Converting Geobase Land Cover Data

gregleongregleon Global Mapper UserPosts: 30Trusted User
edited August 2014 in Technical Support
I have GML polygon files of canada land cover data that I want converted to a grid format like asci grid or similar. I found a thread that recommended coloring polygon areas based on land cover code. I used a palette that only had the R value of RGB defined for each palette id(23 ids), I set the R value to the land cover type code which range from 0-233. I then exported a single band BIL file(r band), then reimport that BIL and click yes that it is Elevation data. The file imports but the R values are not imported correctly as terrain values like it should (i have used this method to convert USGS Land cover data in a similar way and it imports the R values correctly). The elevation goes from -45 to 122. I can't figure out where these numbers are coming from...any reasons you can think of?

Comments

  • Josie_BMGJosie_BMG Global Mapper User Posts: 71
    edited July 2014
    Hi Gregleon, Can you send a copy of the BIL file that you created to geohelp@bluemarblegeo.com, so that we can take a look at the data?

    I have outlined a workflow below to convert area features to an elevation grid. The process does not involve importing and exporting and will work if you want to have a single elevation value for each polygon.

    First go through and add elevation attribute data to each polygon by selecting the area feature with the Digitizer tool, right click on in the workspace, and then select EDIT – Edit Area Feature. In the Features Attribute section of the dialog, click the add button, type Elevation for the Attribute Name and add the land cover value in the Attribute Value field, then click OK.

    The next step is to go to the Overlay Control Center, right click on your polygon layer and select GRID – Create Elevation Grid From 3D Vector Data…, then click OK. Next go to the File menu, choose Export Elevation Grid Format... and select the Arc ASCII Grid format.

    I am not entirely sure that this is what you are looking for, so please send more information to clarify.

    Thanks!
    Josie
  • gregleongregleon Global Mapper User Posts: 30Trusted User
    edited August 2014
    I submitted the bil file to your email
  • Josie_BMGJosie_BMG Global Mapper User Posts: 71
    edited August 2014
    Hi Gregleon, We have not received the file. Did you send it to geohelp@bluemarblegeo.com? Can you try sending it again?

    Thanks!
    Josie
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