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

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15
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2answers
2k views

Generating contours from DEM using GDAL?

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: AAIGrid/Arc/...
0
votes
0answers
26 views

Apply mask on ERDAS LPS

I am currently working on my final year dissertation and most of it is done on LPS. I am using Cartosat-1 and ALOS PRISM imagery to create DTMs for an area that is located on a peninsula. The problem ...
0
votes
0answers
71 views

erdas LPS : Load Z values from a DEM?

I'm working on a photogrametric project with erdas LPS version 2013. I succeed in taking several ground control points (x and y values). However, i can't extract and load Z values from my raster DEM ...
0
votes
0answers
25 views

Orfeo Toolbox DEM download error

I have been trying to use the following part of the Orfeo Toolbox to download DEM data from usgs. I have been passing it a geotiff image as the reference and am receiving the following error: 2015 ...
2
votes
1answer
2k views

How to extract DEM files from google Earth/Map for surfer?

I will need to do a 3D representation of a terrain and I heard surfer is ideal, but then I do not have a DEM file of the region, I know Google Earth and Map could help, but I do not know how? If there ...
0
votes
0answers
127 views

How to make DEM raster in Google Sketchup?

I would like to make DEM in google sketchup, later add 3D buildings and finally convert this file to raster. Afterwards, I want to import this raster to GRASS GIS to make solar maps. It is possible to ...
1
vote
0answers
68 views

Las tools vs Geocue for LAS1.3 processing [closed]

I am a user of terra solid products. I have las1.3 data set which i need to perform whole processing in 1.3 version. (I need to supply WDP informtaion and classified las dataset as well. So I afraid, ...
3
votes
4answers
234 views

How can Identify highs on a DEM?

I have a DEM and I want to find each hill and create a polygon for its area, effectively the out closed contour that encloses the hill. I can do this visually but I'm about to work on a larger area so ...
2
votes
2answers
838 views

automatically geo- and ortho- rectify raw Landsat data using DEM

I have a dataset of 20 Landsat scenes (MSS, TM, ETM+) for 20 years (one scene per year). Scenes are in WGS 84, EPSG 32634 coordinate system and I can easily project = geometrically correct them to ...
2
votes
0answers
665 views

GDAL tiling DTED (dt2) dataset as gdal2tiles for 3D Maps

i am searching some webgl technologies to create 3d map with digital elevation data. for web tech. i have found ReadyMap SDK to create 3d map from TMS... in ReadyMap for elevation data it uses sth ...
0
votes
0answers
12 views

Where to find free DSM data of Switzerland (Ticino)? [duplicate]

I am working on a sonification project. My aim is to sonify data coming from a delimited area in Switzerland. I also would like to print out a 3d map of that region based on that data. Problem is : ...
1
vote
0answers
70 views

How to extract area information from a raster based on a DEM or contour lines

I have a raster representing the distribution of a specific land cover type - the raster values are 1 for where the land cover type is present and 0 where it isn't. I also have a DEM with 5m ...
5
votes
1answer
175 views

How to run a tool from Whitebox GAT in ArcGIS?

I have a series of tools that I need to run in ArcGIS to hydrologically condition my DEM, but the first step in this process is running the Breach Depressions tool from Whitebox GAT (I have found that ...
19
votes
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 ...
7
votes
2answers
2k views

Splitting raster into smaller chunks using GDAL?

I have a raster (USGS DEM actually) and I need to split it up into smaller chunks like the image below shows. That was accomplished in ArcGIS 10.0 using the Split Raster tool. I would like a FOSS ...
0
votes
1answer
210 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 ...
4
votes
2answers
180 views

How to export a polygon based on elevations using a DTM or a DEM

I have a LiDAR generated DTM and a DEM (accurate to 10x10 feet). I am trying to export a polygon within a boundary which includes all elevations below a specific number. Seems like this should be ...
2
votes
0answers
41 views

Mosaic DEM has large pixel when displayed in ArcMap?

I created a mosaic dataset in ArcMap 10.2 from tiles of ASTER DEM's at 30m resolution. I am attaching the image of what my export looks like. You can see that there are extremely large, alternating ...
2
votes
1answer
2k views

Converting mosaic dataset to TIN gives error? [closed]

I merged several DEMs together in on single DEM with mosaic dataset. Now I wanted to convert this mosaic dataset in Vector with TIN. But when I use the tool (3D Analyst Tool) Raster to TIN comes an ...
2
votes
1answer
63 views

How do I find out the sea levels?

I have following elevation data of a region (the higher the altitude, the brigher the points): How can I find out, which areas are filled by water, and which not? Can I assume that if the ...
2
votes
1answer
159 views

3D model of rooftops based on LiDAR and cadastral data?

I´m trying to model building rooftops based on a LiDAR dataset. I've already interpolated using Delaunay's triangulation a DEM with 1 meter resolution. Due to LiDAR data is not accurate in building ...
0
votes
1answer
79 views

Is there a way to Alter Elevation Values of Pixles of a DEM based on BM and Control point elevation from actual Field survey?

We have got a quick bird DEM of our site. After getting actual on ground elevation values with a differential GPS device, we have found that there is a difference of average 12 feet between DEM and ...
0
votes
0answers
54 views

Resampling and snapping DEM to match a second raster

I have a DEM that is derived from a 50K map (provided by Geobase Canada), the resolution indicates it is 23.19156058m per cell (raster name DEM_50K). I need to resample this DEM to a 100m cell size (...
0
votes
1answer
41 views

Dtm format save only heights

I need dtm format that store only heights and scaling and left up position for saving storage I glad to know if any stadard save heights that way
5
votes
1answer
128 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 ...
11
votes
2answers
481 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 ...
2
votes
1answer
62 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 ...
0
votes
2answers
56 views

Equidistance on line contour from DEM

I am using a SRTM 30 meters for slope and elevation. When i'm using this 30x30 rasters to generate contours i set a 30m equidistance for contour, and the results are ok. Now i'm wondering if it's ...
4
votes
2answers
646 views

Stitching Bathymetry and DEM data together in ArcMap?

I have a DEM built from Lidar data and bathymetry survey points for a river which flows on the DEM surface. My understanding is that Lidar data is not able to capture bathymetry under the river flow....
3
votes
1answer
370 views

SAGA tool 'Relative Heights and Slope Positions' - What do results tell me?

I am currently trying to get in morphometry, using the SRTM 30m DEM. I was recommended to test the SAGA mudule 'Relative Heights and Slope Positions' (http://www.saga-gis.org/saga_module_doc/2.1.3/...
4
votes
1answer
130 views

Raster cells with no data being generated by las2dem?

Anyone has an idea where these lines (with no elevation data) come from? They are generated while using the las2dem tool from LAStools. What needs to be done to avoid this? The raw data (.las file) ...
0
votes
2answers
67 views

Update raster pixels on a DEM

I have a DEM in the form of a raster that I would like to update in certain locations. Ideally, I'd like to be able to create a separate polygon or point shapefile with the values, in the correct ...
1
vote
1answer
19 views

In QGIS, add to existing dem tiles and expand corresponding contour coverage within a project

In my first QGIS project I have dozens of digitized layers that have spread beyond the contour and dem tile area that I started with. Please recommend how to safely expand or replace the dem and ...
0
votes
2answers
972 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 ...
2
votes
0answers
28 views

Combining multiple DEMs into one file geodatabase

I have multiple file geodatabases (approximately 240) each contain a DEM. My issue is taking the DEM from each and putting it into a single file geodatabase without alot of mind numbing work. ...
1
vote
0answers
46 views

Quantifying amount of sunlight falling in a region

I am trying to objectively quantify or provide some form of indication that could point toward the amount of sunlight Anyone knows if there are any datasets (either instrumental or remotely sensed ...
3
votes
1answer
68 views

Simplify / generalization of flow lines

I'm trying to make a model of surface runoff of rain water. I'm using GRASS GIS function r.flow, which generates nice smooth lines of runoff. What I need is edit these flowlines someway to avoid ...
0
votes
0answers
65 views

how to define threshold value in r.stream.extract

I want to generate streams using r.stream.extract. on what basis we have to define the threshold value. I am using aster dem with 30m posting.Also i want to know the minimum stream length to be ...
6
votes
4answers
713 views

What are the most efficient Geographic Weighted Regression packages?

What are the most memory efficient open source packages for calculating a geographically weighted regression (GWR)? I am in a situation where I need to do a geographically weighted regression on a ...
6
votes
1answer
442 views

Problems creating TIN from British Columbia DEM data

Is anyone familiar with creating a TIN using ArcGIS9.3 and British Columbia DEM data (.GEN files)? I can't figure out how to get the breaklines to work during the creation of the TIN. Using ...
10
votes
3answers
3k views

Create DEM from stereo pairs using ArcGIS for Desktop or Open Source GIS?

Does ArcGIS Desktop or any of its native extensions allow me to create DEMs from stereo pairs (acquired by satellite, GeoEye 1)? If the answer is a clear no, brownie points will go to an answer that ...
0
votes
0answers
17 views

Extracting Elevation (DEM) from air photos using open source software? [duplicate]

I have a few pairs of stereo air photos and I want to extract a DEM from them. I think that is possible using PCI (OrthoEngine), but I would like to do it using Open Source (or at least free) ...
2
votes
0answers
129 views

High Resolution Terrain Data for the Philippines

Where can i download Philippines terrain data that is better than the 30 m ASTER global dataset?
1
vote
2answers
120 views

Topographical Elevations for Central Africa and Cameroon

I am using QGIS and I have been faced with the problem of topographical maps. From searching online I could only find data for the United States. Google maps offers elevation contours, however I am ...
2
votes
2answers
438 views

How to extract elevation values at line start and end points from a DEM?

I am new to the whole gis-experience and need your help working with QGIS. I have: DEM raster with heights (3d) line-shapefile which contains the rivers (2d) I need: heights for "start" and "end" ...
2
votes
1answer
2k 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
vote
0answers
40 views

Z factor to get the results in square meters and cubic meters?

I have a DEM surface in WGS 1984.I want to calculate surface area and volume in different elevations.I wonder for example If I want to measure the area and volume below some height how shall I set the ...
0
votes
0answers
33 views

ASTER data error causing “bumps” in elevation

I am working in ArcScene (10.1) with some 30m resolution ASTER data from Indonesia, and am getting anomalous "bumps" in elevation in my study area. In google earth it is not there, and I know from ...
1
vote
2answers
392 views

Masking out places with elevation below 5 m from a DEM

I have a DEM of a study region; I want to modify the DEM in order to reflect the coastline outlook when the sea level was 5 meters higher than today. What I have done so far is to use 'Raster ...
0
votes
0answers
31 views

Is there an existing tool or plugin to automate the elevation versus volume relationship of a dem within a user provided polygon

I often need to obtain the elevation versus volume data for a proposed basin site but have not found a truly automated solution. I would simply like to create a bounding contour polygon of the DEM ...