Questions tagged [dem]

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

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20 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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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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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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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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2answers
93 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 ...
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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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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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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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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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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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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 ...
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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 ...
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53 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
44 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 ...
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38 views

Whitebox GAT branch depression big raster

I'm trying to run the tool Brunch depression form Whitebox GAT but the process doesn't work probably because the DEM is oversize For generate that raster i converted the single quadrant in the ...
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34 views

Filling NoData around bridges in DEM

Is it possible to fill no data around bridges without pixels blurriness (see picture). I use Elevation Void fill function, also tried in qgis No data filling and Grassgis r.fillnulls. I know, that I ...
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41 views

Creating 3D Local Scene using pointcloud, DSM, and orthomosaic from Drone in ArcGIS Pro?

I am trying to create a local 3D scene in ArcGIS Pro and display data fro drone flights. I have the orthomosaic from the flight as a .tif, the Digital Surface Model as a .tif, and my pointcloud from ...
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19 views

Assessing mapping accuracy of a DEM with different resolutions

I am mapping conical shaped depressions on the seafloor and would like to know at what resolution of the DEM is my mapping accuracy affected by. For example if I have a DEM of 7 metres, what does the ...
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216 views

Clip tool in ArcGIS Pro not working?

I'm trying to clip "Terrain" raster I downloaded from the portal (https://www.arcgis.com/home/item.html?id=58a541efc59545e6b7137f961d7de883) in the shape of a polygon (a country's boundaries) by using ...
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60 views

QGIS Display Attributes as Z Value for Point Shapefile?

I would like to create a state map that displays a 3D bar chart for each of 20 colleges (mapped as points) showing the percent share of engineering degrees earned by award level (i.e., assoc, ...
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72 views

Change detection using DEMs of difference and error quantification

Im currently working on a project in one of my seminars at university ("Advanced methods in natural hazard research"). We are modelling DEMs with Agisoft Photoscan using pictures from flume ...
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16 views

Calculate average slope values for a point using 50ft vector perpendicular to contour

I am trying to calculate the average percent slope of a hillside on either site of a data point. I tried extracting info from a DEM using a radius around the point, but I believe a more accurate ...
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28 views

Creating DEM in GRASS?

I need to create DSM and DEM with resolution 0.4 m. I tried to create DSM with resolution of 1m, everything was ok, but when I set higher resolution, then raster have a stripes with No Data values. ...
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33 views

How to retrieve GIS data in Multiple Orthophoto at point level

I have been using a python script that can read Data from Orthophoto(*.tiff) of size 300Mb-2Gb. But this is taking 32s per request of lat-long, which is not ok. I have different Orthophotos with ...
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35 views

How can I change the elevation of a lake on a DEM so I show the lake bottom contours?

I'm studying the drainage of a lake and I have a DEM of the lake and the surrounding area. I already identified the shorelines of ancient lake levels at higher elevations, but I would like to keep ...
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41 views

Erroneous contour polygons in QGIS 3

I have a global DEM and try to calculate contour polygons for 4 different heights in QGIS. In the first image below, you can see the colored DEM (white = lowest; yellow = higher; orange = highest) as ...
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42 views

Smoothing/denoising DEM to prep for 3D printing?

My DEM was generated from contour lines (as well as break lines and point height data), and the contours persist in the DEM despite doing some basic denoising (although i may not have used the optimal ...
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28 views

Interpretation of digital surface model (DSM) built from s2p tool and XML file

I am new to GIS. I am using s2p stereo pipeline to build Digital Surface Model (DSM.tif) from it. The height of certain point in this DSM.tif is 84 meters, and you can see from the color bar on ...
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1answer
74 views

EU DEM in GRS80 EVRS2000 with geoid EGG08 --> Make it comparable to Black Sea 1975 for Romania

I got contour lines for western Romania in vertical system Black Sea 1975 which is based on elevation data with 100 m resolution. Now I would like to compare that to the EU DEM with higher resolution. ...
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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?
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43 views

ImageMosaic plugin for DEM rasters on Geoserver

I'm using 30m DEM rasters from the NRCS Data Gateway. I use image mosaic to merge them. But when i preview i see black gaps between rasters. Coverager Parameters: How can i remove that black gaps?
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25 views

Reduce or heighten a DTM with overlaying polygons

I am using QGIS 3.01. I have a DTM over a historic area. There has been done archaeological surveys there, which suggest that the ground was several meteres below todays surface many hundred years ...
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162 views

Generate XYZ coordinates of DEM mesh/grid

Is there a way to generate a wire grid of plain text XYZ coordinates starting and ending points for each wire segment? I want to generate them from a digital elevation model. Preferably with gdal/qgis ...
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41 views

QGIS - Average a DEM into a single, flat plane

I have a XYZ point cloud that I am interpolating into a DEM. The data represents a surface that is relatively flat. I am hoping to be able to create a DEM of a single flat plane that best represents ...
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56 views

DEM provided contains high elevations (trees) that I wish to remove - is this possible

I wish to remove trees off my 3D aerial (high elevations). The files provided are .tif - unfortunately the trees are causing quite a bit of noise. Is there a way to set an elevation to remove them? ...
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69 views

QGIS DTM loading error

I have downloaded a full set of text DTM's for Northern Ireland from OSNI Open Data, but when I load them into QGIS, some of them do not appear. When I try to load the missing files, I get an error ...
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47 views

How to tilt a DEM?

I'm working on relictic fluvial terraces which have been tilted a few degrees during tectonic exhumation. I want to extract surfaces (terraces) with a certain slope angle and within a certain range of ...
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154 views

Getting errors after about 30 mins of processing Flow Direction using ArcGIS Desktop?

I'm trying to process the flow direction from a filled DEM using ArcGIS 10.2.2 and I get these errors after about 30 mins of processing, every time, no matter what I try. I tried changing the raster's ...
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666 views

Conversion of DEM raster to ASCII format in ArcGIS10.4

I have a DEM raster file in .tif format. I need to convert it to ASCII format. I used conversion tool in ArcGIS from raster to ASCII, but the result is in .txt instead of .asc. What should I do?
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34 views

Preparing two raster datasets for grouped barplot

I have two overlying raster datasets in ArcGIS which do have the same extent. One is a digital elevation model and the other one is a raster mask that contains three landuse classes (see figure below)....
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444 views

Converting elevation from EU-DEM (ETRS89) to WGS84

I'm having a hard time trying to use elevation data from EU-DEM. This data is in ETRS89 (EPSG:4258), according to their site. Now, when I extract the elevation for a shore, I get 0 meters of ...
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58 views

Patch DEM data gap with raster calculator

I have DEM data with some gaps that I want to patch with lower resolution DEM. Using raster calculator on ArcMap 10.5, I used this syntax: Con(IsNull("original.tif"),"lowres.tif","original.tif") But ...
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119 views

Manipulating / modifying terrain data to model a new surface

Short question: How to (intuitively) modify/manipulate a terrain with QGIS or alternative Open Source Software? The details: In order to build a habitat (ponds and depressions) for amphibians, a ...
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393 views

QGIS clipping DEM returns NaN

I was previously clipping a DEM (SRTM 30m) with one GeoJSON polygon and getting good results. With another GeoJSON polygon, I'm getting NaN values for the clipped raster. Any ideas on what is going on?...
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155 views

Merge DEM TIFF grids and get average value

I have two different DEM grids (basically single-band GeoTIFFs) and I want to merge them. The grids overlap and have different values, and I want to create a new DEM grid that takes the average or ...
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59 views

Implementing a DTM editing web service

I am planning out the creation of a web service for DTM editing. I can think of two ways of handling the DTM data on the backend, but are there better methods? Have a base dataset of DTM tiles. ...
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55 views

Adding raster created in GRASS (within QGIS) back into to GRASS (within QGIS)?

I am trying to use GRASS within QGIS - I have created a mapset etc in accordance with these instructions from other posts, and I am trying to create a raster map from shapefile contour information to ...
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271 views

ORFEO vs ERDAS: How to extract a good DSM with ORFEO

I'm trying to use ORFEO to check is it suitable to replace ERDAS to perform DSM extraction from stereo pairs. First thing, I can't use ORFEO for complete Pleiades images, it always crashes (my machine ...
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405 views

How to merge raster quadrangle tiles in qgis?

I've downloaded some dem tiles from here http://www.granit.unh.edu/data/search?dset=dem/dem174, which I'd like to merge into a single smooth digital elevation model usinq QGIS. So far I've tried ...
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193 views

gdal_merge.py aligns incorrectly at the seam of two GeoTiffs

I am trying to merge four GeoTiffs from the National Elevation Dataset (EPSG: 4269) into a 2x2 DEM using gdal_merge.py. For some reason, when it merges the upper two NED rasters, gdal produces a seam ...