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What Data Have You Been Working With Lately?


Some of the datasets I’ve been working with lately include:

  • NAIP, 1 meter, 4 band imagery – A colleague classified 3.5 county’s worth of NAIP images into between 4-7 categories and handed it to me to reclassify into “trees” and “not trees” pixels. Though I was not asked to do an error analysis, I loathe using classified imagery without a formal error analysis, so I did one. With 20 randomly chosen pixels in each county (since they were classified separately) checked by-eye to see if they were correctly identified or not, we got a 94% concurrence. That is an excellent error rate. Another error-check that should be done, however, is to randomly choose 20 non-forest pixels in each county to determine concurrence since the original error-analysis was heavily weighted toward “tree” pixels given the huge percentage of trees in the study area. That will be one of my next tasks if I have the time to undertake it.
  • NOAA CCAP, 30 meter, landcover – This dataset covers the coastal regions of the U.S. but was problematic for my project’s needs in that it has a “Palustrine Forested” category whereas we wanted to know specifically what type of forest (coniferous, deciduous, mixed) that those pixels represented. The NOAA people were very responsive and sent me the Landsat mosaics that were used to produce each of the four CCAP year’s worth of data (1992, 1996, 2001, and 2006) so that I could mask out those palustrine forested pixels and reclassify them using a supervised classification. While there is very little way to error-test the results because the data are at least 5 years old, some visual assessment of the 2006 results showed a decent amount of concurrence with what we know to be true on-the-ground right now.
  • Regions – I’m currently involved in a fun project involving by-eye digitizing, at a high resolution, some logically drawn regions (some might call these “territories”) based on demographics and existing political boundaries, but weighted more toward demographics and travel corridors when they cross political boundaries. This is a very fun exercise in the sense that it gives a level of geographic awareness that is only possible when immersed in such a task.

So…what data have you been working with lately?

This entry was posted on July 7, 2011, 7:00 am and is filed under Analysis. You can follow any responses to this entry through RSS 2.0. Both comments and pings are currently closed.

  1. #1 by Brian Kelly on July 7, 2011 - 7:39 am

    I’m just getting started with GIS and am interested in using it to create maps of mountain biking trails. I did a few maps using Adobe Illustrator by tracing routes from Google Maps, Google Earth and Garmin BaseCamp, but scaling and aligning the different layers becomes very tedious. And hand tracing contour lines? Ugh.

    So I’ve been taking some ESRI online courses, revisiting my copy of “Desktop GIS” and playing with ArcGIS, Quantum GIS and Cartographica to see which tool works best for me.

    I want to collect GPS routes from riders (including myself) and then convert/revise them into Geodata that includes the trail name, direction (optional), trail type (singletrack, fire road, road) of legal trails and perhaps also highlight technical features on the trails.

    Currently I’m trying this out on the Taconic Hereford Multi Use Area in Pleasant Valley, NY.

    And your book is on my Amazon Wish List, which is why I started following your blog. I’m just trying to make some strides with some free material first to make sure this is a hobby I want to invest in.

    Anyways… you asked :-)

  2. #2 by Gretchen on July 7, 2011 - 10:13 am

    Thanks for sharing your project with us Brian. Hopefully some readers will have ideas for you regarding digitization of bike trails!

  3. #3 by Adam on July 7, 2011 - 11:45 am

    I’ve recently discovered the wonderful world of NOAA’s Raster Navigational Charts (RNC). http://www.charts.noaa.gov/InteractiveCatalog/nrnc.shtml. I’ve downloaded fully georeferenced images of NOAAs nautical charts for the Pacific Northwest coast, and am using them to digitize features to use an a map of PNW Oyster growing regions.

  4. #4 by Amanda Taub on July 7, 2011 - 1:06 pm

    I have been working with Census blocks and population data. I am supporting our Elections staff in the redistricting efforts for County Commissioners and voting precincts. My other project is QA/QC on our addressing points layer. I also have to get back to documenting metadata on all of our layers now that FGDC metadata can be editted and created in ArcGIS 10.

  5. #5 by Gretchen on July 8, 2011 - 7:06 am

    It’d be great to see that map of the Oyster growing regions when you are done Adam!

    Amanda – still working on Census?! What a huge project. And yippee for bringing the metadata back in Arc10 now (I think).

  6. #6 by Dusty Robinson on July 12, 2011 - 2:33 pm

    I have been using NOAA’s Tsunami Inundation DEMs (http://goo.gl/fgSOH)
    We are involved in several bridge scour studies along the east coast and these DEMs include the best topographic and bathymetric data available for coastal areas. Each packaged grid contains a detailed report that includes a description of each data set used in the creation of the DEM. Very helpful if you are working in coastal areas.

  7. #7 by Gretchen on July 12, 2011 - 3:05 pm

    Dusty – nice DEM resource! Thanks for sharing.

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