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

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3
votes
0answers
100 views

Add a dam to DEM in ArcMap

I followed the instructions how to build a dam by whuber (How to build an artificial 'dam' across a river?) "draw a line segment" "compute the Euclidean distance to this line segment" ...
3
votes
1answer
65 views

Standardising DEM raster for a MCE

I'm trying to complete a Multi-Criteria Evaluation for an MSc assessment and am in the process of standardising my factor maps. Unfortunately, my DEM layer (ASCII file) keeps changing from this: ...
6
votes
2answers
646 views

best and most accurate free DEM?

I'm working in France. I thought the TanDEM-X was a free and open DEM but that does not seem to be the case. According to a few websites, the most famous free DEMs seem to be ASTER GDEM, SRTM, X-SAR ...
0
votes
0answers
25 views

Error : LayerRasterRead failed : Imagine Photogrammetry

I'm using Imagine Photogrammetry ( ERDAS ) and I would like to generate a Data Elevation Model DEM based on PLEIADES imagery. When I execute erdas , it seems like he is computing the DEM but after ...
3
votes
1answer
105 views

How to exclude water during contour generation?

I recently acquired a LiDAR data set that included a 1 meter DEM. I generated 1, 2 and 5m contour layers but I am seeing a lot of contours within water bodies. I suspect this is either caused by wave ...
1
vote
1answer
95 views

Making DEM from contours without elevation data?

I got a shapefile with contours, but no elevation data is present. We can assume as known info, that the contours mark elevations at known steps (say, 20 m). Is it still possible to restore the ...
1
vote
0answers
66 views

Why does the flow direction tool in ArcGIS desktop give wrong output (unique values from 1-255)?

I ran the flow direction in ArcGIS, and received unique values ranging from 1-255. I know that these values are wrong, and should be along the lines of 1, 2, 4, 8, 16, etc multiples. The DEM is ...
0
votes
0answers
30 views

Aster DEM damaged file (N30 E041)

I tried to merge several raster data sets ( from Aster GDEM), but one file is possibly damaged and I get a hole in my raster, see here https://www.dropbox.com/s/ypos9zhmsny476b/...
2
votes
1answer
130 views

How to find a point with highest elevation in area using ArcObjects

Is there a way to find a point with highest elevation in specified area by using ArcObjects? Let's say that I have a raster with DEM and I would like to establish some areas of interest in this raster....
1
vote
2answers
142 views

“ERROR 010214: Unable to read STA of…” while running Arc Hydro Geoprocessing Tools

Today I tried running the Combined Terrain with Unknown Sink and Stream Locations Tool from the Arc Hydro Toolset (version 10.3.0.58, ArcMap 10.3). As input I used a DTM with values between -10 and 19 ...
1
vote
2answers
158 views

Determining Min and Max elevation in Python using GDAL? [closed]

I have a DEM file and shape file of specific area ,and i want to Create a module in Python that writes name of each area which is shows in the picture, with the greatest differences in altitude on ...
2
votes
0answers
20 views

Applying colour ramp to DSM in ArcGIS using real elevation values as colour cut-offs?

I have a topo-bathymetric lidar DEM that I need to construct a CSR for in ArcGIS 10.3. I know how to make colour ramps and personalize them, but I'm wondering if it's possible to make a ramp based on ...
0
votes
1answer
32 views

DEM data to Excel using ArcMap?

I have downloaded a DEM from digmap and have opened it in ArcMap. I now want to transfer elevations from each gridsquare into excel to be used in a water routing model. Do you have any ideas how ...
0
votes
2answers
160 views

How to create a reservoir for a dam site?

I have created the watershed for a proposed dam site point using SRTM 90m DEM. Now my task is to create a reservoir or pondage where water would be collected from the watershed. Above a watershed can ...
1
vote
1answer
55 views

Regarding Atmospheric correction and Elevation DEM Projection system

I am trying to conduct atmospheric adjustment of Landsat 8 image bands using 6s algorithm (i. atcorr grass gis tool). It seems, in the input section, an elevation raster map should be provided. In my ...
1
vote
1answer
72 views

Creating contours from DEM for multiple files using ArcMap ModelBuilder?

How can i create an ArcMap model in ModelBuilder to iterate through a folder and applying contouring tool on all tif DEM files on that folder.
0
votes
1answer
43 views

gdaldem hillshade using command to calculate hillshade of whole folder [closed]

I need to calculate hillshade of folder using gdaldem hillshade which has 60 files in it. How can i do it using command prompt window.
0
votes
3answers
833 views

Why is my DEM in ArcScene flat, not 3D?

I am working with Digital Elevation Models in format TIFF 2km * 2km. As far as I know DEMs should have a 3d function but in my case the DEMs are flat. They only look 3d because of the hill shading. ...
2
votes
1answer
70 views

Looking for DTM for Morocco

I am looking for a DTM for the city of Agadir in Morocco. Could anyone help me to find it?
1
vote
1answer
89 views

Converting DTM data to STL?

I'm new here and was wondering if anyone could help? I'm looking to make some 3D maps using DTM data but need to convert it into .STL format for my MasterCAM to read so that I can generate the CAD ...
4
votes
3answers
158 views

Irregular XYZ point data to raster (TIF) - LASTools alternative?

I am trying to convert my irregular spaced point data (xyz) to a DEM and then, to a raster (geotiff). Because of the irregular spacing I need a triangulation first, right (so, no spaces are in the ...
0
votes
0answers
13 views

3ds city model to Digital Surface Model

I've got building and terrain models of a city in 3DS format. I'd like to transform these models to tiff images in order to create some kind of digital surface model (pixel value = height or altitude) ...
0
votes
0answers
27 views

DEM Mosaic Dataset Processing - Output Surface and Hillshade raster to same extent as input raster tiles

I have a lot of DEM rasters, tiled adjacent to each other. I would like to make a surface and a hillshade raster to the same extent as each DEM tile. Current issue: processing on a tile-by-tile basis ...
1
vote
0answers
55 views

Calculating flow distance of pixel from outlet using R?

I have created these raster files for a river basin: DEM Flow Direction Flow Accumulation Also, I have another raster with values of rainfall. All the 4 rasters have same spatial extent, ...
2
votes
3answers
281 views

Viewshed Analysis - use DSM or DTM?

I need to run a Viewshed analysis (ESRI 10.2 spatial analyst tool) to answer this: what areas will be able to see a proposed 30m high structure. I have the choice of a DSM or a DTM to use as the ...
1
vote
1answer
114 views

General guidelines for topographic contour to DEM conversion?

It seems that many different DEM resolutions (10m, 30m, 100m) could be created from a contour map (with, for instance 50m elevation changes marked), but of course some of the resulting DEMs will be ...
1
vote
0answers
84 views

How to orthorectify an image from a hilly region without sensor parameters but with DEM and some GCPs in ERDAS or ArcGIS?

I have a raw raster image from a sensor, but do not have the possibility to obtain the sensor parameters. However, I do have a (older) reference ortho image and a DEM with good accuracy. Both are ...
1
vote
1answer
104 views

Slope analysis of DEM in QGIS?

I have very strange problem with the raster analysis. I have a DEM as a Geo tiff and I do a slope analysis in QGIS. I've done this many times and everything was ok but this time I received reversed ...
0
votes
0answers
22 views

building artificial dam in a canyon [duplicate]

I want to calculate the water volume dammed by a dam in a canyon. I managed to calculate the water volume but I actually need a dam in a certain place of the gorge so I can pursuit my calculations. I ...
1
vote
1answer
62 views

increase resolution of generated hillshade on QGIS

I want to export a hillshade (geotiff) created from a DEM as an image for printing. But the resolution of the hillshade is way too low (900 colums, 1450 lines). Any way to upscale it? (I tried ...
1
vote
1answer
68 views

Bathymetric-topographic DEM color relief?

I am using QGIS 2.12 on a Macbook Pro running OS X 10.10.5. I have an interesting DEM for the California coast (which I downloaded from Santa Barbara, CA 1/3 arc-second MHW DEM. I've been playing ...
3
votes
1answer
47 views

Help with Rastercalculator - Filter areas with a certain height difference

I'm struggeling a little bit with the rastercalculator tool of QGIS. At the moment I am working with a DSM and a DTM. My aim is to filter all wind turbines out of the DSM and replace it with the ...
1
vote
3answers
360 views

Open LiDAR DEM of the UK with *.asc extension

I've downloaded a tile of a freely accessible LiDAR DEM of the UK from http://environment.data.gov.uk/ds/survey#/download. But I don't know how to open it. The files inside have the *.asc extension. ...
2
votes
1answer
37 views

applying a gradient to terrain curves in QGIS: problem

I'm trying to apply a gradient to terrain curves generated from a geotiff. I then choose a graduated style with a gradient color palette. everything seemed fine until I noticed that from a certain ...
0
votes
1answer
104 views

Reset a base elevation in Pix4D?

Does anyone know how to set a baseline elevation in Pix4D, or is that something that has to happen on the drone-capturing side? The reason is that I have an area which is flown with LiDAR, several ...
2
votes
0answers
76 views

Acquiring Digital Elevation Models for Argentina from commercial providers

I'm interested in obtaining Digital Elevation Models for areas in the 20,000 acre range, as I use them to create contour maps for agriculture. The USGS Earth Explorer has a wonderful free DEM ...
0
votes
1answer
85 views

ORFEO vs ERDAS: How to extract a good DSM with ORFEO

I'm trying to use ORFEO to check is it suitable to replace ERDAS to perform DSM extraction from stereo pairs. First thing, I can't use ORFEO for complete Pleiades images, it always crashes (my machine ...
1
vote
0answers
54 views

QGIS - .vrt DEM layer only partially goes to hillshade

I am using QGIS 2.12 on Macbook Pro running on Mac OS X Yosemite 10.10.5. I have six adjacent DEMs of the 7.5-minute quadrangle size (National Elevation Data or NED, I think). I loaded them into a ...
0
votes
0answers
32 views

QGIS problem with converting TIFF-DEM to ASCII

I converted a .tiff DSM into an .asc file. The output-file is stretched increasingly from th the upper to lower part (the dark structure under the classified DEM is the .asc-file). What went wrong? ...
1
vote
1answer
97 views

Elevation adjustment DSM using Ground control points

is there any possibility to improve the vertical accuracy of a given satelite DEM/DSM by using exact measured ground control points? And if so, which software is recommended?
3
votes
1answer
107 views

Calculate Volume over sloped ground in GRASS GIS

I am trying to do some volume calculations on a DEM with GRASS GIS. However, I believe r.volume measures everything from 0. The ground underneath the pile I'm measuring is sloped. I would ...
2
votes
0answers
38 views

Wanted: A rather large DEM

I am looking for a rather large DEM --- on the trillion cell scale --- to run some tests on. So far, I have found: 200 billion cells: The SRTM Global Dataset 30m DEM 120 billion cells: The National ...
0
votes
0answers
61 views

Generating DEM from point cloud and DEM differencing?

I have two point clouds obtained via structure from motion (ground photos of sand-dunes + Visual SfM/Agisoft Photoscan). If I wanted to generate a DEM from these point clouds and difference them to ...
0
votes
0answers
29 views

Minus elevation on DEM?

SRTM 30 m resolution data showing -23 elevation and SRTM 90 m resolution data showing -13 elevation at srikakulam dist East coastal side of India where as on google earth it is showing from 2 to 30m ...
2
votes
1answer
61 views

Clipping DEM / DTED data selecting by extent

similar to a few queries but really struggling to clip a DEM file from say USGS. Going to Raster > Extraction > Clipper and then "select the extent by drag on canvas", does not work. The process ...
2
votes
1answer
112 views

Combine digital elevation model (DEM) with point layer (QGIS)

I have two layers: The first one is a digital elevation model (DEM) as GeoTiff. The second is a point vector layer (start and end of street segments). What I want to do: Add elevation information ...
1
vote
0answers
61 views

What is the usefulness of the angle and direction of the sun parameters in hillshade? [closed]

These parameters refer to the angle as of elevation and direction of the sun hypothetically to the hillshade but why does that must have any importance?
3
votes
0answers
40 views

Blend overlapping DEMs using Open Source / Python

I'd like to blend edges of overlapping DEMs such that the join is a smooth transition (for use with InSAR). Apparently the best interpolation kernel for this, according to the literature, is thin ...
0
votes
2answers
113 views

Resampling DEM using gdal in python?

Using gdal I want to resample (in this case, oversample) a DEM. The only thing that should change is the pixel spacing, so I want to interpolate in between the values that I currently have. For this I ...