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

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73 views

ArcGIS Raster To Multipoint Mac/OSX alternative

Is there an alternative to the ArcGIS Raster To Multipoint tool for Macs? The VIP thinning method is particularly of use. A comparative point cloud thinning/simplification tool to this would just as ...
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1answer
201 views

Getting aspect and reclassifying raster files using Python in a loop

By using Python in PythonWin 2.7.3, I tried to obtain aspect files of a list of raster files in a folder(called database_Dem20) and save it to another folder, database_Dem20/testOutput. In the same ...
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65 views

How to interpolate a Raster DTM

I have a GeoTIFF DTM produced from Agisoft Photoscan at 0.05 m resolution. However the interpolation used by the program to remove the riparian vegetation has used points from the channel, thus ...
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148 views

Is it better to take the elevation of a GPS unit or that of a Digital Elevation Model?

When searching of gps routes in wikiloc, for the trailrunning race "Transvulcania" I have several routes to look. I downloaded a lot, but every route has a distance between 71 kilometers and 74 ...
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2answers
395 views

Reversing Extract by Mask in ArcGIS for Desktop? [duplicate]

I have a DEM and I want to apply some tools to it (fill and others). In my DEM I've zones (drawn as mask) that need to be exlcluded from that processing. I don't want to apply the processing to the ...
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1answer
95 views

Merging USGS DEM files in ArcMap?

I'm trying to merge my DEM files into 2 separate files, one will have 4 files and the other will have 3. I've been reading every post from when someone asked this before for over an hour and I'm still ...
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85 views

QGIS - Edit Surface DEM to Add Buildings

Okay, let me start by saying I'm no expert in QGIS, I'm more into engineering. I'm building a 2D hydraulic model and I would like to add the building footprints (elevated) to my DEM, so flow will go ...
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166 views

What do negative DEM values mean?

My DEM elevation values varies from -255 to 81. What does the negative values imply? I have downloaded the dem from BHUVAN. About 90 % of values fall in negative category. How can I convert these ...
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35 views

Merging DEM files using PostGIS

I have several DEM files and I want to merge them to create a mosaic. I found the St_Union(raster) or St_MemUnion(raster) functions but I don't know how to use them. Are there any other solutions?
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110 views

From DEM to Topographic Wetness Index in SAGA GIS

I have DEM in GeoTIFF format and I wish to calculate Topographic Wetness Index in SAGA GIS. TWI tool in SAGA GIS expects that user provides two values - 'slope' and 'catchment area'. Since there's ...
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111 views

Obtaining sink morphometry from local minima points

I am working on LiDAR data from GIS and R and I want to extract landforms from the DEM. I have found a method to obtain local minima points of my LiDAR data. However, I would like to obtain the ...
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93 views

Understanding InSAR interferometry?

I understand that the result of InSAR interferometry yields a LoS deformation and if deformation in the vertical or horizontal is to be computed, it should require additional gps observations at the ...
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26 views

Export of a Raster Not Preserving Color [duplicate]

I'm trying to make a pretty shaded relief map using the technique described here. I've done this process several times in the past without any problems but today am perplexed about what is going on. ...
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1answer
111 views

SRTM DEM and satellite DEM fusion

I have a SRTM DEM and a DEM derived from satellite (Cartosat). Both the DEMs are registered perfectly. Now I want to carry out a DEM 'fusion' process to derive a higher quality output DEM. I am not ...
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2answers
223 views

Does a SRTM DEM image show details such as fields?

I'm working through the QGIS Training Manual where I have a step to get ... ... raster images (SRTM DEM) which cover the region you have selected for your course. SRTM DEM can be ...
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1answer
131 views

How to find the coordinates of the lowest point in a polygon

I am working in QGIS 2.6. I have a file of several polygons and I want for each one, to find the lowest point (where is it located and its elevation). I am using "Grid statistics for polygons" which ...
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2answers
3k views

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

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 ...
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72 views

Calclulate the shade from a DSM and from sun elevation and azimuth angle

I have a mosaic of about 5000 tiles of aerial orthophotgraphy taken at different dates and thus with different sun angles. Furthermore, I have a Digital Surface Model (1 m resolution). My goal is to ...
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1answer
728 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. ...
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130 views

Classifying DEM using Height Differences in ArcGIS ModelBuilder?

I would like to classify DEM into some classes, into a shp file with equal intervals of 200m (0-200m, 200-400m, 400-600m... 3400-3600m, higher than 3600m), by using Model Builder in ArcGIS 10.2. For ...
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1answer
237 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 ...
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155 views

World DEM vs ASTER Digital Elevation Models accuracy

I use DEM essentially to create surfaces on AutoCAD Civil 3D and then to create terrain profile views. I have been using mainly ASTER imagery from which I extract 2m contour lines in QGis and then ...
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372 views

Processing LAS dataset in QGIS 2.8.2 [duplicate]

I need to extract DEM from LIDAR dataset in QGIS 2.8.2. I have installed LAS tools in QGIS. I cannot configure my LAStools because I do not get Processing-->Options and Configuration and instead I get ...
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5answers
367 views

How to create 10m DEM from 30m DEM?

I am not regularly working in raster analysis. I have a 30M DEM and I would like to create a 10 DEM out of that. Is it possible to do this using QGIS? and How? EDIT: (I understand that a sub ...
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333 views

Relationship between contour interval and spatial resolution of a generated DEM

If I have contour lines with interval say 10, 5, or 2 (etc.), and I generated a DEM from them, what is the relationship between between the contour interval and the resolution of the DEM? Irrespective ...
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33 views

change from NAD 1983 to some PCS?

I want to ask how to change the coordinate system from NAD 1983 to some Projected coordinate system. I tried to change this DEM file to WGS 1984 (all of them) but when I did that my scale becomes 1:4. ...
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61 views

Extracting area from DEM Raster?

After applying constraints to the DEM I polygonised the raster (using GRASS r.to.vect.area) The result is shown below with a lot of vector with resolution = [30 * 30] Is there any solution to make ...
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101 views

Hillshade with too big pixels

I digitized some maps with isolines every 4m. I created a DEM and the Hillshade. But the hillshade has big pixels. I use ArcGIS 10.3. Is there something to be look out for that I might have done ...
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1answer
972 views

Can we create topographical map of private land using GPS elevation data?

Is there a way to create a relatively precise topographical map of a private land using GPS elevation data? As the land is a little bit over 100,000 square meters, the available regional topographical ...
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2answers
130 views

DEM with bathymetric contour lines in GRASS

I am trying to create a DEM from a bathymetric contour lines. Contours are in vector format and the elevation value is negative. To create the surface I have converted the contours in raster (v.to ...
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3answers
449 views

How to create composite hillshade?

The concept of composite hillshade is to combine multiple hillshades with different sunlight orientation to avoid blind spot. It requires to merge 3 hillshades images with 315⁰ (NW sunlight, default ...
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1answer
62 views

How to average gdal_hillshades?

For some unknow reason, my average of 3 hillshades is very dark : gdaldem hillshade input.tif hillshades_C.tmp.tif -s 111120 -z 5 -az 315 -alt 60 -compute_edges gdaldem hillshade input.tif ...
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123 views

Modifying DEM elevation data in QGIS using a polygon

I've tried searching through the existing questions but am struggling to find a succinct answer to what I am trying to achieve. For background, I am running a flood model in TUFLOW to help support a ...
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1answer
199 views

How to use SRTM Global DEM for Aspect calculation?

I need to derive a raster representing aspect for North America (from STRM data, originally in geographic lat/long). In most projections, true north is only map north along eg the central meridian so ...
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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 ...
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312 views

Creating DTM for two surfaces with point data and calculating volume between them using ArcGIS Desktop?

I have point data for a ground surface level which is captured in a grid of 35m spacings. I also have point data for the new surface level after soil has been removed which is captured at random ...
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1answer
25 views

Does Scimap work with QGIS?

Does anybody know if Scimap ( http://www.scimap.org.uk ) works with QGIS? I know it is supposed to operate with ArcGIS and SAGA but as I am very much a beginner with QGIS I would like to know if its ...
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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 ...
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369 views

Convert contour lines to DEM in ArcGIS [closed]

I've been trying without success to convert contour lines to DEM (Converting to spot heights is also a possible solution but I have not found a way for that either) using ArcGIS 10.2 (Advanced ...
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404 views

How to mosaic to new raster for multiple DEM tiles?

I took some DEM files and turned them into raster .tif files, i then tried to Mosaic them together using the mosaic to new raster tool and i keep getting two problems consistently, there seems to ...
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3answers
2k views

Ways to extract DEM for urban areas using Google Maps?

Is Google maps' elevation API suitable to obtain the high resolution elevation data for areas that have 3D building such as Manhattan? Would the API for example yield a significant different value on ...
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2answers
430 views

Classifying DEM according to elevation in R?

r<-raster("DEM.tif") How to do the classification based on every ten meters for example and have different colors too?
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1answer
124 views

Automatically adding Z-values from a DEM to an already created polygon

We have excavated a very large 5.000 year old fish fence, which was documented by photogrammetry, and is now being digitized. I started digitizing the orthophoto in QGIS and everything is cool. Now ...
2
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1answer
210 views

merge two DEMs of different resolutions? [duplicate]

I have two DEMs, the first one is in 30 meters of résolution and the second: 5 meters, and will like if there is a possibility of merging them to extend the area where I do my research?
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75 views

How to fit Google Earth satellite image to UK OS 50 DEM

I have extracted a DEM tile from the UK Ordnance Survey's free OS Terrain 50 dataset The tile contains spot heights for a grid comprising 51 nodes (West to East) by 51 nodes (North to South) with ...
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1answer
56 views

Intermediate files disappear in ArcGIS 10.1

I am working with ArcGIS 10.1 creating some slope and aspect files. I do this: DEM_park = ExtractByMask(mosaic_name, park_area) and it creates the DEM_park file in a default gdb with a default ...
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1answer
86 views

What exactly does hill shade or Shaded relief , if performed on SRTM DEM will output?

Two questions actually. Does shaded relief or hill shade outputs mean "expelling of shadows"? For a vast country like India, how to prepare a map from SRTM DEM, which does not have any shadow ...
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64 views

Why QGIS Raster clipper does not work on reprojected layers?

I try to clip a hillshade raster and I get this error. The hillshade was the result of a reprojected DEM from WGS84 to WGS84UTM. When I to clip the hillshade or even the reprojected DEM, I get the ...
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2answers
78 views

DTM posting and resolution

When speaking about a DMS or a DTM, what is posting? And what is the difference between posting and horizontal resolution?
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627 views

DEM Stream Burning

I would like to ask you guys how would i burn streams in DEM the following images will help understand what I would like to do. this is my DEM and the blue lines are my rivers. However, when I ...