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

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1answer
46 views

Query DEM Elevation at Point in QGIS

I'd like to be able to pull up a DEM (or create a mosaic of them) and simply query the elevation at points I click. Is this possible using QGIS?
4
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1answer
114 views

How to extract DEM (Digital Elevation Model) from 3D model

How can I extract a Digital Elevation Model from a 3D model of a building, made with SketchUp, using Blender,qgis or any other software?
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2answers
155 views

How to use OS Terrain 50 in QGIS

I am new to GIS and I wish to perform view shed analysis of wind turbines from a DEM. I have downloaded OS Terrain 50 and the data is contained within numerous zipped folders. I am using a Mac with ...
3
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1answer
148 views

Highest DEM pixel in polygon

I'm working with QGIS and have a big DEM raster layer with height information and a vector layer with many polygons, representing 1 x 1 degree tiles. Now I want to find for every polygon the highest ...
4
votes
1answer
509 views

Drawing irregularly shaped boundary polygon around set of LAS points using ArcMap?

I am working with a set of LAS data which is irregularly shaped, picture a starfish as the point coverage, surrounding the starfish may be water on one side, may be more land elsewhere but no points ...
4
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1answer
277 views

Generate channel network (rainwater run off) - which algorithm is the best?

I want to compute DEM for a whole country (cca 79 000 sqr. km) and I need to be hydrologically correct as much is possible. After, for this correct DEM I need to compute drainage lines of surface ...
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0answers
97 views

Correlation between point feature (disease) and elevation

I have a problem! How can I calculate the correlation between point feature and Dem raster? Hypothesis: disease prevalence in high altitude is more than low altitude. I must do this in ArcGIS 10 and ...
2
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1answer
82 views

How to convert ASCII in x,y,z format using gdal_grid?

I have a map saved in (AFAIK) Arc/Info ASCII format and I would like to convert it with gdal grid but I am getting errors. My data (p.csv) is in the following format: 319053.25,319301.12,544.28 ...
2
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2answers
114 views

What is the source of horizontal and vertical striping in USGS DEMs?

When processing 30m and 10m DEM data downloaded through the National Map Viewer from the National Elevation Dataset, we noticed horizontal and vertical striping not only in the produced results, but ...
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0answers
50 views

Developing a Slope Map of India [closed]

I am working on developing a Slope map of India (for my research), where I collected DEM from Bhuvan and tried to mosaic and then perform terrain analysis. But I am unable get the output since the ...
5
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2answers
164 views

Is there a difference between the Planchon & Darboux and Wang and Liu depression filling algorithms? Other than speed?

Can anyone tell me, based on actual analytical experience, if there is a difference between these two depression filling algorithms, other than the speed at which they process and fill depressions ...
4
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1answer
98 views

In which way is height information stored in a DEM?

I'm struggling with different DEM data, because I don't know how to convert the height information in meters. When I load ASTER and SRTM tifs in QGIS, it shows me the spectrum of the grayband (0 to ...
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0answers
37 views

Question about projected coordinate systems 30m DEM for Contiguous US

What is the best Projected Coordinate System (PCS) for the contiguous US (whole, not parts) if I want to maintain distance and area accuracy as much as possible across a nationwide DEM dataset? I'm ...
0
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0answers
38 views

QGIS DEM Output cell size does not match DEM input cell size

As my first post I offer a humble apology if this is such a basic question as to make any of you cringe. I feel like I have exhausted my search skills and read through the QGIS documentation ...
8
votes
1answer
432 views

How to generate a DEM from isolines and spot heights?

I have two shape files containing height information of a certain area and I need to create a raster DEM with GRASS using them. file 1 consists of height information in contours (isolines) file 2 ...
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0answers
31 views

Converting DEM data to height information in meters using QGIS? [duplicate]

I'm relatively new with QGIS and currently I'm working with ASTER and SRTM DEMs. The goal is to create vector heightcontours with labeling in meter. Can you tell me how I can convert the grayband ...
4
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0answers
122 views

Flow direction generated for river is incorrect

I am trying to generate a hydrologic model and I can not really proceed on the next processes. I have this problem on generating flow direction. I have already executed fill sinks and the next is flow ...
12
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4answers
2k views

Comparing two Digital Elevation Models (DEMs) from LAS files?

I have two Lidar las files, one is original let's say with X points. And the other is copy of the first las file but with Y points, where Y is less than X. Now, I want to compare how the Digital ...
2
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4answers
612 views

What could cause garbage hillshade output

I've used Hillshade successfully in the past, but for this DEM I keep getting a weird output. It's a 30-meter TIFF downloaded from the National Elevation Dataset. And this is what the output looks ...
9
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3answers
1k views

Create DEM from stereo pairs?

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 ...
3
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1answer
80 views

Very high resolution stereo-imagery

I'm looking for very high resolution stereo imagery to perform a DEM extraction. The only place I can find sample data is http://www.digitalglobe.com/product-samples but the form does not work for me. ...
0
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4answers
108 views

Using Arcpy, how can I determine min and max elevation from a raster DEM layer within my current extent?

Using Arcpy, how can I determine min and max elevation from a raster DEM layer within my current extent? I'm currently using Data Driven Pages to centre the layout on each feature extent. I need to ...
0
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2answers
95 views

r.topidx error: required parameter output not set

I'm calling GRASS r.topidx from QGIS 2.2.0. I can get other tools to work on the DTM, for example r.watershed. But r.topidx I get the Oops message: Oooops! The following output layers could not be ...
1
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1answer
247 views

How to handle “illegal data type (Float64)” error when trying to convert .tif to .bil?

Each time I try to convert (in QGIS 2.2) an elevation model from .tif to .bil format a get this error: ERROR 1: Attempt to create ESRI .hdr labelled dataset with an illegal data type (Float64). ...
2
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1answer
231 views

qgis2 slope analysis from NED data gives crazy histogram

I'm attempting a simple slope analysis in QGIS2 using the plugin at Raster -> Terrain Analysis -> Slope. The slope output layer has a very strange histogram, basically spikes at 0 and at 89.9098 with ...
4
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0answers
75 views

Has anyone used ArcGIS for 'automatically' detecting lineaments from a high-resolution (1m) DEM?

I have a set of DEM's produced from LIDAR data. I am wondering if anyone is familiar with or knew of any published research papers which looked at (semi-)automatically detecting lineaments /or ...
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0answers
12 views

Manipulating Interpolation Outputs

I would like to clip the edges of my interpolation output to cover only a specific Local Study Area and also combine the output with a DEM to create a spatially defined 3D model in ArcGIS 10.1. Two ...
8
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3answers
538 views

How to extract breaklines from a given DEM?

Breaklines are very useful for describing a terrain - for example to build an exact TIN. My question is, how to extract these breaklines from a given DEM? I calculated the curvature (vertical) - ...
7
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3answers
1k views

Generating TIN from DEM using MacOSX/Unix tools?

I'd like to generate a 3d terrain model moving from a DEM dataset (currently in shp and GeoTIFF format). As far as I understand it, the first step of the better path would be generating a TIN, but I ...
3
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1answer
75 views

How can I create a constant slope DEM?

I wanted to create a DEM of constant slope say 1/3000. How can I proceed in ArcGIS 9.3? The area may be 1000m x 1000m or any other as per convenience.
0
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0answers
52 views

How to generate GML by extracting heights from DEM?

I am trying to generate GML using satellite images for geometries of various objects, and I propose to use DEM of the corresponding area in order to extract heights. I already have a piece of ...
2
votes
1answer
132 views

Obtaining average value around polygon in raster for different cross sections?

I have elevation data in a raster, river (blue line) and the flooded area (black polygon) as shown in the image below: I want to find the water depth in the flooded area (inside the black polygon). ...
0
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0answers
127 views

DXF (points and lines) in QGIS - Doesnt import z coordinates

Trying to get to grips with QGIS, coming from a Mapinfo and Civil3D background. I have a DXF file with points (X,Y,Z) and lines. I want to open this in QGIS and use the interpolate plugin to create ...
1
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1answer
68 views

Extracting DEM from imagery using ArcGIS for Desktop?

I'm using ArcGIS for Desktop and I'd like to know how can I extract the elevation model from a imagery of photos. I have the have each image (jpg) geo referenced. After, I don't know what tool may use ...
0
votes
1answer
47 views

What dem data are Flex Viewers using to create elevation profiles?

I asked a similar question a year or two ago here: Can Elevation Profile data in Arc's Flex Viewer 3.0 be exported? which appears to not have an answer. Another question regarding the Flex Viewer ...
3
votes
1answer
93 views

Elevation maps from point clouds: TPS vs. what other methods

In the reply to another question, @thehealingprocess refers to "...a comparison of interpolation methods for interpolating elevation maps from LiDAR clouds, and in almost all scenarios thin ...
0
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1answer
47 views

Viewshed over Multiple DEM Models Possible?

I finally got the viewshed working correctly over one DEM model. However, I am wondering is it possible to do the viewshed over multiple DEMs? E.g. A Multiple County Viewshed based off one point. ...
1
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3answers
237 views

ArcMap - Making DEM using GPS vector data [closed]

I am new to GIS and GPS. I am going to make a digital elevation model of my school's campus using a trimble gps unit. I know the accuracy is not the best but it is just for a school project. My ...
4
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1answer
77 views

How can I get the profile graph on ArcMap to display specific points?

I currently have 2 layers: 1) DEM of existing terrain 2) Polygon in vector format of future water retention basin I need to draw cross sections across this basin for eventual cut and fill calcs. I ...
0
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1answer
569 views

QGIS 2.2: GDAL Grid (Interpolation) Error

As much as i understand Raster -> Analysis -> Raster (Interpolation) can provide me with a terrain file out of a shape file with a Z coordinate. I select the input and output file and a Z field. It ...
0
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0answers
71 views

How to create .dem file in QGIS?

I have an elevation data in .asc file, but need to convert it to .dem file to later use in COMSOL. However, in Raster--> Analyzes-->DEM I got just error message: ERROR 1: DEM Default Setup: Importing ...
1
vote
1answer
272 views

Dem file in .adf format, while .tiff is needed

I would like to use this standalone tool to get different kind of Dem visualizations (http://iaps.zrc-sazu.si/en/svf#v). I see that the program accept only .tiff DEM. Now, the DEMs I got are not in ...
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2answers
105 views

Retrieve Elevation from Color in Raster DEM

This might turn out to be a newbie question, and that would be because I'm fairly new to GIS work, but extensive online searching, asking associates with some basic GIS knowledge and hours in various ...
0
votes
1answer
100 views

Best Resampling Method for DEM reprojection in QGis

I need to reproject a DEM (aster file) in order to have the same CRS as all my other project data - I have different SHP for the same DEM's location but they have a different CRS. Which resampling ...
2
votes
1answer
314 views

Possible workflows for shaded relief representation as vector

I am looking for a good workflow on how to represent relief on a map as vector (e.g. for further processing in Adobe Illustrator or Inkscape). My inspiration is the present google maps at zoom level ...
8
votes
4answers
5k views

How to 'burn' a stream network into a DEM layer in ArcGIS 10?

I am working on a DEM that in an area where there is little relief. I would like to 'burn' the river network into the DEM so I can calculate flow accumulation and flow length accurately. I am using ...
3
votes
1answer
121 views

How to obtain a DTM/DEM from DSM

I need to obtain a grid of bare ground elevation (removing all edifices, trees, roads and man-made elements) for quantitative geomorphological analysis from a high resolution (1 m) DSM obtained by ...
4
votes
3answers
360 views

Las to bare-earth DEM: average points spacing and cell size

I am using ArcGIS 10.1 to generate a DEM (bare earth) from LAS dataset. To accomplish this, I use 'Las Dataset to Raster' tool as described in Esri website. I have read here and there in the web that ...
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vote
2answers
188 views

DEM mosaic: gaps

I have generated DEMs (bare earth) from Lidar data. For computational reasons, I have processed via ArcGis the lidar files in chunks, so I came up with different single DEMs. After, I used "Mosaic to ...
0
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0answers
54 views

Advice on how to present a cross section

So, I'll try to best explain what I want to do. I have a DEM of a volcano (only showing half the DEM in pictures below) and I have identified a lava flow that I would like to make a cross ...