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I took the reverse approach to finding peaks, I found the peak pixels first, and am now trying to select those exceeding a certain prominence (as described on peakbagger.com, they appear to manually inspect topos to get their peaks). A solution for finding the single pixel peaks is to use r.terraflow, followed by r.mapcalc looking for the minimum: Flow ...


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Also PCI has a tool for that DSM to DTM.Surface features such as buildings are mostly removed (minimized) by running a DSM2DTM, which searches for local minimum based on a user defined kernel (filter) size.


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My preference is nationalmap.gov, they even have a new bulk download tool that simplifies the process of downloading all the tiles quite a bit.


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I personally prefer http://datagateway.nrcs.usda.gov/ however the max resolution you can download at one time is statewide and I would assume those will be quite large but it is organized well.


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My favorite source of DEM data is at viewfinderpanoramas.org It has STRM data that has been massaged in various ways. I think that should be good enough resolution for what you require.


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If you happen to use QGIS, install the Raster Interpolation plugin, which lets you to extract DEM elevation data and assign it to point layers. Since I think you deal with polygons, you could first generate centroids* (or a representative point for each polygon) for those polygons and use the points to pick elevation data from the DEM. Finally, join your ...


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If you go to the Earth Explorer web site you can download several DEMs. For Nepal they have the 30m AsterGDEM and the 90m Void Filled SRTM. The 1 arc second (30m) SRTM is not available yet (12/12/2014) but I believe it should be ready in the near future


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Theres SRTM data available. See https://en.wikipedia.org/wiki/Shuttle_Radar_Topography_Mission for more information. Note that SRTM hat a ground resolution of approx. 30 or 90 meters ( 1 and 3 arc-seconds, respectively). That is probably the highest-resolution free dataset available. For more detailed DEMs you should contact local Nepali ...


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This code can be used to create a "Hill slope" DEM of just about any number of rows and columns: # Building a fake hillslope # hisllop is 5 rows by 6 columns x <- seq(-15, 15, by=0.01) z <- 1/(1+1.5^-x) plot(z) z <- 150 - (1-z)*5 plot(z) # Doing it by hand - DELETE if needed - JUST HERE AS AN EXAMPLE!!! elev <- c(mean(z[0:500]), ...


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1) Since version 1.10, you can use ogr2ogr (GDAL) to agjust/"georeference" a shapefile with control points or GCPs (as Spatial adjustment in ArcGIS, look at How to georeference a vector layer with control points? or Add ability to transform vectors based on GCPs in ogr2ogr) Example ogr2ogr -gcp 5 -135 0 0 \ -gcp 283 -135 1000 0 \ -gcp 5 278 0 ...


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I can't comment so I'll answer with how I would approach this in ArcMap. Perhaps you could make a similar workflow. Use the extract by mask tool on your DEM with your road lines as the mask. You now have a raster version of the roads with their elevations. Use the slope tool on that to calculate the slopes along your road raster. I did a quick try on ...


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As I messed this up in the comments and cannot edit it now, I'll try again here. You have two options: Split your roads no finer than the resolution of your DEM. As it is now, you have multiple samples (10m apart) for a single pixel (30m x 30m). The more samples per pixel, the greater the relative jump between pixels. Take 2 pixels, 30m x 30m, 1m height ...


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The problem is due to the presence of non-ascii characters in the path of the output file, so you just change the path name to something else that contains ordinary characters (e.g. UTF-8) and try again.


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I am late here, but this question was my entry into the forum as I was researching the same question. I think that the original poster may want to calculate for each cell the height above the first stream cell that would be reached by water flowing from the cell. So the 'nearest stream' is calculated along the downslope flow path, not euclidian distance. ...


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That's a two step process rasterize the building layer to create a raster with the building height information use field calculator to sum up the DEM and building height Note that the two rasters have to be in the same CRS before you can add them up in the field calculator.


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The way I have done this in the past is to convert buildings, forested areas, etc. to a raster (rasterize the polygon using the height column for the raster value, using the same pixel resolution as the DEM). Then merge the two rasters (DEM and rasterized buildings). This will add the building height to the DEM. One thing to note is that you will probably ...



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