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Here are the general steps involved in creating a watershed boundary. You need to work with a raster DEM, not vector contours. This means that you have two options; you can either try to interpolate your contours or you can look for an existing raster DEM of the study area. Most of the interpolation methods contained within ArcGIS's interpolation toolbox ...


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It is possible to create a rough outline of a watershed boundary just using contours. You would pick a location (a "pour point"), usually in the stream channel so you might want to have a streams layer (you could get one like the NHD streams layer) or perhaps there are streams also on the CD. You would start at this one location (of your choosing) in the ...


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My advice for processing your data is to move from contour lines to a raster using Topo to Raster. From there, google ArcMAP watershed tutorial. It is a very common sample exercise in GIS courses. I found 9 course excerpts with that simple query. Another recommendation is to get a trial version of AutoCAD Civil3D and calculate the watershed from a surface ...


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This gets the job done, but I have the feeling there's a better way (probably with ST_Relate). select a.ogc_fid "FID_line_test" ,a.name "Name" ,lp.ogc_fid "LEFT_poly_test" ,rp.ogc_fid "RIGHT_poly_test" from public.line_test a inner join public.poly_test lp on ST_Intersects( lp.wkb_geometry, ...


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The Topology Checker plugin is a good tool if used correctly. You still have to have a fundamental understanding of your data AND you have to make the 'corrections' manually. The plugin will highlight what it thinks are errors. It is up to you to then examine each and make the appropriate decision for you and your data. With 90 000 items in your layer, you ...


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You can do this in SQL using a spatial self join. You don't state which SQL dialect you are using, so this example uses Postgres/Postgis, but it could be easily adapted to Oracle or SQL Server. Assuming a table called buildings, with geometry stored in a column called geom: SELECT a.id, b.id from buildings a, buildings b WHERE ST_INTERSECTS(a.geom, ...


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I would use Python's itertools and a SearchCursor for a very efficient way to find the spatial relationships you are after. You can incorporate the geometry methods overlaps, contains, and equal to get at the geometry properties. Start off by creating a function to better organize the workflow and for repeatability def findOverlaps(x): Open a search ...


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in QGIS, Topology Checker plugin can propably solve your problem


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I have an idea what may work for you. It is going to be based off some assumptions, but it would help narrow down your list of possible identical features. This would not be an automated process, but it would require manually looking at the duplicates. Based off the comments, it seems like the automated tools don't compare attributes so this would help ...



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