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

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1answer
114 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 ...
3
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0answers
85 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
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2answers
130 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 ...
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2answers
511 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
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1answer
676 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 ...
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3answers
542 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 ...
6
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3answers
319 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 ...
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0answers
29 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 ...
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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
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1answer
108 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
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2answers
132 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
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2answers
6k 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 ...
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1answer
146 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
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1answer
356 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
109 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
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2answers
150 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
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2answers
7k 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
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1answer
90 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
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2answers
637 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
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0answers
227 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
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1answer
118 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
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1answer
93 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 ...
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2answers
163 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
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1answer
113 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
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2answers
94 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 ...
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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 ...
3
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2answers
392 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
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1answer
270 views

Digitizing contour lines from paper maps using QGIS?

Is it possible to give digitized altitude lines (from paper map) heights using QGIS?
2
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1answer
90 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
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1answer
119 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
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1answer
218 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 ...
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1answer
647 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 ...
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0answers
60 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
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1answer
945 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
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3answers
178 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. ...
4
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2answers
341 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
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1answer
83 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
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1answer
61 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
82 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
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2answers
133 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 ...
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0answers
109 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
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0answers
40 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
419 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
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0answers
55 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
226 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
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1answer
50 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 ...
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0answers
43 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?
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1answer
46 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 ...
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0answers
307 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: ...
2
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1answer
291 views

Gdal/QGIS resampling asc file

I have a DEM (.asc) file with a resolution of 1000 meters per pixel. Therefore the file has a lot of columns and rows. I would like to chance the resolution per pixel from 1000 to 3000 meters per ...