btw NHD data tends to be too large for JOSM to handle… my one complaint about JOSM, I feel it could be more memory efficient. Qgis can be used to process and extract large datasets, just split them up into several files per state. (You also need to merge the source files.) But it’s totally worth the pain, because you get a lot of rich, high resolution data.
Depending on where you live, your state or city might also have open datasets available.
Okay what is nhd and ngs? When I’m horny for aerial imagery, I’m usually browsing Landsat and Sentinel archives.
National hydrography dataset and national geodetic survey (but I actually meant USGS, they provide a lot of data, their map viewer is a good introduction).
Oh thank you very much. Yes, the map viewer I often use, although I’ve only touched Landsat and Sentinel imagery.
btw NHD data tends to be too large for JOSM to handle… my one complaint about JOSM, I feel it could be more memory efficient. Qgis can be used to process and extract large datasets, just split them up into several files per state. (You also need to merge the source files.) But it’s totally worth the pain, because you get a lot of rich, high resolution data.
Depending on where you live, your state or city might also have open datasets available.