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Louisiana Unified Program for a Digital and Analog Technology Environment “La UPDATE” presented by James E. Mitchell, Ph. D. Department of Transportation & Development, IT GIS Manager to the Louisiana GIS Council April 2006 (Updated February 2011)
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In the Beginning… USGS made paper maps… … and they were good Then there was GIS… …and we digitized those maps Now… …The Database Makes the Maps!
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The Current Status of Paper Maps Updated January 2012
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How Up to Date are Louisiana’s Maps? All paper maps are 6 years or olderAll paper maps are 6 years or older 97% of paper maps are 10 years or older97% of paper maps are 10 years or older 77% of paper maps are 15 years or older77% of paper maps are 15 years or older 60% of paper maps are 20 years or older60% of paper maps are 20 years or older 37% of paper maps are 25 years or older37% of paper maps are 25 years or older 21% of paper maps are 30 years or older21% of paper maps are 30 years or older Digital map data have never been updated and are older than the paper maps (Updated January 2012)
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GIS Supports All Digital and Analog Activities
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What are the Problems with Our Current Digital Maps from USGS? USGS produced maps cartographically, not using modern digital techniquesUSGS produced maps cartographically, not using modern digital techniques –No maps “edge-match” and features break along map boundaries –It is too expensive to update more than a few maps at a time –Adjacent maps can be produced decades apart Themes on a single map may have been produced decades apartThemes on a single map may have been produced decades apart –Some maps show land surface elevation contours within water features, creating inaccuracies and confusion
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USGS Maps Do Not Edge-match As lines cross map boundaries they do not meet their counterpart on the next map.
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Our Data and Our Coastline The yellow lines are where best-available digital data show the land-water boundary. The image is post hurricane orthophotography. Neither match the maps.
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Where Do We Build Infrastructure? The first step in a project is to estimate the scope of the work. Much of this is done with maps and GIS. The best-available data are labeled as “USGS NHD” and clearly do not match the shoreline on the image. The remaining lines show how GIS-based photo- revision techniques can be used to update the data.
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Bathymetry or Hypsography? USGS maps are comprised of seven “framework themes” (water, elevation, transportation, boundaries, benchmarks, vegetation, and structures). USGS does not update all themes simultaneously. In recent years, USGS has not updated the land surface elevation theme. This map shows how the old elevation contours (brown) lie in the updated water (blue). The thick red lines show the photo-revised locations of the shoreline and other water features from the 2004 orthophotos.
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