New answers tagged web-service
I am assuming you mean data sets such as these. It would appear that they use multiple sources and they seem to be credited on the individual pages for each data set/demographic (eg), the ones that arean't credited I assume are owned by esri. Hope that is what you were looking for.
Yes, you can definitely use USGS National map ortho-imagery to extract features, using heads-up digitizing methods (HUD.) The trick here is to work within a projected environment using UTM or State Plane as a coordinate system to ensure fidelity. Another consideration should be the age of the image. Ensure you are working with the most current image possible ...
Orthoimagery from The National Map is technically already digital data. Regardless, you may conduct manual on-screen digitizing with USGS orthoimagery as a base to trace specific entities such as houses and roads. Bear in mind the coordinate system of imagery and the feature class you are doing your tracing with to ensure they match while tracing. Also, ...
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