Digital Elevation Model (DEM), which could be a Digital Terrain Model (DTM) or a Digital Surface Model (DSM).

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2
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1answer
102 views

How to remove las2dem streaks from raster DEM?

I've created a series of DEM files using the las2dem tool from LAStools; however since I don't have a licensed version they have black streaks running across them. Does anyone know a good method for ...
0
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0answers
26 views

SRTM data to 7.5 min DEM or 1-deg DEM

I have an issue. I have SRTM data from here (http://www.webgis.com/srtm3.html) which is approximately 90 m / 3 arc-second. I want to convert it to 7.5' DEM or 1-deg DEM. Is it possible? Or is there ...
1
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0answers
17 views

Zonal smoothing on a specified area of a raster?

Is there any way to smooth a specify an area on a raster, such as a DEM, and smooth it? For example, I'd like to smooth out the artifact highlighted in the red box. What is the best course of ...
4
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3answers
122 views

What is the difference between DEM data sources?

I have started experimenting creating basic 3D elevation models in QGIS recently. It turned out for me that there are several free sources of DEMs, like USGS's EarthExplorer, CGIAR-CSI's Digital ...
1
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2answers
49 views

How to get the z values from a DEM?

I have to get to know the approximate amount of volume of rocks in one area. For that, I need the elevation information to see where slopes or inclinations are located. I downloaded from the USGS ...
1
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0answers
19 views

Ideal minimal area for watershed automatic delineation using DEM SRTM

I need to do a bunch of analysis on a city using for that, watersheds . As smaller the watersheds are, better are quality of my work. Due to the vertical accuracy of SRTM DEM, I know there are some ...
0
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0answers
39 views

Creating a Greyscale DEM from Multiband (RGB) GeoTIFF in QGIS

I'm trying to merge some river bathymetry with LiDAR from the surrounding riverbed using QGIS 2.14.0 Essen. The river bathymetric data is a GeoTIFF, and it comes with a separate scale associating the ...
3
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1answer
471 views

converting vectors to raster (burning streams)

I converted my stream vector to a raster file (using polyline to raster conversion tool). I anticipated that I would get a No Data row in the raster file attribute table, so that I could use a ...
1
vote
1answer
258 views

Creating DEM from cross sections in ArcMap?

I have a DEM in arcmap and cross section of a river which flows on the Dem in Hecras. I now the cross sections are more accurate. I want to make a DEM from some of my cross sections and stitch it on ...
12
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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 ...
1
vote
1answer
36 views

How to edit a DEM in ArcMap

I want to take a DEM and edit it using a tool in ArcMap where it will take all the areas above a certain elevation and lower them all to the elevation I choose. For example, I would want everything ...
2
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1answer
76 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., ...
2
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3answers
1k views

Advantage of Digital Elevation Model (DEM) in Agriculture?

I have given the task to create Digital Elevation Model (DEM)'s of an agricultural area. I am programmer with Computer Science background and very new to GIS can anyone explain what is advantage of ...
0
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1answer
25 views

Obtain free DEM data of South China

Is there any free source of Digital elevation model of China with the resolution of 30 meters or better and vertical accuracy of +-5m. Something along those lines
0
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1answer
42 views

How to calculate and compare RMSE between DEM using different interpolation methods?

I have data from aerial photo, it was built from stereo photo so I have 3D information that I am using for the DEM. I extracted it into shapefile. I want to get RMSE (Root Mean Square Error) from ...
2
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1answer
29 views
2
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1answer
873 views

Getting Negative Topographic Wetness Index (TWI) values in SAGA GIS?

I am getting negative topographic index wetness values in SAGA GIS - anyone else every get this? Not all negative values, but the minimum of the TWI range is negative for some steep watersheds we are ...
1
vote
3answers
290 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. ...
6
votes
3answers
4k views

How to create contour lines from point data using QGIS?

I'm using QGIS 2.4.0 and I have a shapefile of points with elevation data and X and Y coordinates. I'm using windows 7 OS. The idea is to create a contour line SHP using my point data. My question ...
0
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1answer
47 views

Removing every second row and column cells from a raster file

I have a SRTM 3 arc second topography model (.tif file). If I remove every second row and column of cells from the grid, can it be said that the model becomes a 6 arc second? Or does SRTM 3 arc ...
0
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1answer
296 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 ...
1
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0answers
60 views

DEM / Basemap Alignment

The image below shows the problem I'm facing. I'm trying to align a DEM with the ArcMap Imagery Basemap. Unfortunately, I can't make them to perfectly align. I tried changing the coordinate system to ...
1
vote
1answer
48 views

Creating DEM from point data in CSV files using QGIS?

how can we create a DEM in QGIS from point data in CSV files? A similar problem was discussed here, using a shp-file. Our CSV's are too big, so that dxf2shp crashes. So we are looking for another way ...
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0answers
26 views

Connect a photo and a DEM using landscape features

I'm helping with an image retake study in Alaska, we have historical (up to 100 years old) photos of the landscape (with lat/long) and we'll be retaking photos this year at the same locations. The ...
4
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1answer
2k views

How can I create a DEM from Point Data?

my boss gave me a small 3D-point-shape-file and asked me to make an DEM from it, wich I should put together with an older DEM of the same site, wich was made with Surfer. I created a raster-layer ...
0
votes
2answers
327 views

r.topidx error: required parameter output not set

I'm calling GRASS r.topidx from QGIS 2.2.0. I can get other tools to work on the DTM, for example r.watershed. But r.topidx I get the Oops message: Oooops! The following output layers could not be ...
3
votes
1answer
44 views

Change direction of polylines from DEM data

I am trying to define the direction of my polylines (which represent gutters in a drainage system). Does anyone know if it is possible to define the direction based on elevation data extracted from a ...
1
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3answers
96 views

Converting DEM text file to tiff file in QGIS?

I am trying to convert a digital elevation model in txt file format to a raster file (tiff) with qgis. The file format is *.dat. The coordinate system is Gauss Krüger, Bessel, 5. meridian. First I ...
2
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1answer
46 views

How to import a digital elevation model in Germany Gauss Krüger from .dat file?

i am very new to qgis. I want to create a hillshade file and also calculate the inclination. The structure of the digital elevation model data looks like this: 5390.0125 5659.9875 251.8 5390.0125 ...
2
votes
1answer
167 views

Filtering noise out from bare-earth DEM with terrace fields?

I have a 1m bare-earth DEM, derived from LiDAR data, representing a terraced landscape. For the sake of any subsequent use of the DEM (e.g., least-cost path, cost surface analysis, and the like) I am ...
1
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1answer
37 views

Convert dem and geotiff to collada model with texture

I have a digital elevation model (dem) file with corresponding orthophoto in geotiff format. What I need to do is to create a 3D model of the terrain with textures (preferably in collada file). I ...
1
vote
1answer
42 views

Free Digital Elevation (Terrain) Model of Europe or Germany

Is there any free (or not expensive) source of Digital elevation model of Europe or Germany with the resolution of 10 meters or better and vertical accuracy of +-5m or better?
0
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2answers
53 views

Filling only the deepest sinks/depressions in a DEM

I am trying to come up with a workflow that will extract the location of surface mines from a DEM. My original thought was to fill the depressions in the DEM and then subtract the original DEM from ...
5
votes
3answers
1k views

Determining bare earth from unclassified LAS file?

I have data in LAS format with RGB values created from Aerial photogrammetry using a UAV. I am trying to find a solution to extract the bare earth to create my DTM from the DSM. I have tried SAGA, ...
2
votes
0answers
31 views

Weird artefacts/pixels in QGIS-created shaded relief map

I'm working with 30m SRTM data on an terrain map of Cuba. I downloaded the necessary DEM files, merged them and went on to create the shaded relief map in QGIS 2.8 using Raster > Analyze > DEM ...
2
votes
1answer
54 views

Download of very detailed DEM files for Portugal?

Operating system: Windows 10, 64 bit. QGIS Version: 2.13.3 which I installed via the QGIS.org website. I need contour lines for a small area in Portugal. I saw a guide posted here: ...
9
votes
7answers
38k views

Extracting raster DEM elevations to vector attribute tables in ArcGIS Desktop?

I have an ArcMap 10 project with multiple layer groups. One layer is a raster DEM, another layer group is a bunch of vector shapefiles (including points, lines and polygons). The client wants all ...
0
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0answers
19 views

Elevation data from floating point DEM in ArcGIS for Desktop? [duplicate]

I have acquired a DEM from local municipality. It is a float point DEM, and the elevation of each pixel is represented as simply "pixel value". What would be the correct work flow to convert this to ...
3
votes
2answers
200 views

Creating DEM from las file without using Lastools

I want to create a ground model from a *.las file. The LAStools are available in QGIS but limited in use (generation of black diagonal in result file), so I can't use this. In the GRASS tools I can ...
3
votes
2answers
855 views

Canopy Height Model of LiDAR data in QGIS?

I am having a DTM and DSM files. I want to develop a Canopy Height Model in QGIS. Is it possible?
-2
votes
1answer
58 views

Expression into the raster calculator to invert DEM

I've made a DEM from first pass LiDAR data which I want to invert and run watershed segmentation and basin delineation over in order to hopefully extract tree canopy outlines and heights - I'm newish ...
1
vote
2answers
77 views

Trouble “extracting by mask” with a DEM layer and a shapefile?

I'm using ArcMap 10.2 and I'm currently trying to clip a county-wide DEM layer (.lyr file) down to a smaller area using a shapefile. The data frame coordinates system is set to US Feet which is what I ...
4
votes
1answer
48 views

The source of and possible solutions for DEM anomalies?

I am working with a DSM (Digital Surface Model) created using stereo-paired spot 6/7 satellite imagery. This DSM, and metrics derived from it will be used to create a Predictive Ecosystem Map (PEM). ...
1
vote
1answer
2k views

Fill sinks error in arcHydro

I am working on a project that is modeling runoff at a county level. The DEM used is lidar derived and has a 5 ft resolution. The general workflow I am flowing is Sink evaluation Sink Selection (to ...
12
votes
3answers
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 ...
1
vote
2answers
77 views

Filling up river corridors in a DEM

I'm currently working with a DEM (10 m x 10 m resolution) that has a lot of faulty elevation values in river corridors. In order to run a hydrodynamic model I'm trying to get the following done in an ...
23
votes
8answers
2k views

How to generate a random but believable digital elevation model?

Is there a way to generate a DEM, programatically or otherwise (arcpy or R?), that will feed into ArcGIS for further spatial analysis? Perhaps this needs to be broken down into smaller incremental ...
0
votes
2answers
374 views

How do I find the slope of road segments with point elevation data of the same linear path

I'm currently working on a project to calculate road grade along roughly 30 miles of highway. I need to isolate and portray all sections of road with more than a 5 percent grade; in hopes of finding ...
2
votes
1answer
96 views

Reclassifying a DEM using ArcMap 10.1

I have a DEM that am reclassifying into two classes. One areas less than or equal to 1000 and the other areas greater than 1000. Am accomplishing this using the reclassify Tool in ArcMap 10.1. The ...
2
votes
1answer
145 views

Finding Two locations with conditional search on DEM?

I want to find two locations H difference in elevation between two locations on a DEM. Ex: point A and B are my output after search on DEM. conditions are: buffer R distance around point A and ...