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

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1answer
257 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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0answers
373 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
387 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 ...
2
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1answer
359 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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0answers
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. ...
2
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1answer
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 ...
1
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1answer
102 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
1k 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
134 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
466 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 ...
2
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1answer
66 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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0answers
131 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 ...
4
votes
1answer
203 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 ...
2
votes
1answer
171 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 ...
2
votes
1answer
357 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 ...
1
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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 ...
19
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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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0answers
426 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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0answers
433 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 ...
2
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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 ...
2
votes
2answers
448 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?
2
votes
1answer
142 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
votes
1answer
231 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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0answers
76 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 ...
0
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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 ...
2
votes
1answer
89 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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2answers
65 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 ...
2
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2answers
84 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?
3
votes
1answer
685 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 ...
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2answers
731 views

How to properly get the slope from an ASTER DEM in QGIS?

I have inserter a raster dem layer from ASTER satellite and I want to get a raster that has the slope of the area. I use terrain analysis > slope but the output is so wrong. Why is that? here is the ...
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1answer
43 views

Depressions in Texas DEM

I am working with the 10m DEMs and see some round depressions in Texas. I found this in two areas of about 12 sq km but do not have the tiles for the areas in between, so the area where I see this ...
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1answer
1k views

Removing negative values from DEM using ArcGIS for Desktop?

i'm using (ArcGIS 10.1) and i want to remove a negative values from DTM in order to keep just a ground topographic surface.
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1answer
2k views

Creating Digital Terrain Model from Digital Elevation Model using ArcGIS for Desktop? [closed]

I have a DEM and I want to create a DTM from that DEM. Is it possible to do this in ArcGIS?
1
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1answer
155 views

Where to download Mars DEMs and landcover?

I'm looking on the websites of the Mars Global Surveyor and the NASA sites, but all of the data is in jpeg or img form. Does anyone know where to find useful raster data sets for elevation and land ...
3
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0answers
166 views

Problem with Flow Direction in DEM

I have the following problem with Flow Direction Tool in my DEM and with such wrong calculated flow direction in the centre of DEM I am unable to delineate any watershed. What can I do?
0
votes
1answer
145 views

DEM files and r2stl()

In R The Volcano dataset has elevation values, but is not a DEM file. How can I convert my DEM files (from earthexplorer.usgs.gov) so that the I can access all the elevation values in a matrix (what ...
1
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1answer
55 views

raster topo map with gaps to DEM

I'm trying to create a DEM from this raster map: I managed to clean all the shapes and text. I tried to write a program which finds the curve pieces and connects them. But, I realized that it is ...
1
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1answer
79 views

Proof low deviations in DEM compared to point dataset

I am not sure how to achieve the following consistently: I have a regular distributed point dataset (surface elevations). From this I derived several DEM using QGIS IDW Interpolation method. Now I ...
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0answers
52 views

Managing or Reducing noise in a mosaic raster

I have created a raster with the Mosaic to New Raster tool from 3 separate rasters. However in my mosaic I have some consecutive pixels which seem to be the noise of the previous procedure. Is there ...
0
votes
1answer
110 views

DEM data processing

I downloaded ASTER GDEM Tiles and mosacked them in ENVI. After that I exported the Mosaic in tiff format and I opening it in Arcgis, the image is gray all through but the pixels are showing correctly. ...
1
vote
2answers
188 views

Where do I get Elevation Data for Scotland?

So I am new here and I arrived here because I have been searching for quality elevation data for the entire Scotland but I have not succeeded yet. Kindly help if you know where to get the data Raster ...
1
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0answers
39 views

How do I make a constant slope elevation model in arcMap? [duplicate]

I am currently working with ArcMap to develop an elevation model of a quarry showing how the terrain at the quarry site would look post-closure. One of the requirements is that the slopes placed along ...
2
votes
1answer
83 views

Unable to Produce Hillshade

I have been trying to create a hillshade using DEM data, however, regardless of the scale and z values I use the output is all black. I accessed the DEM data from a government source and clipped it ...
2
votes
2answers
220 views

Simulate sun movement

Are there any software packages/solutions that allow me to simulate the movement of sun or direction of sunlight over a period of time (e.g. 24 hours)? My purpose is to determine the regions cast in ...
2
votes
1answer
154 views

How to calculate point(or XY) for Start point of Slope and Endpoint of Slope along the Section line on DTM

How to calculate point(or XY) for Start point of Slope and Endpoint of Slope along the Section line on DTM. for instance
2
votes
1answer
43 views

How do I count the number of cells which can see each cell in QGIS

For each cell in a DEM I'd like to count the number of cells which can see it (i.e. direct line of sight) - Can anyone explain how to do this in QGIS? Thanks,
11
votes
2answers
458 views

Understanding min and max values with Mosaic to New Raster?

I have to combine several DEM rasters into one from this source: http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp, so I use Mosaic to New Raster tool. I set up the tool: I input the rasters (all ...
0
votes
2answers
903 views

Create DEM with 1 foot contours from lidar data with 1.4 meter resolution

I have Lidar data which contains multiple .las files for an entire quad. I have figured out which .las is the area I am looking for. I was told the data is in 1.4 meter resolution and would work to ...
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0answers
72 views

How to ignore certain values when creating profile graph in ArcGIS for Desktop?

I have a statewide DEM I am trying to create a profile of, however the DEM has some areas of widely varying size (bodies of water) where data was not collected and these areas were all filled by my ...
0
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0answers
41 views

automatic extraction of dtm using grass gis

i have generated dsm using erdas lps tool which is in img format. i want to import this file in grass gis and extract dtm. can you please tell me how to input the data , in which format it should be, ...