Digital Elevation Model (DEM), which could be a Digital Terrain Model (DTM) or a Digital Surface Model (DSM).
4
votes
1answer
93 views
How to calculate the volume of several DEMs to obtain elevation and volume changes?
I am trying to calculate the volume of several DEMs in order to obtain elevation and volume changes. I have pixels of 1x1 each one associated to an elevation. I used several methods but non of them ...
0
votes
1answer
30 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- ...
0
votes
1answer
44 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 ...
1
vote
0answers
150 views
tools from Geospatial Modelling Environment in ArcMap model [closed]
How to extract raster DEM elevations to vector attribute tables in ArcGIS 10?
Can GME tools be used in model for publishing a tool on web? I want to use it in integration with other tools in ArcMap.
...
0
votes
1answer
33 views
Qgis nightly build - DEM error
I installed Qgis 1.8 several months ago. It's been working like a charm. Earlier today, I decided to check out the latest nightly build. Installed GDAL 1.10 (already had 1.9 installed) and SQLite ...
0
votes
2answers
46 views
How to create a point cloud from DEM?
Please forgive my ignorance if I am asking a totally irrelevant question, I am still a GIS newbie.
I looked in Google and found a lot of links as of how to convert point clouds to DEMs.
I am trying ...
1
vote
2answers
75 views
How to find upstream and downstream villages along a river
I have a DEM extract of river and village centroid. How do i create an attribute table that shows which village is upstream of other or downstream to another. Can someone guide me the correct tools in ...
0
votes
0answers
20 views
QGIS 1.8.0-Lisboa error message when converting DEM to Contours
I am trying to convert a small DEM (1 megabyte) into contours. When I go to - Extraction - Contour- and run it I get the following message:
"ERROR 1: CPLRealloc(): Out of memory allocating 416 ...
1
vote
1answer
49 views
Global DEM and country borders
I am trying to split up the world into 2 categories based on elevation (below 2000m and above 2000m) while still including a country identifier. So in the end, I would like to have 2 types of units ...
1
vote
1answer
71 views
Does NASA DEM contain objects?
Following an answer to my previous question I am planning to work with NASA ASTER GDEM global dataset. I am trying to download it according to instructions given here for a couple of days now.
...
1
vote
2answers
50 views
How to intersect shape files with elevation models?
I have a high resolution digital elevation model (DEM) and a line shape file displaying a bycicle track. The DEM has 1 meter resolution. The line shape is something like 25 km long.
What I need is a ...
0
votes
1answer
37 views
How to run a shortest path analysis for DEM-derived streams and pour points?
I have a .shp for streams and another for pour points. Those features were extracted from a DEM by using the Hydrology package from the Spatial Analyst Tools of ArcGIS 10.
I want to know the distance ...
29
votes
7answers
17k views
What is the difference between DEM, DSM and DTM?
I am listing some of the acronyms used in our work and had to stop to think about whether to list these together or separately. In some circles they are synonymous, in others they have distinct ...
6
votes
1answer
99 views
Automatic detection of breaklines with a 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) - ...
0
votes
1answer
43 views
Creating Digital Elevation Model (DEM) from Google Earth Image? [duplicate]
I am very new to GIS and given the task to create DEM's of agricultural area. I have studied the advantages of DEM in agriculture now i just want to know how i should start to develop the DEM's ? How ...
2
votes
1answer
35 views
Should only a “bare-earth” DEM be used when calculating CTI?
I have 50-meter DTM and 20-meter DSM data available to choose from to use for calculating a compound topographic index (CTI). While the 20-meter resolution is more attractive, logic tells me that when ...
2
votes
3answers
159 views
Advantage of Digital Elevation Model (DEM) in Agriculture?
I have given the task to create Digital Elevation Model (DEM)'s of an agricultural area. I am programmer with Computer Science background and very new to GIS can anyone explain what is advantage of ...
2
votes
2answers
89 views
A library/software to create DEM from a topographic map
In one of my projects I need to digitize video clips showing some natural landscape. Specifically I need to know distances between different areas and elevation levels.
I have a topographic map of ...
12
votes
1answer
186 views
Creating nanoscale DEM with GDAL
A bit of a strange question perhaps, but let me give you a breif explanation of the background before my actual questions:
Atomic force microscopy (AFM) is a method that, in short (and to my limited ...
1
vote
0answers
39 views
DEM data - Central Europe - noise in heights
I have downloaded DEM data from this page: http://www.viewfinderpanoramas.org/dem3.html. I have written simple program in C++ that takes "bricks" and build resulting height map.
Hovewer, I have ...
0
votes
1answer
18 views
Input data format and read multiple files into Grass 6.4.1
I am trying to read in multiple (hundreds, thousand) LiDAR ascii files into Grass.
They contain elevation data.
I think I have managed one, and I can make a map of elevations, using File, Import ...
0
votes
1answer
119 views
How to calculate surface area of highland region using DEM with ArcGIS (ArcEditor)?
Am shyaka from Rwanda.
I use GIS tools and have all required data to perform or calculate surface area from the polygons that have been given by GPS (Trimble) with ArcPad 8.
I originate from a high ...
0
votes
0answers
21 views
Manually edit cell value in DEM in Arcmap10?
Is there any chance that I could manually pick a group of cell in DEM, then edit the value of them in Arcmap 10?
I know about the Aris Grid Editor for Arcmap but it requires licence and it's too ...
0
votes
1answer
66 views
How to find locations for hydro power using raster analysis?
I have a stream network and DEM file both in raster format. I need to extract values from DEM to stream network. For the analysis in stream network after that, I need to find out the places for hydro ...
-1
votes
0answers
23 views
Trying to create contours from DEM; getting ERROR 1 [closed]
I'm trying to create contours with a 10 ft interval from a DEM, and I'm getting the following error: ERROR 1: CPL Realloc () = Out of memory allocating 416 bytes. I've tried this on a geotiff and ...
3
votes
2answers
103 views
Autocorrelated DEM with QGIS or Grass
I was wondering if there is a way to make an Autocorrelated DEM within QGIS or Grass. I am looking to do this with stereo aerial photography. I am able to do this with a number of COTS tools, but I ...
3
votes
3answers
115 views
Obtain all elevations points from a raster DEM
I need to obtain all elevation grid points from a raster DEM.
I see the steps required as:
Read in raster DEM (Arc Info Binary Grid format).
Create subset area using Points2One (see triangle area ...
9
votes
4answers
942 views
comparing two DEMs
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 wanted to compare how the Digital ...
4
votes
2answers
177 views
How to drape a simple jpeg image over dem of some area?
How can we drape a simple jpeg image which doesnot have any geo referencing information over the digital elevation model in order to visualize it in 3D in QGIS?
1
vote
2answers
103 views
Is it possible to colour areas between (vector) contours?
...without making it a DEM first?
Joshdoe seems to have done so ("Styled in QGis") here but doesn't say how.
Thanks!
2
votes
1answer
54 views
Digital Elevation Model Algorithms
Can anyone suggest best Suitable Algorithm for Digital Elevation Model Generation? Currently I am working on Literature survey of DEM creation so i need to show comparison of 3-4 Algorithmic Methods ...
0
votes
0answers
40 views
How can i calculate the width of the dam?
I am working with Reservoir design. Now I am facing problem to calculate the width of the dam. I need to calculate the width based on DEM and height of dam at various points using Python. I am working ...
5
votes
1answer
5k views
How to calculate an elevation profile for a polyline in arcgis 10 with spatial analyst/3D analyst?
My elevation data is a floating point tif. I have a road for which I need to calculate the elevation profile, but I can´t see the tools to do this.
Can I do this with ArcGIS?
yours,
Rob
3
votes
2answers
108 views
Hillshade for 30m NED at continental scale
I'm new to terrain analysis. I have a 30m NED DEM (.tif) for the conterminous US. I would like to generate a nice looking hillshade for the US, but it looks bad - as in pixelated and rough (See ...
1
vote
1answer
121 views
QGIS contour lines shapefile to DEM help
I want to create a DEM from depth contours (shapefile) in QGIS. I've been trying to work out how to do this based on this previous question, notably from this link from that page, however I'm stuck, ...
0
votes
0answers
39 views
catchment delineation
I am trying to use qgis to delineate between three sub-sub-catchments.
I have contour shape file of 20 meter height.
Sub-catchment is about 12 square kilometers area but consist of three ...
0
votes
0answers
13 views
can anybody explain how to create a wasp contour map in Q GIS? [duplicate]
can anybody explain how to create contour map,I need to export in .map format.
8
votes
2answers
441 views
Extract the area of a DEM above where 60% of the region lies?
I have a DEM of a mountainous region. I'd like to extract the areas of the DEM above which 60% of the total DEM area lies. So, essentially I'd like to extract the areas representing upper portions of ...
1
vote
1answer
78 views
No. of Bands in the input Raster
I have downloaded a 7.5 min DEM . Now while I am trying to mosaic them it gives me an error saying "Input and target dataset should have the same number of bands" . How can I figure out the number of ...
3
votes
1answer
83 views
ArcGIS Raster Symbology - Break contour at 0
In ArcGIS 10, how can I break raster symbology (stretched) at a particular value (i.e. 0). For example, I have a DEM representing both topography and bathymetry and I want a break at the 0 m contour ...
3
votes
2answers
122 views
Calculating Runoff / Streams using DEM in ArcGIS
I am just curious about the workflow that many of you use for runoff/stream analysis using a DEM and create a "water network" from the results in ArcGIS 10.1? I know the average rainfall for different ...
3
votes
1answer
137 views
Python Script for getting elevation difference between two points
I have several stream segments 1000 Km long. I need to find the elevation difference between two consecutive points of distance 1 Km starting from the upstream to downstream. How can I get the ...
2
votes
1answer
73 views
TMS or WMS source(s) for DEM data tiles?
I'm spinning my wheels trying to find an existing, free source for TMS or WMS elevation data that doesn't involve a long-winded clickabout or an emailed url. This question has a similar purpose, but ...
3
votes
0answers
65 views
Shapefile and DEM: check rivers behaviour
I'm working with shapefiles representing rivers (rivers.shp), and DEM for the terrain elevation (terrain.tif).
Basically, I want to check that my rivers (stored as polylines in my shapefile) behave ...
5
votes
3answers
123 views
How to transform GPX-tracks into elevation-tracks with any GIS?
I have a GPS track in GPX format available from a recent bike tour and I need and want to do some analysis on the tracks. I'm wondering whether there is any way to transform the GPX data into an ...
0
votes
1answer
65 views
min and max values are not correctly calculated for DEM
I'm working with DEM in QGIS and need to know the min and max values of my data.
In the Properties window, under the Metadata tab, the statistics section shows such values. However, I usually find ...
5
votes
2answers
249 views
Problem Visualizing 3D Terrain Model - USGS DEM
I recently downloaded a GeoTIFF 1 arc second from the USGS National Map Viewer. I added the raster to ArcScene and attempted to visualize the data in 3D. I set the Base Height to Floating on a ...
3
votes
1answer
75 views
Compute global DEM topographic indices and compromise projections
I would like to compute global topographic indices based on SRTM elevation data. These indices are computed along river/channel networks extracted from a DEM and are a functions of both local slope ...
1
vote
1answer
146 views
DEM to STL (3D Printer Format)
I have a DEM in ArcGIS 10.1 that I would like to get into STL format for a 3D printer. Does anyone know some software that will allow me to make this conversion?
I have to use the STL format because ...
2
votes
1answer
84 views
Watershed extraction using different DEM tiles
I would like to extract the watersheds for a particular area using QGIS. However, I only have Aster 30m DEMs to work with, each tile covering one degree square. The problem is that I need to use ...
