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Hello, I am wondering what resources or training are available to learn how to extract land cover data from orthophotography. Almost all of my GIS experience is with vector data, I have never done much with raster data beyond displaying it as a background to a map. I am working with an urban forestry nonprofit right now. A few years ago Davey did a land cover analysis for the city that we have been using data from. There will be new orthophotography flown in the next couple of years, once that's complete we'd like to do another LC to get updated data, what we're most interested in is tree canopy and impervious surfaces. I've done a little looking online to see if there is any instruction or training available. I haven't found much but I may not be looking in the right place or maybe not using the right search terms. If you have any ideas for how to learn how to do this sort of extraction I would appreciate it if you can share them. Or any advice. Thanks.
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12-23-2016
10:24 AM
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Thank you, that seems to have done the trick. I was so stuck in thinking about dividing them I wasn't even thinking about combining. Anyway, that problem's solved. Next one: units. The source data for the land cover are in US_feet. The block groups? Not so much. I don't even see any linear units listed in their properties, and that same lack is in the new union-ed data: As you can see, all that is listed is angular units. And the numeric values are extremely tiny, which is consistent with the block group data but not land cover. I guess I should have checked this beforehand. Any idea what I can do to get the needed measurements?
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01-20-2016
03:24 PM
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Hi. I have a somewhat convoluted questions that hopefully will be aided by my screenshots. I have land cover data (polygons) available for a small city I'm working with. In the example I'm showing the land cover feature is tree canopy cover. I have the area for the whole city, but I would like to break it down into smaller areas, and I am using block groups since we have other data with those boundaries. The first pic (below) shows the canopy cover (in green) and the block group divisions. The boundaries for the land cover don't match up exactly with the block group boundaries: So I'm trying to find out the best way to calculate the area of land cover info within each block group. I'd rather not do a simple clip because there are 24 block groups and I'd rather not have that many separate feature classes. I've looked into maybe doing a split, but my noobishness stops me where it talks about a workspace (part of the syntax). So, does anybody have any ideas on how best to go about this? Or is there a solution to my problem with the split command? thanks in advance!
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01-19-2016
02:55 PM
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