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I am trying to import a vegetation data raster in Esri GRID format from the USDA into QGIS. One file ("w0001.adf") can be added using "add raster", but the attribute table and other info register as error or errors. Using the "ArcInfo/Binary directory" does not work either.

Chris W
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Sosaa
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  • Please ask your question in the title – bugmenot123 Jul 17 '15 at 13:25
  • see http://gis.stackexchange.com/questions/22067/how-can-i-load-adf-files-to-quantum-gis – julsbreakdown Jul 17 '15 at 14:03
  • Thanks for responding. I tried the suggested method, but it does not work. Using the method where you select the director, I always get an error message. Directly loading one adf file (w001001.adf) works but the attributes are not imported that way. – Sosaa Jul 18 '15 at 10:33
  • It is a USDA Thematic raster map of forest ownership types in the US. It is for the whole US but I would like to do is extract the different types of forest ownership by state... if possible. – Sosaa Jul 18 '15 at 17:37
  • http://www.fs.usda.gov/rds/archive/Product/RDS-2014-0002/ – Sosaa Jul 18 '15 at 18:09
  • I failed to include it in my previous message! – Sosaa Jul 18 '15 at 18:09
  • Thank you for responding. I got as far as you did and now I am trying to see if each Forest ownership type can be calculated for each state? Let me know if you have ideas? – Sosaa Jul 20 '15 at 20:51
  • Yes it can, but I'm not sure about exactly how to go about doing it. In ArcGIS you'd use the Zonal Histogram tool but I don't know that QGIS has such a thing. That is probably best asked as a new question. – Chris W Jul 20 '15 at 22:47
  • Please use the edit button beneath your question to revise it with any additional details that people ask for via their comments. Think of comments as being more or less one way, they are temporary, and there to help you improve your question by editing it. – PolyGeo Jul 21 '15 at 00:08

3 Answers3

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The .adf file is one component of an Esri GRID 'file', much like the .shp is one component of a shapefile. The other component files generally aren't or don't need to be accessed individually. If you can load that w0001.adf file and see the raster image, I suspect you're seeing all the data. I opened/added the file in Arc with no issue. In looking at the attribute table for the raster there, there's just a second, coded, numeric value field - you won't see the text strings describing what those coded values are (that info is listed in the metadata).

Chris W
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The data opens with no issue in QGIS 2.8.1. The raster contains only the coded values 1-6. These coded values are described in the metadata:

Six values of ownership:

1 = Federal (Public): Owned by the federal government. FIA Codes 11-13, 21-25.

2 = State (Public): Owned by a state government. FIA Code 31.

3 = Local (Public): Owned by a local government. FIA Code 32.

4 = Family (Private): Owned by families, individuals, trusts, estates, family partnerships, and other unincorporated groups of individuals that own forest land. FIA Code 45.

5 = Corporate (Private): Owned by corporations. FIA Code 41.

6 = Other Private (Private): Owned by conservation and natural resource organizations, unincorporated partnerships and associations, and Native American tribes. FIA Codes 42-44.

There are no other attributes, which means there is no information about what State a cell is in. To extract forest ownership type for each state, you will have to get a US States dataset and use that to analyse the forest ownership data. You should ask a separate question for that.

Community
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user2856
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For those of you coming to this question in 2022 Chris W's and user2856 answers are still relevant in regards to adding the .adf file to see the data however there is now a QGIS plugin funded by NOAA called Raster Attribute Table Plugin that allows you to load the attribute table and stylize your layer by the classes defined in the table.

Baswein
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