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

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3
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1answer
93 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 ...
1
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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 ...
0
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0answers
124 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
137 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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0answers
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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0answers
134 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 ...
1
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1answer
96 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 ...
3
votes
1answer
345 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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0answers
49 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 ...
0
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0answers
129 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 ...
-1
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1answer
61 views

How to craete DSM? [closed]

I need information on Dsm. Applications and ways to do it and the best software and new methods.
2
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1answer
147 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
202 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 ...
0
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1answer
108 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 ...
6
votes
1answer
136 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 ...
1
vote
1answer
818 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 ...
2
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0answers
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 ...
2
votes
1answer
187 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 ...
2
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3answers
105 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; ...
3
votes
1answer
116 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 ...
24
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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 ...
0
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1answer
410 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 ...
1
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1answer
128 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
votes
3answers
278 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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0answers
100 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 ...
0
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1answer
65 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.
3
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2answers
573 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 ...
0
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0answers
297 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 ...
5
votes
1answer
326 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 ...
5
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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 ...
1
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1answer
627 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 ...
1
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1answer
106 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 ...
2
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0answers
333 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 ...
2
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1answer
264 views

How to find area of Digital Elevation Model above/below a reference plane?

I am using ArcGIS10. I need to find the out the area which is below 5000 and above 5000 from the Digital Elevation Model which is available to me. How can I find out this ? My DEM ranges from 8848 to ...
0
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1answer
57 views

About getting area from DEM below 5000 and below 3000 m elevation? [duplicate]

I want to get the area from the DEM which is below 5000 and 3000. Actually I need those two areas for my Regression Model to calculate the discharge. In that case, how can I find out using python. I ...
9
votes
2answers
708 views

Floodplain generation given river section polylines, flood level elevation points and a DEM of the land surface

I am looking to generate flood plain polygons to represent 20 and 100 year flood zones, in the most accurate and efficient way possible, given the following datasets: 1) River cross section polylines ...
0
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0answers
77 views

3D Polyline by Slope on Surface

I wish to project (continue/extend/whatever) a polyline upslope following a specified gradient along a DEM surface. Is there any way of doing this?
13
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1answer
458 views

Creating nanoscale DEM with GDAL

A bit of a strange question perhaps, but let me give you a breif explanation of the background before my actual questions: Atomic force microscopy (AFM) is a method that, in short (and to my limited ...
37
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7answers
35k views

What is the difference between DEM, DSM and DTM?

I am listing some of the acronyms used in our work and had to stop to think about whether to list these together or separately. In some circles they are synonymous, in others they have distinct ...
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1answer
220 views

Overland flow modeling Help

I would like to determine the surface flow network, this based on the spatial analysis of DEM data and the creation of separate layers for surface ponds and preferential surface flow pathways. More ...
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1answer
71 views

rooftop modeling

I´m trying to model building rooftops based on a LiDAR dataset. I've already interpolated using Delaunay's triangulation a DEM with 1m resolution. Due to LiDAR data is not accurate in building edges, ...
3
votes
2answers
5k views

Viewing .las format LIDAR data in QGIS?

Is there an easy path to visualizing this LIDAR data? I have QGIS, and some USGS LIDAR data in (.las) format downloaded from http://lidar.cr.usgs.gov/ . This means I have both the (.las) and ...
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1answer
162 views

Volume of Land Below Sea Level

How could one use a GIS (or other appropriate system) to calculate the change in mean ocean levels across the world if all the land below sea level were flooded (Death Valley, Caspian Depression, Afar ...
4
votes
2answers
122 views

How to create a single contour defining the boundary between sea and land

Hello! I am still learning so forgive me if my question is very simple... I am trying to create a map with ArcGIS. The area I am working on is a seasite and I found that in some parts the cells appear ...
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0answers
138 views

Error Message Orthorectifying ASTER Imagery in ArcMap 10 with DEM

I am trying to orthorectify ASTER imagery (VNIR, 15m resolution) in ArcMap using an ASTER DEM that I have downloaded from the GDEM website. The area is in the Andes, there are very high elevation ...
5
votes
4answers
2k views

Definitive source for downloading DEM data

USGS has been moving towards serving data through The National Map Viewer. They have several WMServices through their website that serve elevation data to the public (hillshade & DEM). The ...
4
votes
1answer
549 views

Zonal Statistics for Polygons with R

I'd like to do zonal statistics / terrain analysis with polygon overlays - I achieved to get min / max like so: library(raster) library(rgdal) alt <- getData('alt', country = "AT") gadm <- ...
4
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1answer
319 views

How to calculate the volume of several DEMs to obtain elevation and volume changes?

I am trying to calculate the volume of several DEMs in order to obtain elevation and volume changes. I have pixels of 1x1 each one associated to an elevation. I used several methods but non of them ...
0
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1answer
109 views

How to select a subset of a DEM in ArcScene?

I'm using ArcGIS 10.0 and trying to open a digital elevation model in ArcScene. I'm working on a project and got the DEM data from official sources which is quite huge. The resolution of the DEM is 1 ...
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0answers
212 views

tools from Geospatial Modelling Environment in ArcMap model [closed]

How to extract raster DEM elevations to vector attribute tables in ArcGIS 10? Can GME tools be used in model for publishing a tool on web? I want to use it in integration with other tools in ArcMap. ...