Questions tagged [dem]

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

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50 views

Lunar DEM elevation data scaled by 2

I am working with a DEM of the lunar south pole in QGIS. I have currently set the projection to "no projection", or Cartesian co-ordinates (origin at the pole). The horizontal locations of features ...
0
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2answers
78 views

Classify DEM pixels

I have a differential surface model dataset. That was made: DSM subtracted from DTM, so for example trees have negative height. It is a raster (TIFF) dataset, Type=Float32. I want to create a ...
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0answers
26 views

No result with VRM tool ArcGIS

I am using ArcMap version 10.5. I downloaded the VRM tool from here: http://www.arcgis.com/home/item.html?id=9e4210b3ee7b413bbb1f98fb9c5b22d4. I followed the steps in 'read me; Unzip files (readme....
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1answer
41 views

Extracting DEM from PRISM data?

I have PRISM data which is in the following format. Are there any ways (software and methods) to extract the DEM or elevation information from these data files?
2
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0answers
135 views

Separate buildings from other objects from a normalized digital surface model [closed]

I have created a normalized Digital Surface Model using the substraction DSM-DEM. I have set a threshold value of 2 meters in order to eliminate objects such as shrubs, cars etc. My problem is how to ...
5
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1answer
1k views

Hillshade results look too grainy

I have a problem with hillshade function: I've set 315 azimuth, 45 vertical angle and 1 Z factor, but the result is very bad... The original dem file is a .geotiff from Global Data Explorer (Aster ...
0
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0answers
23 views

r.surf.area is underestimating area and giving negligible area

I am using r.surf.area in GRASS GIS to estimate surface area of a DEM. DEM is in EPSG4326 WGS84. It is giving a negligible area. Please give solution to this. Following is the output of r.surf.area.
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1answer
38 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.
1
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0answers
41 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 ...
1
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0answers
42 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 (...
9
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1answer
2k views

Ditch Extraction using LIDAR DTM (1m resolution)

I'm trying to extract ditches using the LIDAR DTM using the software eCognition but I am actually having a hard time since the paper where I based my workflow entitled "Ditches’ network extraction and ...
0
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2answers
1k views

Retrieving Elevation from Color in Raster DEM?

I'm fairly new to GIS work. I have a DEM in raster format, that is unfortunately not properly meta-referenced. In other words it has a legend where each color is assigned with the respective ...
1
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0answers
14 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
48 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 – ...
2
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2answers
86 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 ...
0
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0answers
21 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 ...
5
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1answer
201 views

QGIS: Edit elevation in DTM to get correct slope of a river

I am new to QGIS and just need it to do a hydrolocic analysis of an area of which I later make a flow model with HEC-RAS 2D. I made it according to this tutorial: https://www.youtube.com/watch?v=Ro-...
1
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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 ...
0
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1answer
19 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 ...
0
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0answers
28 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 ...
2
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2answers
172 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 ...
7
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1answer
3k views

Generating series of cross sections (profiles) along line using QGIS?

I have a set of points (xyz) along an axis. Is there any way in QGIS to generate cross profiles along this axis each 10 meters with, for example, +-15 meters right and left from the axis?
10
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1answer
2k views

What is NASADEM and when it will be released?

I heard some time ago about a new global DEM called NASADEM that was going to be released in 2017, and promised to be the best global DEM to date. What exactly is NASADEM and when will it be available?...
8
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5answers
1k views

Calculating total ascent along path? [closed]

I am working on a series of footpath routes and have been asked if it possible to calculate the total ascent that a walker would have climbed if the travelled along each route? I know that it is ...
0
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0answers
37 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/...
2
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3answers
265 views

Seeking open source bulk US DEM or imagery? [duplicate]

I am looking to create terrain hillshading for my maps that contain a small region of the US. I intend to show about eight to ten states at a time (at about ~1:5,000,000 scale). It has been some ...
0
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0answers
48 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 ...
1
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1answer
51 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 ...
1
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1answer
77 views

Volume estimation using multidate DEM

I have 10 multidate Cartosat-1 stereo pair derived raster DEMs of dates ranging over a decade over a river sand area. I want to derive volumes of sand deposited in that period within that area. Is it ...
1
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1answer
143 views

Mapserver / QGis and DEM GeoTIFF different nodata values behaviour

I Have a problem with novalue datas in my DEM… This is the workflow I did: my DEM datas are in multiple Arcgis ASCII grids… Each .asc files have a header containing "NODATA_value -99999.00". I ...
-1
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1answer
66 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 ...
1
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1answer
97 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 ...
15
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6answers
17k views

Burning stream network into DEM layer using ArcGIS Desktop?

I am working on a DEM that in an area where there is little relief. I would like to 'burn' the river network into the DEM so I can calculate flow accumulation and flow length accurately. I am ...
0
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1answer
93 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 ...
0
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0answers
13 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 ...
0
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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.
3
votes
2answers
600 views

How can I read Digital Elevation Model?

I downloaded a Digital Elevation Model of Mexico from here, and when I extracted the .rar, I got these files: Republica30_R60m.bil, Republica30_R60m.hdr, Republica30_R60m.prj and Republica30_R60m.stx. ...
0
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3answers
75 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). ...
1
vote
1answer
137 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?
0
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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 ...
1
vote
1answer
36 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 ...
0
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0answers
52 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 ...
0
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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 ...
3
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2answers
590 views

Bathymetric-topographic DEM color relief?

I am using QGIS 2.12 on a Macbook Pro running OS X 10.10.5. I have an interesting DEM for the California coast (which I downloaded from Santa Barbara, CA 1/3 arc-second MHW DEM. I've been playing ...
0
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0answers
49 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 ...
1
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0answers
23 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 ...
1
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0answers
94 views

Defining uphill side of roads using ArcGIS Desktop? [closed]

I have a big raster of a mountainous region, and I need to extract the uphill side of roads, from the road to the peaks of the mountains. For a road, I know the uphill side changes to become the ...
3
votes
1answer
91 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 ...
0
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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
votes
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 -...