Questions tagged [dem]

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

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19 views

Add buildings contours to DGM for hydraulic analysis [duplicate]

I use Hydrology Terrain Analysis Tools in QGIS/ArcGis. Now I try to add some building contours to my DEM. I got building Data (Polygons) and a Raster DEM. Finally I want the buildings added to my DEM, ...
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1answer
114 views

How can I create GeoTIFFs from OS Terrain 50 data?

I'm playing around with R Rayshade, which creates lovely 3D terrain images using GeiTIFFs. I've been testing it out with SRTM 1 Arc-second images from USGS, but these are quite low resolution. OS ...
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24 views

Point to Raster - receiving integer although Points are floating point

I had to adjust a few raster cell values of a DEM, that's why I converted the raster DEM to point shape file and fixed that. Now that I want to generate my DEM again I have the following issue: While ...
3
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1answer
195 views

Interpolating DEM using Kriging in R

I have several DEMs as geotiff files which I load into R using raster::raster. Now some of these DEMs contain patches of missing values, represented by NA. I would like to interpolate these missing ...
1
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1answer
91 views

Flattening lakes for hydro-flattened DEM using polygon vertices in QGIS

I have the vertices around lake polygons that I want to flatten for a hydro-flattened DEM. I know that ArcGIS has a trend tool that will create a sloped 'plane of best fit' for a series of points, ...
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2answers
47 views

Guide book of SNAP

I would like to study SNAP Software made by ESA. I don't find any PDF or book online. Have you any ideas where I can find it?
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0answers
35 views

Reduce noise in QGIS hillshading [duplicate]

I'm using QGIS 3.12's Raster -> Analysis -> Hillshade tool on a fairly coarse DEM provided by the British Columbia provincial government. The DEM has elevation values between 500m and 2650m, so a ...
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1answer
46 views

QGIS loading DEM with unkown CRS

I am trying to load a DEM (img file + prj file) into QGIS 3.12.1 and use it as a layer over OSM. However I can't seem to get the CRS right, the OTF-conversion does not show the layer on the map. I am ...
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41 views

How to obtain shortest distances and elevation differences between points in QGIS

I have a river line shapefile and a grid of regular points. I need to know the distance between every point and the closest river line. Therefore I converted the line into points with the Generate ...
4
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1answer
102 views

Partially processing a catalog with an extent in lidR

I am using lidR to create a DEM of a very large area (over 1 million hectares). I have already processed a portion of this area. I would like to be able to read the entire LAScatalog so that the ...
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1answer
17 views

10m Resolution Seamless Dataset

I'm looking for a seamless 10m (1/3 arc second) dataset on a state by state basis. Is there a resource that houses this. I am trying to run a slope and aspect analysis for a variety of states but do ...
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1answer
51 views

ECW file solution doesn't work in QGIS in the latest ubuntu [closed]

In Ubuntu 18.4 I enrolled in a QGIS course in that course .dem file shows but .ecw can not show so what can be the solution can anybody tell me. QGIS version is 3.10.
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26 views

GDAL warp with a DEM as a reference?

I am using GDAL warp in Python like this (assume all variables not explicitly defined are defined somewhere else in the code): source_ds = gdal.GetDriverByName('GTiff').Create('results/...
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0answers
21 views

Identify local variation in a raster DEM

I want to identify local height variation in a high resolution DEM, so that the DEM is divided into 5 classes (1 being a sink and 5 being a peak). I then want to transfer this information to an ...
2
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1answer
140 views

Extracting individual trees from DSM in QGIS

I am trying to extract individual trees from a high resolution DSM in QGIS. I need to identify the trees and extract their individual height from the raster. Assuming I have identified the areas that ...
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0answers
26 views

NASADEM data around 180th meridian

I am following this thread What is NASADEM and when it will be released? and saw post from @markusN and start to download the data in nc format for few analysis in various countries. Recently I tried ...
2
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1answer
157 views

How do I get accurate DTM from DSM to get tree height?

I have drone imagery which was generated in Agisoft. From the imagery a DEM was generated and exported. I would like to know how do I get the Digital Terrain Model from this DEM? as I currently have ...
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0answers
49 views

Why is QGIS not recognising altitude from CSV file?

I used the Google Earth method for creating a KML file of points with latitude, longitude, and altitude as necessary information. After that I converted the KML file to GPX and then to CSV, through ...
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0answers
35 views

Resampling 13 arc second DEM to 1/3 arc second

I need to download DEMs for almost half of the U.S. but not all the locations have 1/3 arc second DEMs but the have 13 arc second. Can anyone help me how to resample 13 arc second DEM to 1/3 arc ...
3
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1answer
129 views

Apply volumes to points on a raster DEM in QGIS

I am trying to create a flood inundation map in QGIS from known flood volumes at specific points across a raster DEM. I could potentially do this manually for each individual point using contours ...
-1
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1answer
41 views

Mosaic 70 rasters to a new raster

Hi I have 80 rasters that I want to combine with Mosaic to new raster. 1- is the order of adding inputs important ? Is there any quicker way to add all those rasters ?]1]1
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0answers
16 views

Is it possible in ArcGIS to get cut -fill amount of a polygon feature class with Z-value without converting it to raster?

I have a polygon feature class with Z-value, representing a road alignment. I want to get its cut-fill amount using DEM. Is it possible in ArcGIS to get them directly (without converting feature class ...
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0answers
26 views

Generate multiple profile charts from multiple lines on multiple DEM [closed]

I'm trying to figure out how to generate automatically (need to be repeated 2k times) a profile cut of 2 DEMs, every 10 meters, with distance from start as a title and customizable colors/scales as an ...
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0answers
25 views

DEM from stereo IKONOS images in PCI Geomatica

I have 2 Panchromatic ERDAS IMAGINE file with RPC text files, metadata and .rrd and .aux file for each image. I'm trying to create a DEM from the stereo images. But by following the instructions of ...
3
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1answer
163 views

Extracting very small local ridges out of DEM

I have a DEM with small pits (one pit is approximately 5-10 cm wide, here shown as Hillshade). I want to extract the ridges of these pits to have polygons out of each pit (like this where I did it ...
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72 views

QGIS 3.12 raster reprojection giving no result

I would like to reproject my raster DEM from the EPSG:4376 (WGS-84) to the EPSG:27700 (British National Grid 1936). When I use the option: Raster -> Translate (COnvert format), as shown below: ...
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1answer
33 views

Calculate cost of predefined path

I am trying to calculate the cost of walking a predefined path. The path can be a line or a number of points along that line. I have a DEM and derived it's slope, which I will use as a friction map. I ...
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0answers
74 views

Why is my DEM layer turning black when I apply multidirectional hillshade effect?

I'm quite new to QGIS, and am experimenting with the hillshade effects. I've imported a DEM layer, and am simply trying to render it as a multidirectional hillshade. Every time I click the "...
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0answers
137 views

QGIS Hillshade not smooth enough

I have been trying for a couple of days to get hillshading to work as I need it to but have run out of things to try and have tried the solutions I have found through searching the web. I've created ...
1
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1answer
99 views

Getting elevation of surface in a specific point from DEM?

In my python code, I have to get elevation of surface in given coordinates. I know about Extract values to points tool in ArcMap, but I can't use that since it is very time consuming for me because I ...
2
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1answer
99 views

DEM interpolation, QGIS 3.10

A friend of mine gave me DEM resolutions of cells 5x5m, but there is something wrong with interpolation. When I try to make a cross-section of the terrain I get a pretty inaccurate cross-section, with ...
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0answers
46 views

Slope and hillshade layer not continuous in QGIS

I have been trying to create slope and Hillshade rasters from a DEM raster, which is in UTM11N. I tried different ratios (vertical to horizontal) but everything is in meters so it should work fine. I ...
3
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1answer
57 views

DEM elevations not appearing when rendered to single band pseudocolor

When rendering DEM file to single-band pseudocolor, the elevation values are not appearing. Attached are images of the proper template and my layer properties. Please let me know what other data would ...
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0answers
38 views

Watershed Delineation for Specified Streams

I have a set of streams (currently a shapefile (line)) which I need to delineate the watersheds for. I have attempted to use various QGIS tools, however, each tool I have tried is for delineation of ...
2
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1answer
157 views

QGIS 3x Viewshed plugin no result after re-projection

Continuing the query here: QGIS 3x viewshed plugin returns wrong results for visibility map I was trying to set proper CRS for my DEM on the area, where I am currently working on. Unfortunately, the ...
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0answers
29 views

Detrending DTMs

I've been using the method for detrending DTMs given here (in Clause 10.3): BAJR The results are encouraging but I'd like to 'flatten' the underlying terrain even more. One of my DTMs has ...
2
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1answer
219 views

Reading Elevation Data from a DSM file using Python

I am new to GIS processing and I have a DSM file with a .tif extension. I would like to read the elevation data from this file using python or QGIS. I can view this file on the delair web ...
3
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1answer
108 views

Changing elevation values of DEM

I am no expert in QGIS and I've already spend quite some time to find an answer to this, but I could not. Could anyone tell me how to change the elevation value of DEM? The one I have has been ...
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0answers
20 views

Create multiple rasters from one raster, based on Vector Input in R

I have a DEM for a big region. And I also have a vector-file for several sub-regions. I want to create as many DEM's as I have sub_regions. And I would like to do this in a for loop and for example ...
1
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1answer
47 views

Difference model between two raster (DEM) how to show values bigger than and smaller than 0,00

I got to DEM layers over the same area with positive and negative values in them. So I ran a raster calculator raster1-raster2. Now the raster got values with 0,000659 (This should be counted as 0,00,...
2
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0answers
118 views

Smooth contour lines/correctly extract contour lines from a DEM in QGIS

I have a DEM obtained as a result of the interpolation of elevation points TIN Interpolatin: I extracted the contour lines in QGIS and the result is this: After I tried to apply the Line Smoothing ...
1
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1answer
106 views

Extract cross-sections from a DEM

I have the centerline of a river and multiple lines perpendicular to it on Qgis. I would like to extract the cross-sections in correspondence to those lines, how could I do? I tried qprof but the .csv ...
1
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1answer
150 views

QGIS creating a DEM using OS Terrain 50 data - component tiles not matching

I'm attempting to create a DEM from OS Terrain 50 data (ASCII Grid data) in QGIS. The data is provided as multiple zipped folders representing sub divisions of OS grid squares. Each zipped folder ...
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0answers
62 views

DSM results from WebODM are not correct [closed]

I am new to WebODM and I am trying to generate DSM and Orthomosaic images using default settings in WebODM. The Orthomosaic image is correct by providing GCP but the DSM file is having inaccurate ...
3
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1answer
48 views

QGIS - Combining contours without elevation and point elevation data

I have a geopackage (Ordnance Survey Terrain 50) that has two layers: a layer with contours but no elevation data, and a layer of point elevation data. I'd like to create a DEM. The technique I've ...
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0answers
33 views

Programming an Interpolation for slope calculation

I'm working on a scientific programming project. I have a DEM and I'm supposed to calculate the slope all the long of trajectory. I had a problem with the interrpolation when I've plotted the graph ...
2
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0answers
75 views

Why does no line appear when using Interpolate Line in ArcMap?

I'm attempting to make an elevation profile from a DEM in ArcMap using the Interpolate Line tool. I've done this before, and it has worked great--basically I just draw a line with Interpolate Line, ...
0
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1answer
431 views

QGIS 3.10 problem with viewshed plugin

Continuing the strenuous trial of generating the viewshed for the points, from QGIS viewshed plugin returns error I am still getting an error: Traceback (most recent call last): File "C:/Users/...
-1
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1answer
211 views

QGIS Digital Elevation Model merging problem

I am encountering the problem with merging 2 raster digital elevation model layers (.tiff). The Qgis 3.10 returns an error as follows: The following layers were not correctly generated.C:/Users/...
1
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2answers
236 views

Calculating overall TRI value using QGIS

I have used the TRI (Terrain Ruggedness Index) function in QGIS>Raster>Analysis to develop TRI maps (see below). The maps are useful, but I am also trying to determine a single TRI value for the ...

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