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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0answers
69 views

DEM from contours

I have problem to create a DEM from contours. I know it is very simple but I can not make it work. I tried everything but nothing has happended! The shapefiles I've got are a con_lin and a con_pol ...
5
votes
2answers
118 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
427 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 ...
6
votes
1answer
663 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
445 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 ...
4
votes
3answers
241 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 ...
5
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0answers
95 views

Extract DEM and DTM information from LIDAR image using E-Cognition

I´m trying to extract DEM and DTM from a LIDAR file. I just rasterize the image but then I don´t know which algorithm I need to apply to obtain the DEM and DTM information in different models to be ...
1
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0answers
25 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 ...
20
votes
8answers
1k views

How to generate a random but believable digital elevation model?

Is there a way to generate a DEM, programatically or otherwise (arcpy or R?), that will feed into ArcGIS for further spatial analysis? Perhaps this needs to be broken down into smaller incremental ...
3
votes
1answer
88 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?
2
votes
2answers
86 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
5k 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
136 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 ...
4
votes
1answer
247 views

DEM local adjustments - terraforming

I'm looking for software that can perform local adjustments in DEMs with tools similar to paintbrushes used in graphics editing programs but streamlined to respect geomorphology. To give you an idea ...
5
votes
1answer
351 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
58 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 ...
3
votes
2answers
116 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
6k 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
68 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
510 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, ...
2
votes
0answers
150 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 ...
0
votes
1answer
78 views

Building heights above DEM through field calculator

I have a series of building polygons which I would like to convert to a raster illustrating their height. I have the building heights but not their elevation above sea level datum. I have the ...
1
vote
1answer
68 views

Adding items to DEM in QGIS

Working with QGIS and Grass I would like to produce a ZTV. I have the bare land DEM happily ready to go but would like to add buildings and woodland to the calculation. Can anyone please point me in ...
2
votes
2answers
102 views

How to calculate percentage of selected area from DEM?

I am working with elevation data and performed a local operation to convert it from meters to feet. I am interested in finding the area (expressed in percentage) that is above 4000 ft, but I have ...
1
vote
1answer
90 views

Learning about bathymetry?

Besides reading about bathymetry, I would like to work on some hands-on training that I can learn about bathymetry. Is there any good bathymetry out there that I can get some training with the ...
2
votes
2answers
79 views

ArcGIS are two rasters the same? - including null values

I am working on a task to calculate Height Above Nearest Drainage (HAND) - that is the height above the nearest point along the flow path that is on a drainage - not the geographically nearest ...
0
votes
0answers
24 views

Looking to fine the average slope within a polygon [duplicate]

Question not a duplicate.. please help; I am using ArcGIS 10.2 (not open source software) and I have a high resolution DEM, 1.0m resolution, and I am looking to find the average slope and range of ...
4
votes
2answers
266 views

How to fill sinks in DEM with specific amount of water

I identified the sinks in my terrain based on the DEM (grid) by using the 'fill'-tool and substracting the original DEM from the filled DEM. I also identified watersheds as well as flow paths. Now i ...
4
votes
1answer
201 views

Digitizing contour lines from paper maps using QGIS?

Is it possible to give digitized altitude lines (from paper map) heights using QGIS?
2
votes
1answer
76 views

Calculate Height Data From Three Known Points

What's the best way to calculate "height" (snowfall, actually) data from three surrounding locations? For this example, I'm looking to arrive at a "close enough" snowfall value at point A by ...
1
vote
1answer
83 views

How do I convert a TIF to EPSG:3857

I'm trying to convert this TIF to EPSG:3857, but when I run: gdalwarp -of GTiff -s_srs epsg:4326 -t_srs epsg:3857 -co "tfw=yes" original.tif converted.tif I just get a black TIF do you know what I ...
2
votes
1answer
91 views

How to reproduce contour-style labeling with rasterVis::contourplot?

I am currently working with a digital elevation model (DEM) of Mt. Kilimanjaro, Tanzania. The referring raster grid can be downloaded from DIVA-GIS (Country: Tanzania; Subject: Elevation). After ...
1
vote
1answer
310 views

Generating a Mesh from DTM

Are there any tools that can take a DTM, in asc or geotiff format and generate a mesh from this that can used in meshlab or similar software. I have asc DTM file that I need to convert to a ply mesh ...
1
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0answers
46 views

hillshade and slopeshade geotiffs fail to convert to new projection using gdalwarp

I'm trying to convert my three DEM products (colour, hillshade and slopeshade; the latter two generated using gdaldem) from EPSG:4326 -> EPSG:3857 using gdalwarp, via the command: gdalwarp -of GTiff ...
6
votes
1answer
879 views

How to calculate te area between contour lines on a DEM with QGIS 1.8?

Does anyone know how to calculate the area in km² for each altitudinal band (between 100 and 200, 200 and 300...) based on a DEM? I added the contour lines with a distance of 100 metres but could not ...
4
votes
3answers
127 views

Which raster resolution (DEM) can I get out of lidar data with variable grid width?

I have ASCII files in *.xyz format and want to generate a DEM out of it. According to the information about the data the *.xyz files are containing variable grid widths - from 1 meter to 4 meter. ...
3
votes
2answers
237 views

How to create a raster tiff (dem / heightmap) from a mesh of xyz points?

I have to create a terrain heightmap(raster tif preferably) from mesh of xyz ungridded points(in geographical coordinates), I tried taking min and max of bbox of mesh and making width & height by ...
2
votes
1answer
70 views

Calculate regional slope from DEM

I need to calculate regional slope for a coastline using a ~500 meter DEM covering a coastal plain and continental shelf where the slope for each grid cell is calculated by defining elevation extremes ...
1
vote
1answer
46 views

How to make raster DEM from SHP with FME?

I have a Point Featureclass in an ESRI FGDB with 22 Million points. The points have a distance of 10m from each other.I would like to create a raster DEM using SAFE FME 2014. Looking at the ...
2
votes
1answer
65 views

Converting Aspect degree to westness

I have extracted Aspect values in degree from DEM in ArcMap 10.2 full license. I want to investigate effect of Westness in my model so I was using conversion formula of Folded Aspect : ABS (180- ...
1
vote
2answers
110 views

Producing GIS data from large amount of ASCII DEM files?

I have just received a large amount of ASCII DEM files. In total 564 Files each containing 40,000 point data (22.560,000 Points). I would like to convert this into a point cloud with a view to ...
1
vote
0answers
60 views

How to fill empty pixel from DEM using QGIS?

Is it possible to fill empty pixel from DEM (hgt file)?) in QGIS ? When I load it, and zoom to a big scale, some pixel without any value appear. ( I have found a way using another software 3DEM on ...
2
votes
0answers
33 views

How to efficiently drape vector data over a DTM

I have ~100 million 2d vector topographic features (lines and polygons) in an Oracle 12c database. I have 20 billion xyz points in an Oracle database table as number types - the points cover the same ...
2
votes
1answer
259 views

QGIS 2.6 - Point Sampling Tool plugin producing empty shapefile

I use a DEM file (*.tif) and a points layer. My need is basic : getting the Z value for each point by extracting them from the DEM. Both layers correctly opened with QGIS 2.6. The DEM returns a Z ...
2
votes
0answers
39 views

Extracting DEM from IFSAR

i have this IFSAR data (.img) and i dont know where to start. how do i extract DEM from this data? Do I need to go through a Remote Sensing software (ERDAS or ENVI) or i can simply use ArcGIS? and how ...
2
votes
0answers
177 views

Error 5 Pixel type must be FLOAT32

I am trying to create a DEM from topographic contours vector. I have already sucessfully created a raster using the interpolation plugin. Firstly, I don't know why or how to ccontrol the output ...
2
votes
1answer
39 views

Resolution of NED (National Elevation Dataset)

I downloaded some DEMs from the USGS with a resolution of 1/3 degrees for different areas in the US. Now I am looking at the files and saw that all DEMs have the same number of columns and rows. I ...
1
vote
0answers
37 views

How do I reduce contour intervals (i.e. from 50m contours to 10m contours) without using DEM?

I have shapefiles (lines) of contours having 50m intervals. How can I reduce the intervals to 10m without first converting the 50m contours to DEM?
1
vote
1answer
40 views

What is a better idea for modelling a fault plane than as TIN? [duplicate]

I am working on a project which runs on ArcGIS platform using VB.NET. It is to model a sub-surface fault plane (currently a plane rectangular model with some dip) and then to find required distances ...
1
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0answers
215 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: ...