Questions tagged [dem]

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

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43 views

Adding building/woodland elevation data to existing OS Terrain 5 DTM in ArcGIS Desktop [closed]

Would someone be able to give me the stepped process showing how to add building/woodland elevations to an existing DTM raster in ArcMap? I seek this in order to prepare a surface model for a ...
3
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1answer
131 views

Convert LiDAR GPX to DEM in QGIS?

I'm a water resources engineer with literally zero GIS experience. I'm working as a volunteer on a Engineers Without Borders project delivering safe drinking water to a remote community, where my team ...
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0answers
196 views

Slope calculation with GDAL

I compute a slope raster in percentage and then a slope raster in degree from the same DEM with a precision of 5 meters. Why my percent slope raster has a maximum value of 110% (+ 45 °) while my ...
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1answer
41 views

QGIS export DEM to SAGA grid - no coordinate system

I have created a DEM using survey points from a GNSS system. Works like a charm so far. I can extract elevation lines etc. However, when I export it as a SAGA grid it looses the coordinate system. I ...
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0answers
34 views

Creating seamless/uniform topography with multiple raster tiles?

I have multiple elevation raster tiles of an archaeological site and it would be extremely useful for me to visualize the topography as one 'uniform' image/layer. I have attempted to merge the rasters,...
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2answers
73 views

Finding date and time of Digital Elevation Model

I downloaded a DEM from the Copernicus site. I can provide the link: https://land.copernicus.eu/imagery-in-situ/eu-dem/eu-dem-v1-0-and-derived-products/eu-dem-v1.0?tab=download I would like to ...
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0answers
21 views

Problem with weird values in DTM and not showing correct elevation

I am still new to Gis and don't know if I understand what is wrong. I am working in a ocean survey program with point clouds. As seen on the picture the minimum depth is 1,92 and maximum 12,02. I ...
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0answers
38 views

Elevation distribution of protected areas using QGIS

I am using QGIS. Based on a DEM and a vector layer of polygons for protected areas in the Alps, I would like to calculate the areas of the respective protected area polygons in certain altitude ...
2
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1answer
206 views

Least Cost Path Analysis in QGIS?

For my Bachelor's thesis I try to reconstruct a road betweeen two ancient cities. One method I'd like to try is least cost path analysis with QGIS. I've worked with QGIS before, but mostly only ...
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0answers
31 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 ...
2
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1answer
74 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 ...
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2answers
237 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
31 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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0answers
52 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
46 views

Editing / grading a DEM raster? (Ex: detention pond and berm grading) [closed]

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
121 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
92 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 ...
2
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2answers
344 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
62 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
83 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 ...
-2
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1answer
40 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
134 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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0answers
58 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 ...
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2answers
559 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
76 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 ...
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1answer
24 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
55 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
46 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 ...
5
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0answers
46 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
66 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
27 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
34 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
83 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
35 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
108 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
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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 ...
1
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1answer
204 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
52 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
24 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
63 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 ...
2
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0answers
42 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. ...
1
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1answer
206 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 ...
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0answers
33 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
38 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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0answers
42 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 ...
1
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1answer
56 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 ...
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1answer
70 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
265 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
24 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
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1answer
53 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 ...

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