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| The Iowa LIDAR mapping project (http://www.iowadnr.com/mapping/lidar/) has an accuracy of +/- 8”. The Iowa DOT GPS project will provide a signal that is +/- 2 cm (or +/- 0.79”). The accuracy of the LIDAR data represents the additive effects of GPS error, soil tillage operations which create a less than smooth field surface, inherrent LIDAR error, etc. If I drove around the road ringing a section of land to create an accurate peripheral boundary map (i.e., +/- 2 cm), could I overlay the LIDAR data on top of the GPS base to create a highly accurate DEM map?
Around here with slops <<2%, soil loss equations are less than useful because one doesn’t lose soil from fields, rain storms only re-distribute it to other parts of the field – with one exception, overland flow of water into open tile intakes. Water flowing rapidly down a long gentle grade can still pick up quite a load of sediment. Am involved in a watershed project and would like to see them model that open intake flow. Hence the need for highly accurate DEM data.
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