Questions tagged [dem]

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

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31 views

Spike and crater detection in DSM using machine learning / deep learning / computer vision techniques

I'd like to try machine learning / computer vision / deep learning approaches for detecting artifacts in Digital Surface Models, and am specifically interested in doing this for common artifacts like ...
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30 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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34 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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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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21 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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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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1answer
33 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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20 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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38 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
55 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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70 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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64 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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29 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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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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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
57 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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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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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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1answer
22 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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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
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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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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43 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 ...
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42 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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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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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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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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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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17 views

Altitude information for European highways

I need to calculate the gradient in major European highways. Fot this I need altitude data for each highway, let's say every 100 meters. Are there such kind of data publicly available? If not, I am ...
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41 views

QGIS create contour from DEM

I have created a DEM from points using the raster interpolation method, the TIN function, based on elevation of each point. However, when I try to create a contourline, the results show the contours ...
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1answer
55 views

Convert GOCAD .ts file to a raster for ArcMap Analysis

I have a multi-layered (10 layers) GOCAD .ts file of data that I would like to convert into a series of rasters. The documentation says it requires a program capable of reading GOCAD * .ts (...
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25 views

Calculating slope of numpy array using gdal.DEMProcessing

I am trying to compute the slope of a numpy array using gdal.DEMProcessing. Here is an example of what I am trying. Here in the example I am loading a portion of a DEM file, when I try to compute the ...
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43 views

ArcGIS pro Runtime Error: Cannot open shape file through Python Add-In

I am facing runtime error while running this Python script as an extension to ArcGIS Pro version 2.522081 I also checked for minor errors and typos in the script, have gone through the documentation ...
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1answer
21 views

Splitting GEOTiff of Mars

I am trying to make a map of a terraformed Mars in QGIS and as a part of that, I need to convert the Mars MOLA DEM into contour lines at an interval of 100m. However, the file is too big for QGIS to ...
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22 views

Flip Road-Lines based on the direction of apparently parallel DrainageLines derived using DEM

I have 2 FeatureClasses one is road lines (Red coloured as shown in the attached image) with random digitized direction and another is drainage lines (Blue Lines) derived using Raster DEM with correct ...
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40 views

Elevation obtained from USGS DEM is different from Lidar elevation

For a project I'm working on I need to calculate height of objects for which I know their spatial 2D coordinates (e.g. buildings). I'm using Lidar data to extract the highest Z value for an object, ...
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1answer
49 views

Getting elevation data from DEM

I'm trying to extract elevation data from a DEM file but I can't make it work. I want to extract contour lines from a given area, and label those lines with the proper elevation value. The problem I'...
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40 views

Get catchment area of a lake polygon in R

I have several DEMs as geotiff files which I load into R using raster::raster. Additionally, I have lake outlines (located within the DEMs) in the form of shapefiles which I load into R using raster::...
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12 views

ARCGIS-Slope map with different X and Y cell resolution

I have a tif DEM with different resolution in X and Y : cell size x =0.000222222222222222 cell size y=0.000111111111111111 with col=4501 and row =9001. The resulting slope map that I have is a tif ...
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1answer
37 views

Creating a DEM from PDF?

sorry if this is a simple question, but based on my search terms I keep getting PDF papers about DEMs. Someone has asked me to generate fill quantities off of their lidar data which they have ...
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1answer
22 views

How to get elevation value in CSV format in R from raster SRTM DEM file?

I am trying to get elevation value in meter using R programming. I have loaded raster library in rstudio: elevation <- getData("alt", country = "BD") How I can get those value with lat lon? ...
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10 views

Modifying existing DSM from new slope raster layer for optimizing solar panel in solar radiation tools

I would like to calculate solar radiation of some building roofs using area solar radiation tools in ArcGIS Pro. However, I need to modify my DSM (input raster) because I want to optimize the panel ...
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30 views

Adding two rasters results in negative infinity and positive infinity

I'm trying to create a hydro-flattened DEM according to USGS specifications. I have two rasters, a DEM of my study area and a raster that only contains the water bodies that I have flattened so the ...
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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
50 views

How can I 'fill in' the sea in a DTM raster in QGIS

I am using OS Terrain 50 data, mosaicked with R, to make some nice 3D maps using Rayshader. However, for coastal and island areas, there are large gaps where the sea is. How can I easily fill these in ...

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