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

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11 views

Draw the bounday through DEM

I want to calculate/draw the boundary extent in Glacier valley with the help of DEM. Can you please guide me which is the best tools in ArcGIS and steps to calculate.
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0answers
11 views

Intersection of a vector linestring and underlying DEM

Following is an screen-shot where ASTER DEM raster layer has been overlaid by a road linestring vector layer. I want to extract those DEM pixels which are lying exactly beneath the linestrings. I want ...
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17 views

Buffering/extrusion of a dem surface

I have a surface representing a DEM and i would like to add it some thickness. If i simply duplicate the surface and translate it down by my thickness, i get non uniform thickness, ie thinner where ...
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1answer
18 views

Reclassification of raster surface using ArcGIS for Desktop?

I have a raster surface with values ranging from 0 -100. I want to create a categorical classification (percentage categories of 5%, e.g. 0-5%, 6-10%...) and reclassify my surface into these ...
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0answers
15 views

3D distance and topography

I have a set of points and want to find out the nearest distance to a water body (poly lines) taking into account the terrain and get a surface distance calculation. I understand that the way is to ...
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1answer
27 views

QGIS vector layers do not match DEM?

I have a DEM (saved as a .tif) and, using QGIS, I want to clip the DEM using a vector mask. The function will not work. Am I missing critical step?
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2answers
101 views

Reducing elevation from DEM using ArcGIS for Desktop?

I am so curious how would I strip off elevation from the DEM. I don't know how I would explain it further but I have attached an image to clarify this. I wanted to eliminate the area shaded with ...
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0answers
18 views

Where is it possible to download a DEM for the Romanian east carpathians? [duplicate]

I'm quite new to GIS and have only done a few small tasks for Projects at University and the required data has always been provided. I am now struggling to find the specific DEM I need. Also other ...
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0answers
17 views

How to convert shapefiles into ascii grid .asc in QGIS?

I downloaded multiple zips that cover a small island from the Rhode Island Geographic Information System webpage, specifically the geographic files that make up Block Island. Here's the source: ...
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1answer
36 views

shapefile to gmt format

I have an ESRI shapefile of the contours of my study area, and I want to convert it into a format that is acceptable by GMT, so I can make an elevation map of my study area. Is that even possible? ...
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1answer
105 views

How to extract drainage line network from GRASS GIS and QGIS [closed]

Giving DEM as input is there any way to get drainage network? I am newbie to GRASS and QGIS ,provide any working examples in GRASS GIS and QGIS with procedure.
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1answer
19 views

DEM error when trying to do topographic correction in GRASS

I'm new to GRASS gis and I'm trying to do a topographic correction (i.topo.corr) of 9 ASTER bands using SRTM dem. I keep getting this error message: ERROR: Illumination model is of CELL type Is ...
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1answer
59 views

Stretched raster symbology not working in ArcGIS for Desktop?

I have some DEM rasters (from the same data source so I think they're uniform in all file specifications) that I'm symbolizing using the same stretched color ramp. I set the stretch type to min-max, ...
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2answers
38 views

Is there any way to 'clean' up ASTER v2 DEM data?

I downloaded all the tiles I needed, then plotted them to find that they don't all seem to have the same quality. Basically, you can see all the edges of a lot of the tiles. Is there any way to clean ...
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0answers
24 views

How to generate DEM from contours using QGIS? [duplicate]

Is it possible to generate digital elevation model using contour lines in QGIS 2.4 version?
3
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0answers
36 views

How to calculate an Illumination raster for fire ignition danger analysis?

I am doing a fire ignition danger analysis using this equation that I found in Millington (2012) http://www.jmecology.com/wp-content/uploads/2014/03/33-42-MILLINGTON.pdf IR = 4H + 3V + 2I – E Where: ...
2
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1answer
74 views

How to create contour lines from point data?

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 ...
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1answer
46 views

How to create a catchment from a point using a DTM raster in QGIS?

I need to find a better way to delineate a catchment from a given point on a watercourse using a DTM - currently I am either using FEH, or if the catchment is too small using contours to draw ...
6
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1answer
100 views

Ditch Extraction using LIDAR DTM (1m resolution)

I'm trying to extract ditches using the LIDAR DTM using the software eCognition but I am actually having a hard time since the paper where I based my workflow entitled "Ditches’ network extraction and ...
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15 views

Contour command in Spatial Ecology's GME

Has anyone been successful using the contour command from GME (Geospatial Modelling Environment)? I'm trying to create contours out of a DEM. I know you can do it in ArcGIS with 3D or Spatial Analyst ...
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3answers
32 views

Mosaic to New Raster tool fail

I'm trying to merge 24 DEM files, after applying the tool (Mosaic to New Raster) only 11 out of the 24 merged. All the original files are in the same projection, pixel type, band, etc. I also ...
8
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1answer
152 views

River boundary (bank) extraction from LiDAR

Is there any way to extract a river boundary (bank) from LiDAR data and its products (DEM, intensity image and slope) automatically? Digitizing is very time consuming.
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3answers
146 views

Normalizing point cloud data

How I can get Digital Height Model (only object heights, DSM - DTM = DHM)? Many applications can do this, but they convert it to GRID or TIN format. I was wondering if it was possible to keep the ...
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44 views

Simplified flood “model” / estimation from elevation data

The goal is to present an estimation of potential flooded area. But still keeping it simple. I know this will not be accurate. The question is: will it be good enough for at gestimate / rough ...
2
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1answer
21 views

Finding DEM/HIllshade sources California

Creating watershed maps for schools. I want to color ramp the elevation to show low and high points. What kind of files do I need and where to find them?
5
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1answer
95 views

Interactively determining upslope and downslope areas on DEM?

I know SAGA GIS can be used to interactively generate maps of upslope and downslope areas for a cell within a DEM, but the output is pretty ugly. An upslope area is defined as all cells (for a ...
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1answer
43 views

Extract elevation data from Landsat / MODIS imagery?

Just curious, have anyone tried to extract elevation data from LANDSAT or MODIS imagery? So far, I came across one journal by Toutin who did so using adjacent LANDSAT 7 imageries. Results seem pretty ...
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2answers
62 views

How can you create a depth raster from a DTM and a polygon in QGIS?

I have a DTM raster and a flood outline in polygon format - how do I create a depth raster for the flood outline (i.e. flood level minus DTM level)?
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1answer
47 views

Automatic Lineament Extraction from satellite images using ENVI? [closed]

Can you tell me the steps of automatic lineament extraction from satellite images? Can ENVI perform edge detection and the lineament extraction?
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0answers
35 views

Striping Artifact in Aster DEM Mosaic

I'm working with SRTM and ASTER data for a university project. My goal is to delineate watersheds and evaluation of these with ArcGis 10 and ArcHydro. But a striping error occurs with the flow ...
3
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1answer
37 views

Grid-like artifact visible in contour layers?

I am creating contours from an Aster DEM in ArcMap 10.1 I see a grid pattern appearing, particularly in areas of dense contours: I see the same artifact if I create a Hillshade layer so presumably ...
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0answers
34 views

How to extract elevation data from ASTER/SRTM? [duplicate]

I just want to know if there are any other tools available in QGIS apart from the Point Sampling tool to extract elevation data from ASTER/SRTM/CartoDEM (for India) data? When I convert these images ...
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0answers
9 views

Editing height of DEM raster using the adjacent cell values [duplicate]

I have a high elevation as 35m, but surrounding area height 6m/7m..I need to adjust that DEM (18m to 35 m) height using the adjacent area height. How could i edit the DEM raster? I hv been trying to ...
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2answers
31 views

TIN to Raster - specify raster's origin

How could I specify raster's origin, while using arcpy.TinRaster_3d?
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1answer
19 views

Is it possible to reveal the relief parameters “slope inclination” and “slope exposure” by dint of ASTER GDEM?

I’m trying to find information in technical and scientific articles – is it possible to reveal the relief parameters “slope inclination” and “slope exposure” by dint of ASTER GDEM? Or we can define ...
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0answers
14 views

Holes in Rasterized DEM from QGIS [duplicate]

I converted vector contours to a raster DEM using the rasterize command in QGIS. Generally the DEM looks correct, but the are a large number of holes in the DEM. The holes have a value of zero when ...
8
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2answers
110 views

What is a good metric for mapping accuracy

I have recently received a dataset that supposedly mapped the altitude a given region (a DEM). I would like to determine the accuracy of the new map by comparing it with a previously generated DEM. ...
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1answer
46 views

Rasterizing Contours - How to remove 0 values

I want to convert vector contours to a DEM. From other posts, I wanted to utilise the Grass r.surf.contours tool. Initially I converted the vector contour layer to a rasterized contours using the ...
2
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1answer
31 views

Algorithm behind custom tool of ArcGIS for Desktop called xyz2grid21?

I am a researcher from Romania and I have used xyz2grid21 ArcGIS tool (by Min-Lang Huang) in order to convert xyz files (LIDAR data) to ASCII and ESRI grid in order to obtain a DTM. I need to know ...
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2answers
41 views

Is SRTM 3 second arc free of non-terrain features?

I made an elevation map of my study area in Macapa, Brazil. But the region has the average elevation lesser than 30 m as I can see from my map derived from SRTM 3 second arc. According to my ...
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58 views

Creating one DEM from multiple ASC files

I am struggling with this several days and now its time to ask how to do it in QGIS. I have very detailed 27 ASC grid files with overall size of 9 GB created from 1m contours of large area (600 m2). ...
3
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1answer
68 views

How to extract DEM (Digital Elevation Model) from 3D model

How can I extract a Digital Elevation Model from a 3D model of a building, made with SketchUp, using Blender,qgis or any other software?
3
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2answers
79 views

How to manipulate lidar map using sun azimuth

Hi I am VERY new to QGIS and am struggling. I have a Lidar map and want to change the view so that the ground shadow is manipulated (looking for archaeological anomalies). I think it is the sun angle ...
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2answers
92 views

How to use OS Terrain 50 in QGIS

I am new to GIS and I wish to perform view shed analysis of wind turbines from a DEM. I have downloaded OS Terrain 50 and the data is contained within numerous zipped folders. I am using a Mac with ...
3
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1answer
139 views

Highest DEM pixel in polygon

I'm working with QGIS and have a big DEM raster layer with height information and a vector layer with many polygons, representing 1 x 1 degree tiles. Now I want to find for every polygon the highest ...
4
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1answer
212 views

Generate channel network (rainwater run off) - which algorithm is the best?

I want to compute DEM for a whole country (cca 79 000 sqr. km) and I need to be hydrologically correct as much is possible. After, for this correct DEM I need to compute drainage lines of surface ...
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0answers
72 views

Correlation between point feature (disease) and elevation

I have a problem! How can I calculate the correlation between point feature and Dem raster? Hypothesis: disease prevalence in high altitude is more than low altitude. I must do this in ArcGIS 10 and ...
2
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2answers
112 views

Filtering out canopies and buildings from DEM to have a bare earth elevation

Can anyone suggest methods in filtering out trees and buildings from a DEM so as to come up with a reliable DTM? What I have is a grid from a LIDAR data. I was going to clean out the unnecessary ...
2
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1answer
46 views

How to convert ASCII in x,y,z format using gdal_grid?

I have a map saved in (AFAIK) Arc/Info ASCII format and I would like to convert it with gdal grid but I am getting errors. My data (p.csv) is in the following format: 319053.25,319301.12,544.28 ...
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45 views

Developing a Slope Map of India [closed]

I am working on developing a Slope map of India (for my research), where I collected DEM from Bhuvan and tried to mosaic and then perform terrain analysis. But I am unable get the output since the ...