Questions tagged [dem]
For questions about Digital Elevation Models (DEM), Digital Terrain Models (DTM) and Digital Surface Models (DSM)
1,399
questions
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16 views
Tools for programmatically finding a large flat site using height map data
I want to find the best location for a large science experiment. It requires two long (multi-kilometer), flat "arms" about 20 m wide separated by an angle between 45 and 90 degrees. I want to use ...
-1
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0answers
14 views
Getting DEM for many small areas located all over world?
I need to calculate the average slope over an area for thousands of polygons with locations all over the globe. The polygon areas are small, less than 1 square kilometer. I have to use a consistent ...
2
votes
1answer
29 views
Cutting/ exporting multiple terrain profiles to CSV files with QGIS?
I am trying to cut multiple terrain profiles and export them to CSVs (individual or combined).
I have a shapefile of the profile lines, and a DEM to cut the profiles from.
I can do this manually ...
0
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1answer
14 views
Stack for creation local shaded elevation tiles
I wish to create a local osm tiles with elevation information. I wish to display elevation info like a contour lines and shaded places linked with contour line values. I know about this source/...
2
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1answer
29 views
Where to extract Esri ASCII Raster Files?
In my spare time I am working on interpolating algorithms for Digital Elevation Models in C++. I always obtained my elevation data set as the ESRI ASCII Raster format because it is super simple.
...
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22 views
Least cost path creating unwanted straight lines
I’m very much a beginner with GIS and I’m stuck creating a least cost path.
Basically, I’m trying to highlight which river valleys would most likely be flooded in the event of a volcanic eruption ...
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0answers
32 views
Error using rsaga.fill.sinks
I'm using RStudio to delineate a watershed, and have had some difficulties when using rsaga.fill.sinks. My code up to this point is as follows:
#set rsaga working directory and version number
myenv &...
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0answers
19 views
How to apply the xyz translation vector derived from IceSAT altimetry to an ArcticDEM strip?
Laser altimetry data from the NASA IceSAT spacecraft is used to compute x, y, and z offsets for ArcticDEM strip files. The values of these offsets are contained within the DEM metadata, but are not ...
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1answer
27 views
Transfering height information from DEM to line feature to use in profile with ArcGIS Pro?
I am using ArcGIS Pro 2.4.
I want to make a height profile of a line segment. The line has no height information, so I want to transfer height information to the line from a dem.
How can this be ...
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0answers
22 views
Applying low pass/median filter over DEM in GeoTIFF format using ArcGIS Desktop?
I want to apply a median/low pass filter (over a few hundred kilometers) over my DEM to reduce the noise. I tried ArcGIS focal statistics tool but no luck. I got a blank GeoTIFF file.
How can I do it ...
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0answers
11 views
Interactive tool for editing TIN data
I created TIN to generate DTM using Mass points from Lidar data and river data that I made from stereoplotting. TIN results show there are several locations where the river elevation floats. So I have ...
2
votes
1answer
29 views
Using data from 30-meter DEM map to fill into missing pixels in 8-meter DEM map
I have a DEM map of 8-meter resolution, where some groups of pixels are blank due to the clouds (I guess). Is there a way in ArcGIS or GRASS to fill into those null areas with data from 30-meter DEM ...
3
votes
1answer
38 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 ...
3
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0answers
44 views
Removing noise selectively from DEM using QGIS?
I am looking for a processing tool that can remove noise selectively from a DEM (Mostly SRTM). My current workflow includes "Fill sinks" and "r.neighbours". The problem is that the tool is blind to ...
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0answers
9 views
Getting elevation data of a location using ALOS data
I'm working on a program to determine the line of site that a particular point will have using the ALOS data set from JAXA. So far I've managed to download a data set, and am a confused on where to go ...
1
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1answer
39 views
Editing specific portions of DEM using ArcGIS Desktop?
I currently have a DEM for an east coast city. Unfortunately, the elevation of an area containing a Dam is not accurate. I have the correct elevations as reported by the city. How would I go about ...
0
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1answer
42 views
Digital Terrain Analysis - Roughness Index [closed]
Currently I am working on a project dealing with terrain analysis based on a DEM. I came across the term "roughness index" using slope values from that specific DEM. On YouTube I found a video, which ...
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2answers
46 views
Open DEM in Google Earth?
How can I upload my DEM to Google Earth?
Agisoft Photoscan allows exporting Google Map tiles in Export DEM option but I have no idea how to upload it to Google Earth.
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29 views
Using MERGE command in QGIS?
I am working on QGIS 3.4.9 with Mac OS Mojave 10.14.5
I have two DEM raster files and I would like to merge them. Unfortunately, an error occurs and I don't know what to do.
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0answers
30 views
Using Viewshed Analysis in ArcGIS Desktop to Find Points Where Entire Area is Covered?
I have a DEM of an entire state and I would like to do a viewshed analysis. But instead of me using existing points to determine the viewshed, I would like to find all points where the entire state ...
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0answers
21 views
Join DEM and GPS data point ArcMap
I have a problem using ArcGIS. I have generate a DEM raster with a 3D online software and exported it in ArcGIS. So I have a raster of my surface. After that, I have some GPS point (x,y,z) that we ...
0
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1answer
25 views
Getting started with ArcScene?
I have been using ArcGIS for some time and am playing around with arcscene for the first time. I am having trouble getting started. When I add a DEM to a blank project it renders as a uniform grey, ...
1
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2answers
56 views
Comparing several values within each cell of a DEM
I am working with a DEM and got a GPS line of my working area.
I converted the GPS line into single measurement points. Now I want to compare each of these GPS points with the corresponding elevation ...
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15 views
Inverse values in raster heightmap
I have just converted a point vector into a tif using Rasterize in QGIS. And values are currently:
How do I completely flip the values as it should be Min -98.95 and Max 2.3
I can't find much when ...
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0answers
19 views
MicroDEM changes the aspect ratio of DEM
I downloaded a DEM from Open Topography (SRTM) and opened it in MicroDEM which changed the aspect ratio. The original DEM was 2329 px * 1679 px but that in MicroDEM when it was saved on disk was 2329 ...
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1answer
59 views
Finding lowest elevation in multiple polygons using DEM? [closed]
I have a polygon layer with six polygons. I need to have the lowest elevation point in each polygon using a DEM. The following explanation https://support.esri.com/en/technical-article/000011761 (...
2
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0answers
24 views
A GeoTIFF heightmap from SRTM embeds vertical planes along lat/lon grids in its 3D representation
I've downloaded an SRTM GeoTIFF from Open Topography and converted it into the grayscale image before I imported it into Blender to improve the quality. It is apparent that vertical planes are cutting ...
0
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1answer
12 views
How to Converting stream definition threshold to extract drainage network to metric scale?
I extracted two drainage networks from a DEM of 30 meters resolution with two stream definition thresholds: 1000 pixels and 500 pixels.
Can you tell me what this thresholds represent in terms of ...
0
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1answer
47 views
QGIS - processing area and calculating volume of polygon with know elevation from a DEM
I got a DEM of a watershed and I need to create a dam at a fixed elevation (with a rectangular polygon corresponding at the top of the dam) and calculate it's area (including the slope (fixed value) ...
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2answers
36 views
Seeking Uruguay or South America DEM or DTM? [closed]
Is there any DEM (Digital Elevation Model) or DTM (Digital Terrain Model) for Uruguay or South America?
I am aware of the Renare for Uruguay.
1
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1answer
25 views
Performing DTM compression using ArcPy?
I have a set of 32-bit TIFF files of DTM data (50 sm) and I need to save them as 16-bit.
In order to save some space, I compressed them using LZW algorith and saved as 16 bit tiffs using Arcpy.
But ...
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0answers
17 views
Finding the local extrema contour line on a DEM
I need to trace the top of a small levee on the side of a riverbank, based on a DEM.
This line is similar to a contour line, except that it goes through the local maximum instead of a constant level....
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35 views
Creating DEM from contour pyQGIS? [duplicate]
How can I create Digital Elevation Model using python codes in QGIS software?
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2answers
40 views
Cannot read pixel value from DTM raster with QGIS
I am using this DTM:
http://ags.cuzk.cz/arcgis2/services/dmr4g/ImageServer/WMSServer?request=GetCapabilities&service=WMS
At ArcGIS I am able to ready pixel value of the raster but at QGIS it ...
3
votes
1answer
55 views
Generate a viewshed and merge it with another image using GRASS/GDAL command line? [closed]
I've found a tutorial showing exactly what I want to do (merge viewshed and hill shade or map) but unfortunately it is for QGIS users and I need it in pure command line instructions because I'm in a ...
2
votes
0answers
52 views
Generate an accurate DTM with photogrammetry?
I generated imagery from a low flying drone (40 M AGL) equipped with a mica sense RedEdge multi-spectral camera and have processed the imagery in PIX4D and now am attempting to do some analysis in ...
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31 views
How to remove bridges and dams from DEM
Is there anyway to alter elevation of DEM where there are bridges and dams for the flood routing of the River?
I have to calculate discharge of the River from ancient times so at that time there ...
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0answers
21 views
Flow Distance Not Calculating for Entire Raster
I am trying to calculate the height above the nearest stream for an area. The problem is, it only does so for a portion ( the colored area below) of my area of interest. In the pic below, the black ...
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0answers
21 views
Elevation Map from Slope and Aspect Rasters
I am trying to create an elevation map (e.g., recreate a DEM) from the following input data:
Slope Raster
Aspect Raster
ASCII file containing XYZ data points (Easting, Northing, and Elevation for ...
0
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1answer
35 views
Why is my DEM so bright for some tiles?
I downloaded an SRTM DEM GeoTIFF file from Earth Explorer. It looks fine when previewing it on Earth Explorer (see picture) but when added in ArcGIS Pro the DEM looks too bright in some of its tiles.
0
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1answer
36 views
Extrude building footprints using raster (DSM) values in ArcGIS Pro?
Is there a way to extrude a buildings footprint shapefile into 3D buildings using values from the area's DSM in ArcGIS Pro?
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2answers
52 views
Learning DEM resources? [closed]
I'm starting on a problem where I need to find the high point inside a polygon that exists inside the bounds of a DEM tile. I'm teaching myself GDAL and I'll be using Python to access the GDAL library....
1
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2answers
58 views
Creating contour file from DEM?
Using a 3-meter DEM, can I create an accurate 5 feet interval contour file?
Or is the minimum interval contour I can get is 10 feet (roughly 3 meters)?
3
votes
1answer
69 views
CHM (Canopy height model) = DSM (Digital surface model) - DTM (Digital terrain model)
I want to create a canopy height model (CHM) which has the height of objects (trees, building, etc.) from DSM and DTM. Below is the step by step procedures which I did so far.
I use open source s2p ...
1
vote
1answer
86 views
Creating 3D image from HGT files?
Is there any command line tool to create a 3D terrain from a DEM SRTM HGT file like this?
I mean, given a camera position, a HGT file and a satelite image.
EDIT 1
First try to adapt mdsumner's ...
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0answers
22 views
Editing DEM file
I'm currently working on a small town flood inundation mapping , the DEM file i am using for simulation contains a breakwater built after a recent flood event. My question is if it is possible to edit ...
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2answers
46 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 ...
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0answers
25 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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2answers
75 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
18 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.
