Questions tagged [dem]
For questions about Digital Elevation Models (DEM), Digital Terrain Models (DTM) and Digital Surface Models (DSM)
1,430
questions
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6 views
Measure the direct sunlight throught LIDAR
First i want to introduce myself, i studied geography and i ended a masters degree in GIS and geomarketing. Now i'm a Java Developer and i'm trying to solve a problem related to the measuring of the ...
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0answers
9 views
Topographic Wetness Index difference between SAGA and TauDEM
I calculated Topographic Wetness Index (TWI) using SAGA and TauDEM. Overall trend is similar but SAGA returned larger values compared with TauDEM. Sometimes the deviations are as large as 7 or 8. I am ...
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2answers
35 views
DEM and vector data won't match using QGIS
I have just started using QGIS for my research at university. I have a DEM comprising Italian regions of Lazio, Tuscany and Umbria. I then have a set of vector data from surveys carried out in these ...
2
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2answers
53 views
Reduce noise in a raster (DEM) with R
I have several DEMs obtained from NASA-SRTM (https://www2.jpl.nasa.gov/srtm/).
I try reduce the noise infor these applying the function noise.filter ofwvtool package and receive the next message:
&...
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1answer
26 views
Order of input when calculating the difference between two DEMs over time?
I am attempting to analyze coastal landscape change. I have two DEMs from significant post-storm periods for my study area. I would like to produce a simple DEM of difference using the Minus tool. My ...
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11 views
Validation and verification of DEM products [on hold]
I am seeking a help for validating and verifying DEM products for determination of river topology. I want to identify the most accurate DEM comparing with already existing topological maps.
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0answers
23 views
DSM - DTM = -ve value
I want to calculate the elevation of a particular feature. I have both DSM and DTM as input data, both with the same cell size and same number of columns and rows (same resolution). For the DSM, min = ...
1
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2answers
29 views
Editing / grading a DEM raster? (Ex: detention pond and berm grading) [on hold]
I am looking for a way to adjust/edit the values in a DEM file, for example, to grade a detention pond and berm into existing LiDAR data. I have tried messing around with point shapefiles and the IDW ...
2
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2answers
29 views
Why does Blender not accept DT2 file (elevation data from EarthExplorer)?
Trying to do the Creating Shaded Relief in Blender tutorial
https://somethingaboutmaps.wordpress.com/2017/11/16/creating-shaded-relief-in-blender/
Got the file from SRTM 1 Arc-Second Global. Got ...
0
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1answer
34 views
Selecting coordinates of points below DEM (DTM)
I have a DEM file and a big list of X,Y,Z point (about 1M). Each of them can be below or above the DEM file.
Is there a quick way to select the x,y,z points below the DEM file using Python?
I did ...
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2answers
48 views
Problem processing Slovenian LiDAR DTM with GDAL (and QGIS): “too many stepY values” error
If I want to apply GDAL (version 2.2.3) on the LiDAR derived DTM (ASCII) from Slovenia (Link to Slovenian DTM below), I run into this error:
gdalinfo input.asc
ERROR 1: Ungridded dataset: At line ...
2
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2answers
46 views
Stream Feature generated from DEM is missing data
I tried to search other questions to see if this has been answered but couldn't find anything, so sorry if this is redundant. I use the Hydrology toolset in Spatial Analyst to create a stream feature ...
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0answers
28 views
Point/Area location of data in reference to geotransform of raster
I'm trying to understand how to interpret the position of pixel data within a GDAL raster, specifically as it applies to files containing height data. I'm create Triangular Regular Network (TRN) for ...
0
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1answer
17 views
ArcGIS 10.X - DEM raster creation - Point to Raster vs. Terrain to Raster tools [closed]
I have a bunch of LiDAR data that I need to make a raster DEM & DSM from. From what I can gather my options are use the Point to Raster tool directly on the Multipoint feature or make a terrain ...
2
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1answer
65 views
Can QGIS render and show DTM (Digital Terrain Model)?
I wonder if qgis can properly render a DTM (triangle) layer (as shown in image1) and become like a moveable (orbit-able) map to export to web browser?
If this is possible, where should I start from?
...
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15 views
Opening LIDAR DEM in QGIS with several .adf files
I have a LIDAR DEM dataset of a bay. What I got is a single folder with these files
I found out that the w001001.adf is the one that contains all the raster data and that the dblbnd, hdr, prj.sta ...
0
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2answers
48 views
Altitude extraction from a DEM(.tiff) file using Python [duplicate]
I have a DEM(.tiff) file and I need to know the altitude of certain points(coordinates).
I opened it like this:
import tifffile as tiff
import matplotlib.pyplot as plt
import rasterio
tfile = tiff....
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0answers
35 views
QGIS Grass 7 r.fill.dir
The following layers were not correctly generated.C:/Users/JIM/AppData/Local/Temp/processing_e2688a45d8934d16a2269a7ef6af8cbd/7eefcc8d13144f598fa7ab5bb5d657b8/output.tifYou can check the 'Log Messages ...
0
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1answer
19 views
SRTM DEM data appear mismatching in BW/Saturation or even brightness when gathered
I'm trying to make a DEM data of Algeria as I tried to download about 15 SRTM data but when added on ArcGIS and gathered they appear with diffrent saturation/brightness each, I tried then again to ...
0
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1answer
36 views
Comparing Slope among various DEM resolutions?
I'm comparing the slope products derived from DEMs of various spatial resolutions (1m, 10m, 30m) for a set area.
The trend I find is that as the resolution improves, the areal extent of various ...
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0answers
15 views
Interpolating Line in ArcGIS 3D Analyst
I am trying to make a 2D topographic profile using the Interpolate Line tool and a DEM. I've done this before on a different project; not sure why it's not working now. The 3D Analyst extension is ...
4
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0answers
24 views
Difference between merge and create virtual raster
I have the DEM of a defined region that has been split into sub-DEM with a resolution of 1 km x 1 km. When I merge the sub-DEM to create a single DEM (Raster -> Miscellaneous -> Merge), the overall ...
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0answers
55 views
Creating DEM from points in QGIS? [closed]
I'm trying to make DEM from points in QGIS.
I've read all the other questions regarding the same issue and tried them all. But, none of them worked.
For example, at the end of inverse distance ...
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0answers
18 views
Snap raster to specified coordinate point?
Is there any way to get a raster to snap to a specified coordinate point? The documentation for the snap raster environment setting says:
The lower left corner of the given extent is moved to the ...
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0answers
23 views
QGIS - Smooth merged DEM
I am having trouble making smooth contours from a DEM I created by merging two different DEMs of different resolutions (1m and 10m). The DEMs are partially overlapping and the contours I have ...
1
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1answer
31 views
Georeferencing a stack profile graph?
Is there a way to get a georeferenced profile graph from Stack Profile?
I have a DSM and use transects to get a profile graph from the DSM.
This gives an x,y value between 0 and 300m (the length of ...
2
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0answers
27 views
ArcMap - Blocky/Shattered Glass DEM Fix?
I am currently working with some data obtained from the Spanish Government to produce Digital Elevation Models for a site I am studying. I want to create a model that is essentially showing the ...
1
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1answer
49 views
Importing DEM to QGIS?
I downloaded a DEM file (package, rather?) of the entire US from usgs.gov. It's 30GB and contains quite a few files.
Is it possible to import this to QGIS to overlay the data on my map?
2
votes
1answer
61 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 ...
1
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1answer
51 views
Detrending DEM (QGIS)
I’m trying to detrend a DEM in QGIS.
The best guidance that I could find on the internet was this question : Removing elevation trend over sloped surfaces?
I couldn’t understand that so I would like ...
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0answers
49 views
Identifying upside and downside of road using QGIS?
I am a forest engineer and I have to reclassify a DTM in upside pixels and downside ones in relation to a line shapefile indicating skid trails network of the forest parcels.
I don't have necessarily ...
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0answers
19 views
Edit small details of DTM Raster in QGIS (flattening rocks or erasing buildings)
I got the following Raster, in which I would like to erase the rocks that appear on it.
I applied Gauss filter and got rid of small rocks (as noise), but which tool should I used to erase bigger ...
0
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1answer
41 views
Which layer for least cost analysis?
I'm new to least cost analysis. I have a DEM-layer of a region and I want to know what's the least cost path from a to b. Do I have to use the DEM layer to calculate that? I also have a hillshade ...
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0answers
26 views
Rescaling DEM for Blender
I'm working on getting some DEMs ready to bring into Blender to render hillshade. I've done this successfully before with low elevations, but on my current project mountaintops seem to get cut off.
...
2
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1answer
48 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
18 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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27 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 ...
0
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1answer
31 views
Applying 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 ...
0
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1answer
36 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 ...
0
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2answers
61 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
17 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
38 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
44 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
58 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 ...
0
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0answers
10 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 ...
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1answer
42 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
69 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 ...
-1
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2answers
93 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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0answers
32 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.
