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

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0answers
111 views

Difference in the elevations for the same building on two DSMs saved in *.asc and *.laz formats

The following question concern the same type of data as the one I've asked in Differences in the longitude and latitude between a LiDAR DSM and an optical image. Basically, I've downloaded a tile of ...
0
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0answers
35 views

Filtering Neighbor-pixel-values in DEM using ArcGIS for Desktop?

Working with ArcGIS 10.2.2. I have a DEM (GRID) in floating points. What I want to do is "clean" the grid by a 3x3 or 5x5 filter to identify and eliminate neighbors with the same value as the cell ...
0
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1answer
47 views

Free high resolution DEM or Lidar data for St Lucia

I found the 30m Aster DEM for St Lucia, but am wondering if there is some DEM or other elevation data source (Lidar) with a higher resolution. I googled, but have been unsuccessful in finding any free ...
2
votes
1answer
402 views

Polyline ZM: automatic vertex height errors correction

Paolo I've got many rivers (polylines ZM) with a lot of height errors in Polylines 'vertices. Vertices' Z errors are not all equal in height (i.e. they are not all at zero height). I must create a TIN ...
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0answers
6 views

Filling SRTM DEM 1 arcsec with 3 arcsec DEM in QGIS

I have a 1 arcsec (30 m) SRTM dem with some missing data. I want to fill the missing data with the values of the 3 arcsec SRTM dem (90 m), which is complete. How can I do this? Is that a good ...
0
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1answer
13 views

Selecting granule from ASTER Global DEM V2

I am following this tutorial in order to download ASTER Global DEM V2 data: http://www.echo.nasa.gov/reference/reverbastergdem_tutorial.htm on http://reverb.echo.nasa.gov/reverb/ Step 7 is to "Select ...
2
votes
2answers
4k views

Using Phantom 3 Pro to capture aerial imagery for small site plans and derive DEM? [closed]

I am curious if this consumer UAV can be used to capture imagery for further processing to stitch seamless imagery and to use as input into stereo/photogrametry software to create reasonably accurate ...
2
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1answer
963 views

How to fill holes/missing values in XYZ data / a DEM with QGIS?

I have equidistant XYZ point (text) data that I used to create a point grid. However, it's not perfect - there are some holes. I then created a DSM raster from it, which obviously has the holes too. ...
4
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2answers
277 views

Which method is better for display terrain in OpenLayers?

I want to display terrain in OpenLayers. So, I tried to use dem(.img) and convert it to dem(.jpg) on QGIS. But, the effect is very bad. My expected effect is (This picture is captured from google ...
7
votes
2answers
961 views

Normalizing point cloud data

How I can get Digital Height Model (only object heights, DSM - DTM = DHM)? Many applications can do this, but they convert it to GRID or TIN format. I was wondering if it was possible to keep the ...
32
votes
5answers
11k views

How to smooth a DEM?

I have a SRTM DEM and I want to create a shaded relief from it. I created the shaded relief in GRASS and the result is very nice, but a little rough becouse the area is near flat and the DEM is 90m in ...
0
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0answers
50 views

Finding depressions in LiDAR DTM? [duplicate]

I would like to find temporary moist areas based on terrain surface shape (depression) directly from an airborne LiDAR DTM. Could you help me to find some tools or algorithm to solve the task?
2
votes
2answers
210 views

Is there a way to clip a polygon layer according to DEM elevation?

I have a polygon layer on top of a DEM. Is there a way to clip the polygon layer according to elevation, ie the clipped result being only those areas of the polygon layer between x and y altitude? ...
6
votes
2answers
701 views

Choosing DEM in France?

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 ...
13
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4answers
4k views

Calculating elevation profile along line from a DEM?

Given a DEM (Digital Elevation Model) and a line (x1,y1) --> (x2,y2) (paired coordinates (x,y)), how can one calculate the elevation profile or cross-section projected on that line? I am looking for ...
10
votes
1answer
27k views

Calculating elevation profile for a polyline in ArcGIS 10?

My elevation data is a floating point tif. I have a road for which I need to calculate the elevation profile, but I can't see the tools to do this. Can I do this with ArcGIS, with spatial analyst/3D ...
1
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1answer
10k views

Opening TIFF DEMs in QGIS

I have files, in Tiff format, downloaded from ASTER-GDEM. Can I open this file with QGIS? If yes, how?
3
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0answers
32 views

Adding raster layer with RPC file in ArcGIS for Desktop for ortho rectification with DEM file?

I have a Pleiades image with its RPC file with .xml extension and a DEM file of the same area, but when I import them the orthorectification button is not active in display tab of property window. ...
21
votes
3answers
1k views

How to create transparent hillshade?

I get elegant transparent hillshades via a combination gdal and convert. Compare to grey-based hillshade commonly used, such transparent hillshades are very cool because they can be placed between the ...
0
votes
0answers
54 views

Iterating through multiple polygons to produce a table with elevations using DEM?

My question is similar to Iterate through multiple Raster files and compute statistics using Zonal Statistics However, what I want to do is use ModelBuilder to use individual polygons to define the ...
0
votes
1answer
12 views

Is there a way to represent just the “data” footprint in a tile index?

Is there an easy way to get just the "data" footprint for a raster. I have 3 DEMs and a tile layer. I'll be using the tile layer for referencing tiles of contours and ultimately I want to flag tiles ...
0
votes
1answer
10 views

How to project a large nonortho satelite image on a much smaller high res DEM?

I am currently attempting to orthorectify an image using GDAL. I have a very detailed DEM that I would like to rectify the image on top of. However, the DEM is smaller than the image itself; this is ...
0
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1answer
34 views

Inputing Temperatures

I am attempting to impute temperature based on elevation in ArcMap 10.2, using a regression equation. So far, I have been unsuccessful, as my output raster from my regression equation has the high too ...
0
votes
1answer
19 views

r.fill.dir blocked

I am trying to fille a DEM downloaded by Geobolivia http://geo.gob.bo/. The r.fill.dir module in QGIS/GRASS toolbox blocked few minutes after I launched it for the DEM. It is very strange as, for ...
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0answers
17 views

Identifying cliffs or clifflines?

I am looking for a way to accurately identify cliffs or clifflines. I have used the slope and reclassified for only high areas but wondering if anyone else has found a better way.
5
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2answers
3k views

How to create a catchment from a point using a DTM raster in QGIS?

I need to find a better way to delineate a catchment from a given point on a watercourse using a DTM - currently I am either using FEH, or if the catchment is too small using contours to draw manually....
1
vote
1answer
21 views

Getting DEM data programmatically with libgdal?

I'm writing a specialized tool in C to work with DEM data (typically GeoTIFF files, but one of the reasons I'm using libgdal is to leverage its ability to read multiple formats). I'm able to open a ...
1
vote
2answers
37 views

How to replace pixel values in a single band DEM?

I have a single band DEM as a GeoTiff. I would like to replace values above or below a certain threshold with 0. Can I do that with GDAL?
7
votes
4answers
11k views

Viewing LIDAR data (.las) in QGIS?

Is there an easy path to visualizing LIDAR data in QGIS? I have some USGS LIDAR data in .las format downloaded from http://lidar.cr.usgs.gov/. This means I have both the .las and metadata in .xml ...
1
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0answers
28 views

How to calculate Fractal dimension from DEM

I have a digital elevation model of a sea floor topography, and I have already creat TIN, shp, ras of this zone (only X, Y, Z(depth)) To calculate the topography complexity, I think fractal dimension ...
-2
votes
0answers
27 views

Creating Land cover map using Resourcesat LISS-III sansor image

I need to create a land cover map(LCLU) of a very small area(1.01171 sq km approx.). I am using IRS liss-III image as composite band image in argMap 10.3. Due to small area when i am clipping the ...
5
votes
1answer
205 views

Generating surfaces of different heights from LIDAR points

I am seeking a way to generate surfaces (polygons in a 3D space) of different heights from LIDAR point clouds, whose spacing is 4 points per square meter. The typical application is like roofs, which ...
0
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0answers
13 views

Referencing DEM tif to MSL using GDAL?

I have a single band DEM tif representing elevation. How can I reference it to a datum and convert it to MSL altitudes? I'm using GDAL command line tool but don't know where to start. I looked at ...
0
votes
1answer
22 views

how to create a grid - create a line of points - in ArcGIS 10.2

I would like to create a line of points spaced at 1km intervals along each of the four edges of my DEM, I was wondering whether there is a way to do this automatically in ArcGIS 10.2 and if so, how ...
0
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0answers
25 views

ArcGIS raster DEM Slope

I have a 3M DEM of Iowa and want to calculate slope percentage for the state, reclassify the slope percentages and then multiply those values by soil k-factor to get a proxy for soil erodibility. ...
1
vote
1answer
311 views

Merging USGS DEMs in ArcMap?

I've downloaded some USGS DEMs from the National Map, which appear to be .adf files. I can open them in ArcMap 10.2, but I need to merge them into a single mosaic. To do this, I've created a raster ...
1
vote
1answer
31 views

Drape multiple lines on a DEM with Postgis

I am trying to drape lines on a DEM by following this great tutorial: http://blog.mathieu-leplatre.info/drape-lines-on-a-dem-with-postgis.html When I do it on a single line by giving points ...
2
votes
1answer
2k views

Removing pixel values below 0 in Digital Elevation Model in ArcGIS for Desktop?

I made a DEM layer from a .las file (LiDAR). How can I remove the black area which contains negative values? Is it possible to set these values equal zero or null?
4
votes
1answer
172 views

Smoothing of a DEM

I have a DEM which has some individual pixels lower than those around them. This is a problem as I am using the DEM for pluvial flood modelling and therefore it is providing an incorrect ...
2
votes
0answers
34 views

Pixelated hillshade from 5m elevation data

I recently tried to create a hillshade of a valley in the Scottish Cairngorm mountains using some Digimap 5m elevation data (specifically the OS Terrain™ 5 DTM). The data was downloaded in .asc ...
1
vote
2answers
54 views

Select neighboring cells from a raster under conditions

I generated river networks (raster format) from a DEM and I also want to select the neighboring cells of the river networks from the original DEM, if the neighboring cells have a lower or equal ...
0
votes
2answers
42 views

Imitating symbology for DEM / Hillshading in ArcMap?

I am using ArcMap 10.2 and I am looking to copy the basemap styling from this map but I'm not sure how to go about doing that. I have a DEM of the area and the hillshading layer used but I'm not sure ...
3
votes
2answers
144 views

Calculate regional slope from DEM

I need to calculate regional slope for a coastline using a ~500 meter DEM covering a coastal plain and continental shelf where the slope for each grid cell is calculated by defining elevation extremes ...
3
votes
1answer
81 views

Resolving Sentinel-1 Interferogram Unwrapping error when constructing DEM/DSM?

I have been trying to create a DSM of a coast and some islands, and have run into some issues regarding how the data looks in the unwrapped interferogram (which affects my height data). I have been ...
1
vote
0answers
28 views

Merging DEM file generted many negative value in QGIS

With four DEM files downloaded by Python Elevation package, I merged them in QGIS 2.8.3. I use raster-> Miscellanaous -> Input direction, no more attribute was added. The four dem data has ...
0
votes
0answers
19 views

Auto fill fishnet labels attribute table?

We are working on creating a DEM on a certain area and we created a fishnet on a certain area with the labels ( dots ) now we have to fill the attribute table of these labels by the nearist contour ...
0
votes
1answer
51 views

How can I blend DEM rasters with GDAL?

I have several DEM rasters in different projections and at different resolutions. The rasters are not rectangular, but they have appropriate NoData values. They overlap enough that I should be able ...
3
votes
1answer
96 views

Whitebox GAT not starting under Windows 10 - General JAVA or Whitebox problem?

I am currently running the DEM preprocessing on a relatively large (50000 km2 at 30 m resolution) and steep DEM. The objective is to extract the stream network and some morphologic attributes (e.g., ...
1
vote
1answer
31 views

Rows and columns too high

I currently have a 5m DEM with 6000 rows and columns. I need to keep the spatial resolution but reduce the number of rows and columns to 1000. I have used the basin tool to separate the DEM and ...
3
votes
1answer
135 views

Extract river polygons from DEM

I would like to use DEM to extract a river network but I don't want to use the polylines. Is it possible for me to extract polygon (or raster) rivers from DEM? I'm using both ArcGIS 10 and R. If ...