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

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Raster Interpolation of Different DEMs in GRASS

I am trying to generate a DEM for surface runoff modeling in GRASS. I have a DEM for the entire watershed at 1ft resolution and another for the small area within that watershed (a parking lot) I am ...
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128 views

Strange gdaldem hillshade artifacts

I've downloaded 9 chunks of 1 arc-second NED in IMG format from the National Map. I'm trying to create a hillshade from them. I'm using: GDAL 1.10.0, released 2013/04/24 First, I combine them and ...
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2answers
717 views

How to extract elevation data from binary .ADF elevation format at given coordinates?

I have a high resolution digital elevation model available. The ground resolution is 1 meter and the file format is adf which is some binary ESRI grid raster format. I have a script the outputs x/y- ...
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2answers
812 views

Best Program to use for DEM data?

I need to estimate the elevation at various access points of some rivers in South Carolina. I use the elevation information to calculate the average gradient (feet/mile) between two access points. The ...
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1answer
111 views

How to integrate DEM in Kriging and other interpolation methods?

I would like to see the difference of including DEM in interpolation from without. Some studies on climate data interpolation suggest that interpolation performs better with DEM. How do I do this in ...
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0answers
81 views

Calculate surface elevation from DEM of pit and known volume with which it is being filled

I am using ArcGIS 10.1. I have a DEM of a pit. I have a known volume of material that I want to put in the pit. I want to know what the elevation of the flat surface of this material will be ...
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2answers
593 views

How to extract mountain peak points from a given digital elevation model?

For past couple of days, i m trying to determine how many mountain peaks are visible (line of sight) from a given location using POSTGIS. The data i have is DEM for Swiss and address locations from ...
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1answer
906 views

How can to merge DEMs in ArcGIS for Desktop 10.2?

I'm trying to merge some dems downloaded from USGS. When I used arcgis 9.2 there was an expression to be used in raster calculator to do that. I used it again but unfortunately it doesn't work in ...
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1answer
323 views

Spatial Analysis - Calculate a cells elevation (height) above the nearest stream cell

I have searched for some ideas on how to formulate this analysis, but have come up short. I imagine there is a pretty straight forward answer; any help would be greatly appreciates. Data: DEM, ...
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2answers
3k views

Viewsheds and Observer Points in ArcGIS Spatial analyst

I am trying to understand the viewshed and observer points tool in spatial analyst. I want to show which areas of land can see a wind turbine, or put another way, from where can the wind turbine be ...
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221 views

Merge overlapping DEMs with irregular boundaries

I have a 10m DEM covering part of a state, a 20m DEM covering the whole state, and a 90m DEM covering the whole country. How can I merge them together, getting the best quality available in each area? ...
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2answers
1k views

Good practice for generating contours from a DEM

We have just received a large set of DEMs at work and I would like to generate contours from them. The DEMs have a resolution of 1m and a size of 1kmx1km. Output from gdalinfo: Driver: ...
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1answer
141 views

Input data format and read multiple files into Grass 6.4.1

I am trying to read in multiple (hundreds, thousand) LiDAR ascii files into Grass. They contain elevation data. I think I have managed one, and I can make a map of elevations, using File, Import ...
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4answers
522 views

How to create a point cloud from DEM?

Please forgive my ignorance if I am asking a totally irrelevant question, I am still a GIS newbie. I looked in Google and found a lot of links as of how to convert point clouds to DEMs. I am trying ...
2
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1answer
547 views

What is the highest obtainable resolution of FREE elevation data in the UK?

I am seeking closure with this question guys. I am aware of various sources of free elevation data ~30+ m, and I have been searching for higher resolution FREE data for a while now. This already ...
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1answer
137 views

How to multiply raster DEM with a linear graph value

I would like to multiply my Raster DEM with a linear graph value y = mx + C. The graph values look as follows: I want to make a new raster where each cell will represent a damage factor from ...
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1answer
146 views

ArcGis--how to lower a DEM's Z value along a line

I'm a raw newbie, so please excuse the ignorance. I'm trying to do the following in ArcGis 10: reduce the Z value of a DEM along a line. My goal is to "etch" a very shallow line into the DEM ...
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1answer
94 views

DEM sources for arctic regions

Are there any 90m DEMs out there for regions north of where the SRTM dataset ends? I looked at ASTER, but it seems to have a lot of unfilled voids, and it's important that the resolution matches the ...
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1answer
39 views

How to export Std Dev from Raster Dataset of DEM to classify current extent and execute Contour Tool with Python?

I want to create Countour Lines for a DEM which are based on a "STD dev" classificaion. My problem is that the "Std dev" is exported in an unknown type instead of a String. So the classifacation for ...
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127 views

Problem with merging 15 DEM files in ArcGIS

I have 15 DEM files downloaded from USGS website. The pixel depth of each file is 32 bit floating, generic with format FLT. I'm then using data Management Tools > Raster dataset > Mosaics to new ...
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1answer
139 views

How to compare accuracy of two DEM using GRASS

How do I compare accuracy of two DEM data (lidar and srtm) (possibly through rmse) using GRASS GIS? thanks
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24 views

How many function templates can be applied to single image service in ArcGIS for Server?

I am trying to minimize space used on our server by producing a single image service for each county in Maryland. However, I need to display 6 different derivatives for each county: DEM in feet, ...
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138 views

What is most suitable DEM to delineate watershed (from spot height, ASTER and SRTM)?

I have three DEMs of our country which are spot height DEM, SRTM DEM and ASTER DEM. SRTM has 90m resolution and ASTER has 30m resolution. My supervisor told me to delineate watershed using these ...
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1answer
97 views

Raster Smoothing python [duplicate]

I want to perform raster smoothing on a DEM file. I want to to assign the elevation of each pixel using the average elevations of its 8 neighbors. The ESRI's "Python scripting for ArcGIS" has a ...
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1answer
359 views

How to join 2D polylines and DEM into 3D polylines?

I got a simple question but could not find a satisfactory answer yet: I have a road network in 2D/PostGIS and a DEM. I want to turn the road network into 3D by retrieving the Z-value from the DEM. ...
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50 views

Multiple metadata within a single mosaic dataset

I am creating a mosaic dataset consisting of thousands of different DEMs. These will make up a single State, however I need the Counties to be able to hold their own metadata. Each raster contains ...
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133 views

memory restrictions in QGIS Interpolate?

I am trying to make a DTM from contour lines (.SHP) using the Interpolate tool. The tool runs fine when I clip the data into smaller areas, but when running for larger areas, it crashes QGIS. Are ...
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1answer
62 views

How to craete DSM? [closed]

I need information on Dsm. Applications and ways to do it and the best software and new methods.
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1answer
155 views

ASTER GDEM v2 coastline generation?

I try to generate world coastline 1:30000 from ASTER's DEM with: gdal_contour -a ELEVATION -fl 0 But above produce some of missing coastlines. Whats happening? Is it cliffy shore? How would you ...
2
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1answer
216 views

How to improve Triangulated Irregular Network (TIN) display speed?

I am preparing Triangulated Irregular Network for large area (5000 Sq Km) in ArcGIS, The TIN models takes too much time to open in ArcMap, and if I move or change anything again its starts to ...
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1answer
112 views

create POV-Ray image from DEM-file in grass

I am working on r.out.pov Tool of grass 6.4 creating a POV-ray(beautiful 3D) image from an elevation raster. You can see this link for more information about 3D analysis of GRASS. r.out.pov manual ...
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1answer
137 views

Split polylines in ramps

I have a shapefile (polylines) of some roads and I want to divide the roads in ramps. Ramp = a piece of the road delimited by the top of a hill and a valley. So, pretending that you're driving in ...
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1answer
861 views

Spatially join large raster to polygon shapefile

I have a large raster file with elevation data. From this raster, I would like to infer the average ruggedness for different geographic zones (like countries). I have the "countries shapefile" as a ...
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91 views

Displaying DEM raster in QGIS

Using Raster>Analysis>DEM to display hillshade produces the message "gdaldem.exe had stopped working" so I asked the community. I'm new to QGIS, and I now realise after a little experimentation that I ...
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1answer
207 views

How do i convert STDS file to ASCII DEM?

I've downloaded several 7.5 minute DEM files from USGS and they have file names like: 1661629.DEM.SDTS.TAR On MAC these decompress into a folder with serval files having the extension '.DDF'. Is ...
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3answers
107 views

Working with GB SRTM Digital Elevation Model (DEM) 90m

I have downloaded the freely available DEM file from sharegeo open. I would like to know for a set of points at what elevation they lie. I have imported the DEM file into ArcGIS but it seems strange; ...
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1answer
117 views

How to set waste water gravitational flow direction using DEM automatically?

I have a Geometric Network of Waste Water and I need to set line digitize direction according to the gravitational flow direction using a DEM. I'm trying to avoid flipping manually 1000 Km of ...
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3answers
5k views

How to smooth a DEM?

I have a SRTM DEM and I want to create a shaded relief from it. I created the shaded relief in GRASS and the result is very nice, but a little rough becouse the area is near flat and the DEM is 90m in ...
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1answer
433 views

How to calculate surface area of highland region using DEM with ArcGIS (ArcEditor)? [duplicate]

Am shyaka from Rwanda. I use GIS tools and have all required data to perform or calculate surface area from the polygons that have been given by GPS (Trimble) with ArcPad 8. I originate from a high ...
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1answer
134 views

Layers not lining up

I have three layers I need to try match up at the borders. This is not a projection problem, all layers are projected to Albers NAD83. The base layer (Green) is 30m DEM, with a US boundaries layer on ...
3
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3answers
286 views

What DEMs does QGIS support? + DEM data sample

I am working on QGIS rasters. I want to know about DEM file formats supported by QGIS. I know that QGIS can read the GDAL supported formats. but what is GDAL supported format ? Does QGIS support the ...
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106 views

How to merge raster quadrangle tiles in qgis?

I've downloaded some dem tiles from here http://www.granit.unh.edu/data/search?dset=dem/dem174, which I'd like to merge into a single smooth digital elevation model usinq QGIS. So far I've tried ...
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1answer
67 views

How do I determine the subsidence of land in Manila, Jakarta and Bangkok?

Can I set how these cities have lost elevation using digital elevation models? Is there a digital elevation model which data are updated? Or are there other methods? Thanks.
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2answers
587 views

gdal doesn´t support my *xyz file

I have just exported a tif DEM to XYZ format with SAGA GIS. When I check this with gdalinfo it states that the format is unsupported? Seeing as I converted this with saga gis which used gdal I find ...
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0answers
305 views

How do I redefine the projection of a DEM?

I have a DEM that was exported from AutoCAD civil 3D 2013 but it's in the wrong projection. I'm using an area specific projection that was not provided as an option in CAD DEM export dialog box. I ...
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1answer
328 views

When merging two DEMs, do they have to be in the same pixel bits?

I have a simple question. I have 2 different Digital Elevation Modeling (DEM). One is the state DEM and has 30m and has 16 pixel bit. I have a couple of smaller DEM that has 30m but they have 32 pixel ...
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1answer
1k views

Labeling contour lines in ArcMap [duplicate]

Can anybody give me advice on how to label contours as shown in Figure 2 below? I would like to be able to put the label "on" the line, which is easy enough. But I'd also like for the contour line to ...
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1answer
655 views

Problem merging two rasters in Qgis

I have two rasters in Geotiff, same CRS. I tried to merge them and I have this error code ERROR 4: `C:/Anita_Tepoztln/Rasters/e142.tif' does not exist in the file system, and is not recognised as a ...
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1answer
107 views

Global DEM and country borders

I am trying to split up the world into 2 categories based on elevation (below 2000m and above 2000m) while still including a country identifier. So in the end, I would like to have 2 types of units ...
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0answers
351 views

How to limit a specific area in order to have a topographic 3D map using MatLab?

I am using MatLab, I want to build a topographic 3D map, I am following this guide, I have been doing the steps listed on the section Draping Geoid Heights over Topography, and I do not have any ...