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

learn more… | top users | synonyms (2)

1
vote
1answer
42 views

QGIS 2.6.1: “no enhancement” option not working on DEMs

When I import DEM raster layers and try to change the contrast to "no enhancement" I get a blank white image in the map window. Changing "black to white" to "white to black", the map remains a blank ...
3
votes
1answer
408 views

DEM creation with C++ application

I am implementing a C++ application that must produce DEMs from LIDAR data. I am following the next workflow: Write .las files from lidar data. Use PCL algorithms to transform/filter the point cloud....
2
votes
1answer
246 views

SRTM DEM with 16 bit signed pixel type changes to 32 bit float when creating slope/aspect/curvature

I have mosaiced 8 SRTM DEM tiles in order to get one raster layer of elevation. When I use "Mosaic to New Raster" tool I set as a pixel type format "16 bit signed" because this is the format that SRTM ...
1
vote
0answers
111 views

Displaying a Digitial Elevation Model using GRASS GIS draped by an RGB Raster

I have the following: Digital Elevation Model from SRTM LANDSAT Imagery from the same area I wish to display the DEM draped with the raster band combination (3,2,1) using GRASS GIS. My ...
1
vote
1answer
300 views

Changing the Axis on a Profile Graph

I'm working on a map with forest trails and I want to get an elevation profile of them all individually. I have gone through and interpolated the trail layer with a DEM so that I can use the 3D ...
0
votes
1answer
246 views

What is a DTM in Grid format?

A client asked us for a group of files of DTM in Grid Format. And my question is, what is this DTM in Grid format? O maybe its same of DEM? Is it possible to convert from DEM gray scale format to ...
7
votes
6answers
1k views

How can I convert a DEM into areas of “flatness”, with an arbitrary fill/cut to area ratio?

I want to find areas of relative "flatness" in a DEM. How can I find flat areas? I want to find a neighbourhood of contiguous cells that have an elevation variance that is within a certain ...
3
votes
1answer
223 views

Correcting for local topography in calculating TRI from DEM in ArcGIS

I'm currently investigating the use of different equipment in calculating TRI from elevation data using ArcGIS. From the methods available (http://gis4geomorphology.com/roughness-topographic-position/)...
2
votes
4answers
515 views

How to calculate RMSE, skewness, and kurtosis of raster image?

I'm doing a project to analyze the impact different interpolation techniques plays on DEM accuracy. In order to do so, I need to calculate the RMSE, skewness, and kurtosis. I have: an original ...
0
votes
1answer
377 views

How to add image(.jpg) to OpenLayers?

This is my website for test: http://www.cv.nctu.edu.tw/shapefile-js-openlayers/ol_simple.html My dem data is (.jpg). var inProj = new OpenLayers.Projection('EPSG:3826'); var outProj = map....
2
votes
1answer
264 views

GeoserverTerrainProvider plugin displays faults in elevation tiles

I try to display elevation data using the triple Geoserver/Openlayer3/Cesium. It seems I have the same problem than http://stackoverflow.com/questions/25936968 and for now, I can not get a working ...
3
votes
1answer
256 views

gdal_grid - fails to find layer and field

I'm using gdal_grid for the first time and get this issue: gdal_grid -zfield field_3 -l layer0 OLEX-LAT-190952014.vrt OLEX-LAT-190952014.tiff ERROR 1: Failed to find layer 'layer0' on datasource '...
1
vote
0answers
84 views

How to resample a DEM from GCS to UTM with respect to reprojection bounds parameter?

When reprojecting a DEM (e.g., SRTM-derived 1-arc DEM) using PCI Geomatica for example, to constrain pixel size and maintain a square pixel you can either change the image extent or the number of ...
1
vote
0answers
170 views

How to do a flood simulation without flooding the whole area and covering surface structures (with DEM)?

I have a high resolution DEM and want to do a flood simulation starting at a river. My hope is that the water runs into historical (now dry) river channels (in which I'm interested in) at first and ...
4
votes
3answers
252 views

How to resample a 30m DEM to a 100m slope raster properly?

I need to resample a 30m DEM to a 100m slope raster. Do I just resample the 30m DEM directly to the 100m slope raster? or, do I convert the 30m DEM to a 100m DEM and then create a 100m slope raster ...
2
votes
1answer
213 views

filter / generalize elevation points on the basis of some conditions

I wanted to generalize many elevation points in a rectangular area (about 700 square km). I need to take about 3 points for square km. These points must satisfy some conditions: One of these ...
0
votes
2answers
2k 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- ...
10
votes
1answer
22k views

creating a dem from contours

I have a large set of contours that I received broken down into several different subsets. I have merged most of the subsets together creating a larger set of contours in three different files. I have ...
0
votes
0answers
78 views

byte swap a mosaic raster

I'm getting into trouble to byte swap a raster. I'm using two DEM rasters that I mosaic using the function "mosaic to new raster". The new raster I get is called "mosaic". The cell range then shift ...
4
votes
1answer
234 views

Convert Whitebox .dep to ArcMap DEM .tiff?

I am having difficulty converting my whitebox raster float file to an ArcGIS raster file in ArcMap 10.2.1 I followed the protocol outlined at: http://www.uoguelph.ca/~hydrogeo/Whitebox/Help/...
-1
votes
1answer
85 views

How to decrease elevation values of DEM using open source GIS sotware? [closed]

I am newbie in QGIS, but I was wondering how to decrease elevation dem DEM using QGIS? Can QGIS do that? Or anyone of you can tell me any open source GIS software to perform that?
4
votes
5answers
3k views

Problems merging DEMs or other raster datasets? Clipping Raster dataset to vector line?

I have two DEMs that I am going create a hillshade from, and ultimately want one hillshade clipped to a county boundary. I am running into a couple problems, though. When I try to merge the two ...
2
votes
3answers
1k 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 ...
3
votes
3answers
2k views

Creating DSM and DTM from a LAS using a freeware solution

Is it possible to export a surface and terrain model files from an aerial, LiDAR point cloud (LAS) set? I am using SAGA GIS for very basic operations, but I couldn't find this option (and I have a ...
3
votes
2answers
892 views

Where to download 10m (1/3 arc-second) DEMs?

I'm looking for some of the 10m DEM to fill in the white Quad areas. Do you know where of can I find them? These 10 DEMs we have are actually coming from the NRCS Geospatial Dataway. I believe they ...
1
vote
3answers
3k views

Downloading 1 arc-second elevation data for Canada other than Geobase?

Can someone suggest a source for Canadian elevation data better or equivalent to 1 arc-second? I have a good data source for Ontario but for other provinces folks often recommend Geobase which claims ...
4
votes
1answer
887 views

Is it possible to reverse the trend/values of a raster?

For example - if I have a raster DEM covering a stream with higher elevations in the west (up river) and lower elevations in the east (down river) is it possible to reverse this trend so that the east ...
0
votes
1answer
28 views

Raster Files Sizes from Point Data Extremely Different

Using ArcGIS 10.1. I created rasters from several groups of point rasters using the Point to Raster tool. All of the points groups are similar size and extents. The first group of points had a file ...
6
votes
2answers
454 views

Burning road network into DEM?

Does anyone have any suggestions for burning a road network into a DEM? I have a python script written up for this executing this in ArcMap, but I would love to hear if anyone knows of any freely ...
2
votes
3answers
185 views

Where can I find open source bulk US DEM or imagery?

I am looking to create terrain hillshading for my maps that contain a small region of the US. I intend to show about eight to ten states at a time (at about ~1:5,000,000 scale). It has been some ...
2
votes
1answer
55 views

Disable Mosaic Overview Information When Using Identify Tool

I have a created mosaic datasets using elevation data. When I add this data to ArcMap and use the identify tool it brings up information about both the footprint and image. At full extent the ...
2
votes
2answers
131 views

ArcGIS, mosaic first or calculate first

I'm working a set of 30meter DEMs (~40 DEMs) for New England. I've seen a lot of debate on whether to work with (A) the individual DEMs first, and then mosaic the final raster calculations together, ...
3
votes
1answer
307 views

How to subtract out the slope (in general) of a DEM?

I'm searching for a solution process to subtract out the slope of a DEM like this: I have a high resolution DEM and want to reconstruct historical/old/not active parts of a river. The problem is ...
1
vote
1answer
219 views

mosaic dem with multiple coordinate systems

I'm sure this is a basic question, but I'm struggling to mosaic multiple DEMs (~40) into one large raster. The DEMs are 30m NED rasters from the NRCS data gateway, for the New England region. They are ...
6
votes
2answers
183 views

How to automate creation of toe of slope from DEM?

I was looking for an automated process to "identify" the toe of a slope from a DEM and ran across this ESRI thread and technique: I am at Step 7 but have no idea how this is accomplished. I get it is ...
1
vote
2answers
709 views

Can I prevent QGIS raster clipper from changing output cell/pixel size?

I have performed a DEM extraction using the clipper tool in QGIS 1.9.0 Master, using a mask layer, the original resolution of the DEM is 20x20 but in the resultant DEM the new resolution is 19.98x19....
6
votes
1answer
731 views

Interpolation: irregular shape, merging DEM's

My problem is quite complex, but I hope that solution may be simple or at least possible. I do have .img DEM 0.5x0.5m. DEM consists of river bed, river valley and adjacent areas (it is strip of 5km ...
3
votes
3answers
1k views

How to calculate peaks in a DEM

How could I extract all peaks from a DEM (large mountainous area)? Peak means something like: a pixel which is sourrounded by other pixels with smaler elevation numbers in a area arround the "peak-...
1
vote
0answers
42 views

findind depression in cloud point and dtm

I would like to find temporary moist areas based on terrain surface shape (depression) directly from cloud point data (ALS) and DTM. Could you help me to find some tools or algorithm to solve the ...
3
votes
1answer
136 views

how to extract elevation data using a DEM

I have digitized an LULC layer from satellite imagery, now I want to extract the elevation data from it. I have obtained DEM images from SRTM amd ASTER. How do I proceed?
3
votes
2answers
256 views

downloading DEM for free

I need to download a DEM in WGS format for Nepal ( around 86 degrees longitude and 27 degrees latitude), that can be exported to a GIS as raster for analysis. Does anyone know of any good, free data ...
3
votes
2answers
8k views

Replacing Raster Values in Ras1 with Ras2

I have two rasters Ras1 and Ras2. I want to change the Ras1. In Ras1, there are few areas, lines, points I am interested having nodata cells and wrong data cells.(limited to interested areas only ...
0
votes
1answer
180 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 ...
5
votes
1answer
381 views

Merging two DEMs in different pixel bits?

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 bit. I know how to merge ...
3
votes
1answer
381 views

Relocating & resizing complex shapefile with OpenSource Software

(please excuse my poor english) I do have a polygone shapefile of an archaelogical site with elevation data of 10cm steps and I dont get hands on the raster data as it was collected by the drone. My ...
4
votes
2answers
269 views

How can I smooth or resample a DEM to find steep roads?

I am trying to find sections of road with steep gradients. My process is: pull a linestring from Openstreetmap data resample it to create a point every 10 metres look up the height data for each ...
7
votes
2answers
9k views

Creating DEM from point data in CSV files using ArcGIS Desktop?

I have a lot of csv files which contain point data containing height, aspect and slope measurements at a resolution of 12,5 meters. I need to create a dem from this data and have ArcGIS 10 with ...
2
votes
1answer
156 views

Problem or ERROR in converting from raster to vector!

I wonder if anyone could help me out, i am kind of a beginner at QGIS. I´ve built a DEM for a project that i am developing than i´ve made the slope raster with the terrain analysis,it seemed that ...
2
votes
2answers
1k 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, 1/...
2
votes
0answers
559 views

Along a line create profile/cross-section lines then extract elevation points from them

I know that maybe this question has got an answer, but I need to extract elevation data from a line of a defined length (p.e. 300 meters). Also I want the software (QGIS or ArcGIS) to draw this lines ...