Heya guys. I want to import NWI data in Alaska. I’m pretty sure this forum post is supposed to be the first step I’m taking so uhm here I am I guess. This data has been imported in Maryland before so I think proposing this is going to be doable. If I’m missing a step, or you have any questions please tell or ask me (:
It also seems to not be too bad of a source for river areas and ponds/lakes. Albeit that rivers can be very outdated as the earliest data is from the late 70s
You’re in the right place. Asking here is a good first step in the import process.
That’s quite outdated! How does NWI compare with 3DEP in freshness and resolution? Alaska is a vast expanse, so we need to be careful not to bring in lots of data with known issues without a realistic chance of anyone coming around to investigate it. I’d naïvely expect the problem to be compounded quite dramatically by climate change…
I don’t think the river area data is really of use no. I’m mostly just bringing it in for potential discussion. And if too old of data would be heavily disliked, the map viewer can show the source year too! The 3DHP data looks pretty good too but for now I don’t have interest in adding waterways (:
If I’m reading this page correctly, what we imported was a Maryland Department of Natural Resources dataset that happened to use the same classification system as the NWI. So this dataset from USGS ostensibly follows the same standards but might have other more subtle differences. Just in case, a heads up to @ElliottPlack who worked on that Maryland import.
Since this is a work of the federal government, we can dispense with the usual investigation into distribution rights. The next step would be to document on the wiki any processing steps you need to take in order to prepare the data for OSM, such as converting coordinate reference systems or datums, translating attributes to tags, or dropping certain layers (like the waterways).
I won’t be able to reply for a bit so I’ll reply when I have time after this weekend :P
Alright. I’ll write a wiki page. Would you have knowledge of how to prepare data? I’m not tech that savvy /: I wouldn’t even know how to import the data after that XD
Thanks for posting the page. I must admit that I’m well out of my element when it comes to the Cowardin wetland classification, so I wouldn’t know whether the proposed mapping to OSM elements is reasonably accurate. I’d suggest finding a mapper who knows more about wetlands to weigh in.
Data from Gates Of the Arctic National Park will have their geometries replaced as these were manually added with NWI data. Already existing wetlands will all be checked to see if it’s possible to replace geometries, or they have to be deleted. Inside populated areas, everything will also be checked to see if it’s even possible to add data there, and if it is that it will not overlap landuse.
Can you elaborate on the situations where existing data will be deleted? Are they situations where the existing element is completely at odds with what’s in aerial imagery, or something beyond that?
I’m mostly familiar with preparing some common kinds of imports like buildings and boundaries. Wetlands are a whole ’nuther topic for me. One of the challenges I can foresee is ensuring that adjacent polygons are connected to each other in OSM, or maybe not if it’s inappropriate in some cases. QGIS can help you process the shapefile, and JOSM’s Open Data plugin makes it possible to open the shapefile natively and transform it to OSM tagging standards.
Can you elaborate on the situations where existing data will be deleted? Are they situations where the existing element is completely at odds with what’s in aerial imagery, or something beyond that?
If there is any overlap between to be imported data and pre-existing data I will see if I can put them together or if I will delete the already existing data, not import there or see what else. Data which is not in areas where there will be imported will stay untouched.
National Wetlands Inventory (NWI) is from the United States Fish and Wildlife Service and is mostly based on aerial photograph interpretation. United States Geological Survey has their National Hydrologic Dataset (NHD) that includes wetlands and waterways and is mostly based on DEM modelling of Shuttle Radar Terrain Mapping (SRTM) data. Synthetic Apeture Radar is being used for the next round of USGS 3DEP for Alaska (CONUS is airborne lidar), for a 2m ground-accuracy goal. The next update to USGS NHD-HRplus is supposed to be based on the 3DEP DEM data- apparently the first contracts have been let out for the hired gun GIS schmucks to chew through the 3DEP data and produce the next-gen NHD. And the USDA Natural Resources has their own wetland classification/delineations in the National Cooperative Soil Survey. Its wetland madness in terms of federal GIS data.
The NWI itself also says it isn’t attempting to define wetlands but I’m sure it’s accurate enough. Do you think messaging the Maryland importer on how he imported it and possibly help on the wiki page would be a good idea?
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