Questions tagged [dem]

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

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34 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
166 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 ...
4
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1answer
389 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 ...
8
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0answers
291 views

Computing the horizon profile given a DEM in Python [closed]

Can anybody orient me towards an open source Python script that computes the 360° horizon profile (azi + elevation of highest topography in eye sight) from a single point (x,y,z) on Earth (account for ...
1
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0answers
83 views

Ensuring that a path goes downhill

GIS student hoping for a bit of wisdom on the Path Distance tool. I am doing a ski slope analysis, trying to find runs using cost grids (that incorporate slope, aspect, avalanche risk, etc.) While I ...
0
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0answers
30 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
72 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
215 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: &...
0
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1answer
29 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 ...
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 ...
1
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2answers
45 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 ...
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0answers
50 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 = ...
0
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1answer
86 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 ...
0
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2answers
9k views

Removing negative values from DEM using ArcGIS for Desktop?

i'm using (ArcGIS 10.1) and i want to remove a negative values from DTM in order to keep just a ground topographic surface.
2
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2answers
117 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 ...
2
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2answers
280 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 ...
0
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0answers
74 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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0answers
65 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
126 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? ...
1
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0answers
53 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
494 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....
3
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4answers
7k views

Mosaic to New Raster tool fail

I'm trying to merge 24 DEM files, after applying the tool (Mosaic to New Raster) only 11 out of the 24 merged. All the original files are in the same projection, pixel type, band, etc. I also ...
0
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1answer
53 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 ...
0
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1answer
22 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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0answers
42 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 ...
9
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2answers
9k views

Cropping Geotiff with gdalwarp

I downloaded a geotiff from the recently published 25m-DEM of the European Union (see: http://courses.neteler.org/eu-dem-new-digital-surface-model-at-25m/). One tile has about 5GB so I would like to ...
8
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1answer
150 views

Coarse Woody Debris extraction

I created very high dense point cloud of some forest plots using terrestrial laser scanner. Then removed points above 1.3 meter to see the coarse woody debris (Fallen dead trees). Attached is the ...
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 ...
8
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1answer
3k views

How to extract DEM (Digital Elevation Model) from 3D model

How can I extract a Digital Elevation Model from a 3D model of a building, made with SketchUp, using Blender,qgis or any other software?
32
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8answers
6k views

Generating random but believable digital elevation model? [closed]

Is there a way to generate a DEM, programatically or otherwise, that will feed into ArcGIS Desktop for further spatial analysis? Perhaps this needs to be broken down into smaller incremental steps: ...
3
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4answers
7k views

How to clean up contours?

I have .dxf file with contour lines representing elevation. But this contours are too "ugly" and elevation model looks just bad. As you can see on image, contours are not continuous... Is there any ...
1
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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 ...
0
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0answers
26 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 ...
0
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1answer
213 views

ArcGIS Raster To Multipoint Mac/OSX alternative

Is there an alternative to the ArcGIS Raster To Multipoint tool for Macs? The VIP thinning method is particularly of use. A comparative point cloud thinning/simplification tool to this would just as ...
3
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1answer
391 views

TIN interpolation problem

I made a TIN interpolation of some height points but the resulting raster appears with some weird lines (like in the pic) What can i do to avoid this result? Here are the input parameters. Sorry ...
0
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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
vote
1answer
78 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
99 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?
1
vote
1answer
161 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 ...
0
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2answers
231 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 ...
1
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0answers
51 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 ...
0
votes
1answer
592 views

gdalbuildvrt error when mosaicking SRTM data with different NoData values?

I'm attempting to mosaic together 9 SRTM tiles downloaded from CGIAR to produce a DEM of Borneo. I'm using: gdalbuildvrt Borneo.vrt BorneoSRTM/*.tif where BorneoSRTM contains the 9 tif files to be ...
0
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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 ...
17
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4answers
6k views

Manually correcting raster DEM (OpenSource)?

Is it possible, to correct a raster DEM by changeing the raster-cell-values manually, like by "painting"? My DEM (ASTER) have one small error where the elevation is about 300m below the actual ...
0
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1answer
127 views

Changing slopes derived from DEM using ArcGIS Desktop? [closed]

I have a DEM for a region over which I want to simulate an ecological process. I would like to run several simulations for the same region but I want to alter the topography for the simulations. ...
0
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2answers
2k views

Seeking Elevation Data for Scotland? [closed]

I have been searching for quality elevation data for the entire Scotland but I have not succeeded yet. Do you know where to get the data in Raster or Vector formats? Accuracy is very important as ...
0
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1answer
1k views

Seeking free elevation data for Thailand/Bangkok?

I am in the process of writing my thesis on flood hazard preparedness and forecasting in South East Asia, specifically Thailand. My analysis requires a medium resolution (even better, high resolution) ...
2
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0answers
41 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. ...
6
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2answers
7k views

Merging Raster Datasets of Different Resolutions using ArcGIS Desktop? [closed]

I am using ArcGIS Desktop. I have two DEMs in .tif format and I am looking to merge the two. The main problem with merging these are that they are different resolutions (one is 10m and one is ~20m). ...

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