Wetland Mapping

I found the following Open Source GIS related presentations written by GreenWood map over the past 2 years informative, especially the Parcel Mapping complexities found in Wyoming.

  • Skeletonizing Polygons Using PostGIS
  • Cartography and Topology
  • Parcel Mapping WyGEO Meeting
  • Simplifying Geomoetries Using Open Source Tools

The presentations are available on the Greenwood website.

Searching for information on why PostGIS may be be a better option for storing raster data, I came across a presentation "Advanced spatial analysis with PostGIS" by Pierre Racine from the FOSS4G conference earlier this year. The presentation as a whole is chock full of intriguing ideas and the summary below sealed the deal for me on using PostGIS for large raster data sets.

In summary:

Why store raster in the database?

  • One simple language for everything: SQL
  • Many raster functions are similar to vector ones...Complex spatial analyses can be done with a single SQL query.
  • Raster/Vector interaction -Your vector data are normally already in the database...
  • Performance Analysis processing is generally faster on tiled raster coverage.
  • Data volume - You can work on TB raster coverages without much problems.
  • You can even keep the raster’s data outside the database... ...and use them transparently inside the db with SQL
  • Only metadata are stored inside (extent, SRID, pixel type, nodata) Pixel values area read from the referenced files via GDAL.
  • raster2pgsql –R option
  • Through Stumbleupon, I found a list of 60 free online Computer Sciences courses one of which is Advanced Topics in GIS provided by UC Santa Barbara.

    The course description is as follows:

    "A series of intensive lab sessions focused on specific computational languages (e.g., Python, R, shell) and tools (e.g., GDAL/OGR, InVEST, MGET, ModelBuilder) applied to the spatial analysis of environmental problems." and reviews Python Programming, the Open-Source QGIS program, Google Earth and Leaflet.

    Subcategories

    A category for Low Cost Mapping Ideas

    Wetlands in the News

    18 May 2024