map. Although anyone can download this photo, it is unfortunately in MrSID format and hence not viewable in Photoshop or any normal photo program. MrSID (pronounced Mister Sid) is an acronym for multiresolution seamless image database, and is a file format developed by LizardTech for encoding georeferenced raster graphics such as orthophotos. If you don't have ArcGIS, a MrSID viewer can be downloaded free from the U.S. Library of Congress. (The Library of Congress uses the MrSID format for its maps.) Wisconsinview.org is a free web site run through the UW-Madison Space Science and Engineering Department.

We make considerable use of our management map, since it helps us keep track of where we have worked. Even with GPS, it is very useful to be able to use the management units to help us close in on an area we are working on. After a while, these management unit numbers become like old friends.

The advantage of the new version is that it is more accurate than the older one (which was based on an air photo but without the Waypoints and Tracks positions). For instance, the positions of the fire breaks, roads, overlooks, and parking places are based on GPS coordinates.

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