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

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36 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 ...
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1answer
48 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 ...
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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 ...
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1answer
14 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 ...
1
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0answers
116 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 ...
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1answer
11 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 ...
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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 ...
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1answer
20 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.
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0answers
33 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. ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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?
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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. ...
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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 ...
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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 ...
2
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0answers
35 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 ...
4
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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 ...
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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 ...
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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 ...
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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 ...
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55 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 ...
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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 ...
1
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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
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1answer
82 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 ...
3
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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 ...
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0answers
17 views

Zone map by interpolation of point data using d3js

Is it possible to generate a DEM (elevation model) or any zone map by interpolation of point data using d3js? Where can I find an example?
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0answers
50 views

False calculated slope?

After the DEM creation, I wanted to create slope layer. However the result has not satisfied me. I don't think the slope map is correct. Have you ever encountered false calculated terrain map?
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1answer
51 views

Determining height of raster class from DEM?

I have a raster layer with 2 already determined classes: Low vegetation and High vegetation. They don't mix, there is a characteristic border between them. It's a typical situation of altitudinal ...
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0answers
28 views

How to generate DTM from LiDAR point cloud data? [duplicate]

I have LiDAR point cloud data (X Y Z Intensity), and I want to generate DTM (only ground point). Is there any solution (algorithm or software)?
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2answers
47 views

Extracting mean elevation values from DEM based on multi-polygon shapefile?

I'm trying to get the overall average elevation for different areas delineated within a polygon. Originally, I converted the Digital Elevation Raster (DEM) to a polygon and tried to merge the ...
1
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1answer
27 views

How to find lowest elevation change using raster data and w.r.t muliple polygons

I am trying to complete a spatial analysis which yields areas (parcels of land) which are comprised of polygons (in an attribute table) that correspond to the lowest land slope regions or smallest ...
1
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0answers
37 views

Cannot store raster in custom database schema

I want to store an elevation raster in a postgis database. However a problem occurs. I use the following command: raster2pgsql -I -C -e -Y -F -s 4326 -t auto dem.tif schemaname.filename | psql -U ...
2
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1answer
40 views

Open data DEM containing drumlins

I am currently looking for a DEM containing some drumlins to perform some morphometry on it. It should be a free one, or at least to be downloaded free of charge. I have already tried to find a free ...
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0answers
26 views

DEM from Google Earth, Natural neighbour fails

Does anybody know, why using the tool Natural neighbour fails, when trying to get raster from shape? I followed the instructions here: https://www.youtube.com/watch?v=bLbY3iMBW-A, but all I get are ...
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1answer
28 views

How to generate DTM from point cloud data? [duplicate]

I have point cloud data obtained from drone. I need to generate DTM out of it. How can I generate and I checked options in ArcGIS and QGIS. I was not able to find any.Could anyone suggest a method to ...
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0answers
36 views

Negative values in r.watershed flow accumulation

I am trying to process a DTM by using r.watershed in QGIS 2.14.3, with the GRASS GIS toolbox. It should be the file named: "Number of cells that drain through each cell". I get some negative values, ...
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1answer
32 views

CHaMP Topo Processing Menu not active in ArcMap 10.1

After converting a .tiff file to TIN, I have now installed the CHaMP Topo Processing Add-In which should allow me to convert Topo TIN to DEM. However, after installation, the entire toolbar is grey ...
5
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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 ...
1
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1answer
49 views

Opening >10gb DEM files and clipping?

I have a 5m DEM for an entire province in Spain. It is over 48gb in size and is in asc file format. I only need a very small, 50 km² area. I open the DEM in ArcDesktop, and i get the loading bar ...
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0answers
18 views

EU DEM licensing compared to SRTM and others

Where can I find the actual full license of the EU DEM? That download webpage has a checkbox saying "I am aware that I am downloading non-validated data and I accept to not distribute the information ...
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0answers
16 views

Reproduce a raster with same cell size but different no of columns and rows

I have a DEM raster of 200m resolution, the no of columns and rows are 2458 and 2845, I want to reproduce this raster in a way that the cell size remains the same i.e. 200,200 but the no of columns ...
2
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2answers
80 views

Pixelated DSM using LAS Dataset to Raster?

I am using ArcGIS 10.2.2, and I am trying to create a DSM out of some LIDAR data. After checking the LAS Dataset properties, I see that I have an average point spacing of approx 0.3. I tried ...
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0answers
35 views

How to match 2 different rasters?

1st rasters: Satellite image that represents NDVI value [Cell size (5,5) OR resolution :5 meter. Number of rows and columns: 5000, 5000] 2nd rasters: DEM represents heights [cell size (9.0106388, 9....
1
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1answer
22 views

DEM ASCII for HEC-GeoRAS

I have a hard time understanding what ASCII files are. I have this DEM in asc. I try to import them into ArcMAP 10.3 and they appear in my naked eyes as images however what I found on internet is ...
0
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1answer
33 views

DEM to RGB-GeoTIFF (land-/waterarea colored separate)

I want to create a colored basemap out of a ETOPO dataset. Is there a way to color the land (masked by a landpolygon) and water area separate and combine them later. The result should be one GeoTIFF (...
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0answers
29 views

Flattening topography while retaining structures in QGIS?

I have a set of Terrain data in both DSM and DTM form. What I am trying to do is extract the features (buildings, hedges etc...) that have been removed from the DTM, but I don't want the topography. ...