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

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0answers
16 views

ALOS 30 m DEM (AWD3D30) — subsampled from smaller cell size; how to 'reconstruct'?

The new global 30m cell size DEM recently made available by JAXA is subsampled from a 5m DEM. They subsample the 5m DEM using the median and the mean; both products (30m DEM downsampled using median;...
3
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1answer
157 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 ...
0
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0answers
3 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
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0answers
19 views

Creating DEM using ArcGIS 10.1? [on hold]

I am trying to create a DEM. Is it true that creating said DEM is done by using the 3D Analyst tool, then applying raster interpolation and then the "Topo to raster" tool? Is that it? Or do I have to ...
2
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0answers
21 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
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2answers
47 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
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2answers
35 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
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2answers
136 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 ...
1
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0answers
36 views

Iterate through multiple polygons to produce a table with elevations using a DEM

My question is similar to this: Iterate through multiple Raster files and compute statistics using Zonal Statistics However, what I want to do is use Model builder to use individual polygons to ...
3
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1answer
55 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
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0answers
27 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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0answers
18 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 ...
2
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1answer
865 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. ...
0
votes
1answer
40 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 ...
4
votes
2answers
273 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 ...
-3
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0answers
24 views

Converting a GeoTIFF file to a DEM so I can later bring it into SketchUp

I have a GeoTIFF file that I want to convert into a DEM so that I can bring it into SketchUp. SketchUp only allows files ending in .dem, so I need to convert it somehow. Is this possible, and if so, ...
3
votes
1answer
91 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
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1answer
29 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
116 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 ...
0
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0answers
14 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?
-1
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1answer
24 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 ...
0
votes
2answers
43 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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0answers
45 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?
7
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2answers
3k views

how do you identify ridges on an elevation raster?

I was wondering whether anyone might be able to tell me in layman's terms how to extract or differentiate between ridges and hilltops from 10m elevation data using ArcGIS 10.1?
1
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1answer
42 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 ...
0
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0answers
23 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)?
2
votes
1answer
191 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? ...
1
vote
1answer
24 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
33 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
votes
1answer
389 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 ...
12
votes
4answers
3k views

What software to use for making digital elevation models from UAV aerial imagery?

I have a an unmanned aerial vehicle (UAV, also called a drone) and would like to use it to create a digital elevation model and orthomosaic over a smaller area (10 km2). My platform will be able to ...
2
votes
1answer
39 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 ...
0
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0answers
24 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 ...
1
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0answers
30 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, ...
0
votes
1answer
25 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 (...
7
votes
3answers
9k views

How to generate a DEM from a contour Shapefile?

I want to create a DEM from depth contours (shapefile) in QGIS. I've been trying to work out how to do this based on this previous question, notably from this link from that page, however I'm stuck, ...
7
votes
4answers
11k views

Viewing .las format LIDAR data 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
vote
1answer
28 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 ...
1
vote
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 ...
12
votes
4answers
8k views

Using SRTM Global DEM for Slope calculation?

I have downloaded SRTM GDEM (~90 km resolution). I am using ArcGIS 10. I have tried to use spatial analyst to compute for slope. However, I can not compute for the slope. The output values has ...
2
votes
1answer
45 views

Georeferencing an oblique angle photograph in repeat-photograph studies

Backround: Aerial photography and remote sensing can be used to measure current land cover and recent land use change. However, these technologies are fairly recent and therefore time series are ...
1
vote
1answer
285 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 ...
4
votes
1answer
913 views

Where can DEM data for all of British Columbia be found?

Is there a website or server from which a DEM covering all of BC can be downloaded - preferably at 1:50K scale? GeoBase has tiles for 1:50K and 1:250K, but they do not provide it as a mosaic. It's ...
0
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0answers
17 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 ...
2
votes
2answers
70 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 ...
1
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0answers
14 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 ...
0
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0answers
33 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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0answers
146 views

3D Polyline by Slope on Surface

I wish to project (continue/extend/whatever) a polyline upslope following a specified gradient along a DEM surface. Is there any way of doing this?
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 ...