Questions tagged [dem]

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

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18 views

(QGIS) Add 3D geometry to a given point for 3D printing

I was wondering if it's possible to add 3D geometry to a given point. My goal is to 3D print a DEM model and highlight some points from a shapefile with a cilinder or something like that, so I can see ...
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1answer
144 views

Merging DEMs in QGIS?

Not the first problem I've had with DEMs in QGIS 3.4. Trying to merge 6 DEM tiles together into one. Process for this is simple: go to Raster --> Miscellaneous --> Merge. Once in the menu, select ...
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0answers
26 views

Raster artefacts after saving to GeoTIFF in QGIS

When processing DEMs created using downloaded SRTM data (initially HGT files) I produce a nice-looking product; however, saving this as a GeoTIFF creates square artefacts which are plain to see (and ...
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2answers
135 views

Mapping coastline geometry with SRTM raster?

Working on a map that includes a bathymetry layer, SRTM data for hillshade, and an accurate coastline boundary edge. I noticed though that the pixel resolution of SRTM 90m resolution creates visible ...
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0answers
21 views

Where can download a DEM for whole world in a single low resolution image?

I work in Blender to make Earth globe and I need elevation data for whole earth with low spatial resolution to make relief as a terrain.
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0answers
20 views

Generating TIN and/or DTM from point feature data

I have parameter data that is linked to points within a polygon area. I am trying to find ways of creating an interpolated layer for the extent of the polygon within which the points are located as ...
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1answer
173 views

Error creating DEM with Nearest Neighbour tool in QGIS?

I have an issue when I am creating a DEM with the tool natural neighbour on QGIS. When I extract my data directly on Qgis I have no issue creating a DEM. My points are coming from different sources ...
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17 views

Why is my DEM striped after using Mosaic to New Raster?

I have two DEMs that I need to merge together, so I used Mosaic to New Raster. The resulting DEM is striped...why is that? What does it mean?
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23 views

How to generate a DEM from a 3D point cloud in MATLAB?

I'm trying to generate a DEM (or a DSM if that works for this purpose) from a .ply point cloud in MATLAB so that I can generate a hillshade from it and this is what I have managed so far but have no ...
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63 views

Calculating volume of areas from CHM [duplicate]

I classified laying logs (tree trunks) from CHM (Canopy Height Model = Digital Surface Model (DSM) - Digital Terrain Model (DTM)) created from LiDAR point cloud. I converted classified logs into ...
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17 views

D8 flow routing in Google Earth Engine

I want to do some D8 flow routing on DEMs. Is it possible to do this in Google Earth Engine? My research so far indicates that it is not. For example, searching through this, I did not find any ...
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1answer
31 views

Creating raster with same size as DTM raster containing certain percentage of zeros and ones using QGIS

I've got a DTM and would like to add 1m to a percentage of the points, so I thought of creating a new raster containing either zeros or 1m and add the two raster together. I didn't find any tools that ...
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1answer
28 views

Automatic Vectorisation in ArcGIS

Is there any method or tool/model for ArcGIS to draw automatic line based upon raster data values. E.g i have a DEM and i want to automatically generate a line feature passing through all those pixels ...
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1answer
319 views

In qgis2threejs html output select deselect the layers not working

I used qgis2threejs to output 3d model with a dem and another viewshed output. I want to tick untick the layers for displaying and not displaying the layer.But the select unselect option in right ...
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2answers
4k views

Interpreting .ASC/LiDAR Data?

I'm a complete novice to the world of GIS. I'm involved with a project which requires LIDAR data to be imported into CAD software. When I go to the geostore, which contains LIDAR survey data ...
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1answer
150 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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2answers
420 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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34 views

Fill sinks and Strahler Order error in QGIS

I am working on a DEM of a watershed with a geotiff file size of 35GB. I am trying to execute watershed analysis tools and am experiencing errors in doing so. I attached a screen cast for Strahler ...
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1answer
67 views

Elevation change detection in GEE

I am trying to create a function in Google Earth Engine which would iterate through an ImageCollection consisting of DEMs and return a message saying when a big elevation difference occurs. I believe ...
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1answer
54 views

Understanding DEM of difference results in ArcGIS Pro [closed]

I am looking at channel change in a river in the UK and am using three DTM rasters to observe change over time. One of the methods I am using is to simply minus one DTM from another. I have got the ...
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1answer
78 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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1answer
70 views

How to extract contours from .jp2 DEM dataset?

This will be a little long-winded but I'm including all information I consider relevant. Problem: I have received a data set from a municipality that is a 3-layer LiDAR JP2 DEM and need to extract ...
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1answer
53 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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5answers
6k views

Manually correcting raster DEM (OpenSource)?

Is it possible, to correct a raster DEM by changeing the raster-cell-values manually, like by "painting"? My DEM (ASTER) have one small error where the elevation is about 300m below the actual ...
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1answer
122 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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0answers
28 views

QGIS 3.12 won't open new 3D Map View

I have a DEM that I'd like to render in 3D using QGIS 3.12. Various tutorials tell me to click on view>3D map view to do this. However, when I do this no window or anything pops up. If I go to View&...
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1answer
767 views

DEM files and r2stl()

In R The Volcano dataset has elevation values, but is not a DEM file. How can I convert my DEM files (from earthexplorer.usgs.gov) so that the I can access all the elevation values in a matrix (what ...
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2answers
630 views

Calculating relative share of an area of circle that has slope >15% in Germany

I need to calculate the share of buildable land for the 15 major german cities within a 50 kilometer radius of the city center. Part 1 of the definition buildable is that the area must have a slope &...
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4answers
46k views

Creating DEM from contours in QGIS?

I have a shapefile with contours and their heights. Is it possible to make a DEM from contours in QGIS without using GRASS? I found Creating DEM from contours using ArcGIS Desktop? but the answer ...
3
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2answers
297 views

Creating DEM Contour files from shapefile line data in QGIS

There are many question occurring on this forum regarding this issue, however the issue I am facing has not been answered in Generating DEM from contour Shapefile using QGIS?, which is that I have ...
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0answers
17 views

Removal of drainage channels (defined by steep slopes) from LiDAR DEMs

I have LiDAR DEM tiles (geoTIFF) that feature modern (19th century?) drainage channels but also remains of the pre-modern landscape. To perform further analysis of the latter, I want to remove the ...
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0answers
8 views

Using another imagery for reference of GCPs in PhotoMod software for DEM generation process?

As I am novice to the Photomod software, I can only find the option to import GCPs (.csv or txt) or TIN to generate DEM. If I want to use another already Ortho-rectified image as a reference, how can ...
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1answer
56 views

QGIS: Burning stream network (catchment area)

I need help from stackexchange because of a DEM correction problem... I have a DEM with a 5 meters resolution where one of the main river is cut by a large highway. In order to delete that topology ...
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0answers
39 views

How to add elevation data to tif to create DEM (SRTM satellite data)

I have a .tif created from the SRTM satellite data. The tif should already be DEM data as it was collected from the SRTM satellite. When I open the tif in ArcGIS, I don't see any height or z data, ...
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0answers
18 views

Selecting pixels from a raster by value

I have two digital elevation model rasters. I calculated the difference of these two rasters using raster calculator and got a single output raster. Now I want to highlight areas where the surface has ...
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1answer
21 views

QGIS Rastercalculator: unexpected results for cos() function

I've calculated the slope values of a DEM and created a raster with values from 0 to 51,3 (degree). I wanted to calculate the Cos of these pixel values with the Raster calculator (to calculate in the ...
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1answer
22 views

QGIS, clip my vector data with a DEM raster

I know that I cannot simply clip vector data with raster data. I'm working in QGIS and I have vector point data of earthquakes (XYZ), and I have it projected on top of my raster data (.tif). However, ...
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0answers
23 views

How to remove slope from DEM to better visualise topographic features of vriver systems in QGIS

0 I have a DEM of a river channel that i would like to remove the overall slope but retain features such as pools, riffles, bars etc. I have used the River Bathymetry Toolkit (detrending tool https://...
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1answer
64 views

Generating 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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0answers
19 views

Calculating TWI after getting the flow direction, flow accumulation and slope

There are many tutorials online with this, but it seems that people use different equations and/or what they put into the general ln(a/(tanb)) equation. Do I need to know the cell size of the raster ...
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0answers
42 views

Watershed delineation using hydrological Python library

We would like to delineate watershed polygon for a given pour point using hydrological Python library. Until now, we have tried these libraries: pyshed Grass (r.watershed) Whitetoolbox We have ...
1
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1answer
226 views

Detrending DEM in floodplain?

I am after the same solution to Removing elevation trend over sloped surfaces? I am following the steps outlined, but in the last step it states: In this expression [X'] refers to the the x-...
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0answers
37 views

Conversion of EGM96 to NAVD88

I am new to ArcGIS and geoids/ellipsoids, and I want to convert a dataset in EGM96 (the USGS SRTM DEMs) to NAVD88. I have the SRTM dataset from NASA downloaded and open in ArcGIS as .hgt files. I ...
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1answer
27 views

Looking for data to create contour lines at close range

This is my first post here and I'm new to GIS and I'm not massively even sure what I'm asking, so please be gentle! I'm attempting to learn QGIS through self-study and my idea is to take on a few ...
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0answers
12 views

Planchon & Darboux depression filling algorithm - Meaning of epsilon

I hope this is the correct place to ask this, but while trying to understand (and implement) the Planchon & Darboux depression filling algorithm, I came across a bit in the pseudo code I do not ...
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0answers
13 views

DEM from overlap monocular images Pleiades

I am trying to create a DEM from 4 overlap monocular satellite images of different dates from Pleiades using UP42.com. But I could find only information about stereo images processing. Is it even ...
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0answers
38 views

Removing rectangle line in DEM

enter image description hereI have downloaded Aster dem file. One of my dem file has rectangle line. Does any body know how to remove it? I am using QGIS 3.4.
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0answers
11 views

Combine depression filling and stream burning in one single step

As we know both depressions filling and stream burning will modify the DEM data. And I learned that sometimes we need fill-burn-fill to make the DEM is ideal for the follow-up steps. So can we merge ...
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1answer
13 views

Merging two DEM rasters in ArcMap

I tried to merge two DEM-rasters without any overlapping parts using "Mosaic To New Raster" tool. However the value range of output raster doesn't look correct. Assuming that (A1,B1) and (A2,B2) are ...
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1answer
26 views

Problem with open data ArcGisMapServer from SITG (Geneva) in QGIS

I would like to use this open data DSM data source QGIS from Geneva, Switzerland municipality. Here is the data server I tried to link it as an ArcGisMapServer source or as WMTS. But when I open the ...

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