Questions tagged [dem]

For questions about Digital Elevation Models (DEM), Digital Terrain Models (DTM) and Digital Surface Models (DSM)

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36 views

GRASS r.sun returns “ERROR: insol_time and incidout are incompatible options”

I'm trying to measure irradiance on a DEM using the r.sun tool in QGIS 3.6. I have grids for the elevation (EPSG:32735 - WGS 84 / UTM zone 35S), the slope and aspect (EPSG:4326 - WGS 84). I've tried ...
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1answer
74 views

r.surf.area command of GRASS GIS is giving a very small area

I am a beginner to GIS systems and am trying to calculate the surface area of a dem using r.surf.area command of GRASS GIS. The surface area it is giving me is unacceptable as it is very small. It is ...
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38 views

Assessing quality (accuracy and precision) of digital surface model (DSM)?

I have been trying to build digital surface model from stereo satellite images. I do some initial research of it, it looks like I have to go outside and manually measure the height of an object (...
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13 views

Calculating SCS curve numbers using DSM instead of DTM

Are the curve numbers (calculated by SCS Curve number method) through DSM (Digital Surface Model) valid? Most of the SCS curve number studies focus on calculating curve numbers through a DTM (Digital ...
1
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1answer
45 views

Downloading digital elevation model of United States?

I would like to download a digital elevation model of the United States, where can I do this? It doesn't need to be super detailed. But it would be nice, if was clipped at the country borders – ...
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2answers
77 views

Adding slope values to attribute table (QGIS 3)

I have a DEM raster and some points (one .shp for all points) plotted on it. I would like to know if there is a way to add the slope value of the pixel that each point is located in the attribute ...
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0answers
19 views

Losing raster quality when using raster calculator (ArcGIS Desktop 10.5.1)

I'm currently working with DEM rasters that I hillshaded. The data I received contain nodata borders, probably the footprint of the originial mosaic dataset. As I received them separately, I can't ...
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0answers
19 views

Stacking lidar-derived height raster as ancillary data for segmentation in ENVI?

I get a a black and white image after following these steps. Does anyone know why I'm not getting a color aerial image beneath the mask? My setup consists of these steps: I mosaicked several NAIP ...
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0answers
27 views

Basin Delineation using R

I am trying to get the polygon of a basin boundary using R. I got a 7.5 arcsec DEM that I download from this page: https://topotools.cr.usgs.gov/gmted_viewer/viewer.htm I look through a lot of ...
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2answers
168 views

Adjacent DEM color matching in QGIS?

I have four 15 arc second resolutions DEM files (15-C.tif, 15-D.tif, 15-I.tif, 15-J.tif) downloaded from viewfinderpanoramas.org. When I input them in QGIS I noticed that the 15-J.tif layer differs a ...
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0answers
35 views

Limiting sharp drop off of coastal DEM raster where there is no data using QGIS?

I'm stitching numerous tiled DEM's using Build Virtual Raster and then 'Align raster' function within QGIS 3.6 Original DEM has no data for sea area as expected: I get sharp drop off on coastal/...
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1answer
75 views

Converting DEM (TIFF) files to terrain files?

I want to create an app to show 3D using ol-cesium. In ol-cesium example it use cesium terrains, But I want to do it with my DEM files. How can I convert my DEM (TIFF) files to terrain files?
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1answer
37 views

Switching Mars DEM elevation values from negative to positive?

I'm using a DEM of Mars I got from UA's HiRISE website, and I want to convert it into an STL for 3D printing using the DEMto3D plugin. However, the raster values are all negative, so I thought I ...
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0answers
47 views

Extracting slope of aspect information using QGIS?

In What is SOA (slope of aspect)? @Spacedman explained to me what SOA means. Now I need help to understand how I could work with it and extract the data that I want. I want to use Qgis (with Grass ...
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1answer
48 views

What is SOA (slope of aspect)?

I’m reading an article that the authors talk about extracting values of SOA (slope of aspect). I can’t find anything related to that on Google. This article reference is : ZHOU, Yi et al. Automatic ...
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1answer
56 views

Seeking CSMapMaker (QGIS Plugin) equivalent for ArcGIS Desktop?

I'm looking for a tool or script or set of operations to mimic the output from a certain QGIS plugin called CSMapMaker, wherein curvature, slope, and a gaussian filtered DEM are overlain one another ...
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2answers
91 views

Using Ground Control Points in Agisoft Photoscan?

I'm fairly new to the Agisoft Photoscan program, but I am trying to build several models using aerial imagery and highly accurate GCPs, with coordinates collected in the field. I align my photos and ...
1
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1answer
87 views

Raster Volume Returning Wrong Volume

I have a clipped surface using Washington State Plane North (feet) added to a QGIS project using the same CRS. I am trying to calculate the area under this surface (a dirt pile) using SAGA Raster ...
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1answer
80 views

DEM not showing when loaded

I'm very new to QGIS, but in the past days I've created 3 different maps. I have now downloaded DEM data in ASC format, and when I open it as a raster file in a new QGIS project there is no problem, I ...
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0answers
12 views

When asked to select raster for elevation (in 3D configuration/QGIS) will be the DEM raster as downloaded or DEM raster re projected?

Do you need to re-project Aster GDEM data from USGS Explorer into a metric coordinate system in order to be able to view a map in 3d mode in QGIS? Or you just use the file input as it is downloaded ...
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0answers
18 views

Wrong value classification DTM ArcGIS

This DTM has mainly values between 0.7 and -0.7 (see histogram). In QGis it is displayed propper. In ArcGIS (10.5), although the histogram is okay, it displays values in the range between 8 and -8.
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1answer
37 views

Open TIN DEM File format

Anyone know a TIN DEM file format commonly used? In the context of a TIN DEM generator project, I am searching for a file format to save the TIN generated.
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3answers
73 views

Problem with CRS metadata for UK Environment Agency LiDAR DSM tiles?

I have downloaded some LIDAR DSM composite tiles from https://environment.data.gov.uk/DefraDataDownload/?Mode=survey and opened them in QGIS 3.6 with project CRS set to OSGB 1936 (EPSG:27700). ...
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1answer
119 views

Resample/Increase the resolution of Digital Elevation Model by QGIS [closed]

I have a DEM of 5m pixel. I wonder is it okay to convert it to 2m pixel? How to do that using QGIS? And what would happen to the original data, I mean the accuracy? Would it be reliable?
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1answer
14 views

CGIAR DEM converted to XYZ consists of Nodata only

I have a 30-by-30 tile from http://srtm.csi.cgiar.org/srtmdata/ Later I pre-process as outlined in the previous question CGIAR DEM + gdalwarp -- projection to Cartesian is not happening (see the ...
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1answer
17 views

CGIAR DEM + gdalwarp — projection to Cartesian is not happening

I have downloaded a 30-by-30 tile from http://srtm.csi.cgiar.org/srtmdata/ Then gdalinfo on the obtained single *.tif-file would yield Driver: GTiff/GeoTIFF Files: cut_n30e000.tif ...
1
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1answer
34 views

UTM Projection of DEM-data with gdalwarp

I have downloaded a certain tile from https://www.eorc.jaxa.jp/ALOS/en/aw3d30/data/index.htm, and after the requisite logistics (unzipping, putting all *.AVE_DSM.tif files into a single folder), I ...
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0answers
43 views

Howerive vector stream network from a DEM using D-Infinity Flow Direction algorithm?

I have been working with a 1m LiDAR derived DEM to create a vector stream network. Using the D8 flow direction, D8 flow accumulation, and a specified threshold, I was able to create a vector stream ...
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0answers
7 views

Getting 3D polygon to reach next isoline using ArcScene 10.5

I have a flood innundation polygon and the DEM used to generate it. I've added the Z coordinates for the innundation shapefile from the DEM, but I need to get it to reach the next isoline which ...
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0answers
48 views

Mars DEM: Interpretation

I have processed the *.tif-file from https://astrogeology.usgs.gov/search/map/Mars/GlobalSurveyor/MOLA/Mars_MGS_MOLA_DEM_mosaic_global_463m as gdalbuildvrt mars.vrt <filename>, and now gdalinfo ...
3
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1answer
87 views

GDAL: gdallocationinfo of CGIAR mosaic elevation data

I have downloaded tiles from http://srtm.csi.cgiar.org/srtmdata/ and unpacked the *.zip files into a directory. Then I ran, as has been suggested here: CGIAR SRTM to xyz using GRASS GIS, with ...
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0answers
28 views

How to open G.L.O.B.E. DEM files from NOAA

I need to open a free GLOBE DEM. I have downloaded some tiles from: https://www.ngdc.noaa.gov/mgg/topo/gltiles.html, but I don't know which software should I use in order to open those files. Is ...
0
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1answer
23 views

How to open a .dem file properly?

I have this DEM file downloaded from the internet. It's a text-formatted file and it looks like this: 1440 720 30 -9999 450 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -9999 -...
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1answer
90 views

QGIS 3.4 Stream delineation problem, lines running too far into ocean

I am using QGIS 3.4.4 Madeira version trying to delineate the stream and catchment areas of a small Bay in Honduras based on the technique of Hanz van der kwast tutorial "Stream and Catchment ...
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0answers
64 views

Extracting Ridges from DEM ALOS

I'm currently working on a forestry project for my thesis. It consists of the optimization of skids tracks planification using ALOS images. To this end I would like to extract obstacles such as steep ...
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1answer
35 views

Slope is not consistent with the elevation of DEM and seems to be incorrect

I have a DEM image which shows the elevation is from approx. 81 to 103. I expected the slope should be 0-22m. However, the result from DEM-Terrain Model-Slope is from 2.5 to 13.2. Anyone knows why?
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1answer
28 views

Adding height to dam in ArcGIS Desktop?

I'm having issues with flow direction in a reservoir heading in both directions. To try and correct this I think I need to add height to the portion of the DEM that currently represents the dam to ...
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0answers
28 views

Fixing sharp edges between GeoTIFF tiles? [duplicate]

I've downloaded a couple SRTM DEMS from http://srtm.csi.cgiar.org and when I load some of them into QGIS, there is a noticeable edge between 2 of the tiles (see image). Why does it happen? These are ...
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0answers
52 views

GdalDEM slope error in Jupyter

I try to calculate slope data. This is the DEM source https://www.earthenv.org/DEM Firstly, I translate data with gdal.Warp according to image UTM zone. Original image .bil extension so first I ...
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1answer
31 views

Applying same symbology to different DEMs?

I am using ArcScene and ran into this problem where I downloaded a couple of neighboring/bordering DEMs(in BIL format), imported them into the scene (as separate entities) and applied Base Heights so ...
6
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2answers
164 views

Raster antialiasing

I am looking for a way to antialias integer DEM data (hgt file) to float GeoTIFF. That way I want to avoid gdaldem hillshade artefact lines which you can see in this picture: I don't want to blur ...
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0answers
88 views

QGIS Exporting Layout as Blank PDF?

I am trying to export my map layout in QGIS3.4.5 on OSX 10.14. I've made the layout look exactly how I want it to look, but whenever I export to PDF, the PDF file is just a blank white page. The ...
2
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1answer
75 views

Mirrored Contours from DEM in QGIS

I am trying to create contours from a DEM in QGIS 3.4. I used the GDAL raster extraction contour tool. The contours are drawn correctly, but they are mirrored along the north line of the DEM (see ...
1
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1answer
77 views

Find higher elevation (10m) perpendicular point from stream network at regular interval

I have a stream network and for that network, I want to find the points at regular intervals which lie at 10m distance perpendicular from the stream.The final goal is to find the buffer of that 10m ...
2
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1answer
62 views

sampling error using gdalwarp on a subsetted VRT?

I am currently trying to prepare an SRTM subset including height conversion from EGM96 to WGS84 using gdalwarp. I encountered some strange shifts in part of the image. Here is a reproducible example: ...
2
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0answers
153 views

Increasing zoom level in 3D View QGIS Desktop?

I would like to increase the zoom level for my mosaic raster image in the 3D View of QGIS Desktop 3.4.4. I made a mosaic out of four raster images downloaded through the STRM-plugin for DEM data. ...
1
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0answers
22 views

How do I compare multiple years worth of geomorph changes in a river while drawing one profile line?

I have many years worth of DEMs of a river I'm studying. I'm very, very new to ArcGIS (think one intro class), and learned how to use the 3D analyst tool. What I'd like to be able to do, is to draw ...
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0answers
108 views

Easy way in PyQGIS to convert a distance from meters to coordinates?

I am attempting to clip DEM rasters (USGS, in WGS 84) into a set of tiles measuring 2.56km on a side, in QGIS, using python. So far, it appears that gdal_translate is working for me, using a ...
0
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1answer
43 views

How to generate DEM Generation in LPS

I have a Cartosat 2.5 m Imagery and Block files along with DSM Data. I wanted to generate DEM using Leica Photogrammetry Suite Software. Does anyone know the steps of generating same? I have to edit ...
2
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1answer
38 views

FME Surface Modeller “minimum number of points”

IN FME workbench 2016.1 I want to create a DEM from Multipatch-geometry contained in a geodatabase, for doing that I thought using the SurfaceModeller could work, where in SurfaceModeller I group the ...