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Without seeing specific screenshot examples of what you are seeing, based on research I would say yes, the DEMs are fine and those structures do exist. I pulled up Google Maps and took a look at the terrain and satellite imagery from some of the counties you list. Armstrong shows them with the greatest frequency and proximity, for example at ...


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DTM is used interchangeably with DEM sometimes, but since you are asking to go from DEM to DTM then you must have something specific in mind. DEM format is normally a raster where each pixel's value represents an elevation. DTM sometimes refers to non-raster formats like a Triangulated Irregular Network (TIN). If that's what you want, you could use the ...


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You can generate new cross sections using Hec-Ras, you draw a line like a center of your river then you need to use the coordinates of your cross sections (I used Covadis software to get them). this video expalin the process https://www.youtube.com/watch?v=VlsTNNIi6Kc


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There are several resources available according to a basic Google search on "Mars GIS data". For instance: USGS Planetary GIS Web Server (PIGWAD, and no I'm not making that up) Mars Open Planetary Data Arizona State University Mars Global Datasets


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You can use the raster package: library(raster) dem = raster.open("a_dem') # plot with R library(rasterVis) plot3(dem) # convert the raster to a matrix (as Volcano) demmat = as.matrix(dem) Now, you can apply the same procedure as in r2stl/demo/Maungawhau.R z = demmat x = 1:dim(demmat)[1] y = 1:dim(demmat)[2] library(r2stl) r2stl(x, y, z, ...


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Have you considered "burning in" the main drainage channel? This is a process which is explained well in another thread here: How to 'burn' a stream network into a DEM layer in ArcGIS 10? It can help to account for common errors in elevation data (like bridges or roads crossing the river). It should force the flow in that area and produce a more ...


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I have to write here, because I have not got reputation for comments. I made vectorization of countours few years ago in ArcMap. There is ArcScan toolbar when I did it. Vectorization, of course, wasn't hundred per cent. You have to then manually edit some lines. In ArcScan toolbar I used Generate Features Inside Area. You can try it if you want. If you ...


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Based on the added information in your comment, I would suggest to use the GRASS module r.in.xyz. There are some issues lately with the QGIS GRASS plugin, so I'd work directly in GRASS, standalone. First, when you start GRASS, you're required to setup the GRASS database, and LOCATION. The LOCATION is defined by the coordinate projection parameters. Make sure ...


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It sounds to be like you have not assigned the nodata values correctly. To correct this, try: Spatial Analyst Tools -> Conditional -> SetNull. Select your raster as the input conditional raster AND the input false raster and type in the “Expression” box: Value < -10 AND Value > 9000 (case and space sensitive). This means: “Set to Null all the points ...


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mmm... its been roughly 2 years, and maybe you already find the solution, but in the main menu is the "raster" submenu. In there is the option "miscellaneous" and, in there, is the option "information". this helped me in finding the min and max value. also, the plug-in "statistic raster pixel" do the trick, but it misses some decimals. Sorry for my ...


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You do not say if you are in academia? If you are then the obvious place to go would be edina and digimap. If you are not then have a look here for free elevation data. Of cause you could go to OS the national mapping agency of the UK and get a 50m terrain model...


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Free of charge i would say: Get either ASTER or SRTM from earthexplorer. Both are available at 1 arc-sec., respectively ~20m vertical rmse.


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To load the imported PostGIS raster into QGIS: First, you need to create a connection to your PostGIS database containing the raster. Then, You can go to Database -> DB Manager -> DB Manager from the system menu. The DB Manager Dialog Box will show. You can expand your database; browse to the raster and right-click on it. Choose "Add to Canvas". ...


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There are some tools that will meet your needs: GRASS GIS r.sunmask tool - which will perform fully automatic shadow cast computation based on DEM. It is based on SOLPOS 2.0 sun position algorithm. Please refer to detailed description on GRASS manual webpage. SAGA-GIS Analytical Hillshading module - this tool will also derive shadow cast but it's not as ...


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You can use gdaldem. I suggest you to have a look on http://blog.thematicmapping.org/2012/06/creating-hillshades-with-gdaldem.html You can can produce hillshade for all the azimut and elevation angles and then combine them together.



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