Digital Elevation Model (DEM), which could be a Digital Terrain Model (DTM) or a Digital Surface Model (DSM).
2
votes
2answers
44 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 ...
4
votes
1answer
76 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 ...
2
votes
1answer
48 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
34 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
4k 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
96 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 ...
0
votes
1answer
28 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 ...
3
votes
1answer
77 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 ...
1
vote
1answer
69 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
24 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
415 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 ...
0
votes
1answer
95 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 ...
1
vote
1answer
55 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
78 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 ...
2
votes
2answers
93 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 ...
6
votes
0answers
83 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
50 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 ...
0
votes
0answers
10 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 ...
3
votes
1answer
104 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
63 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
58 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
89 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 ...
4
votes
2answers
151 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?
0
votes
1answer
50 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
227 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
69 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
99 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 ...
9
votes
4answers
891 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 ...
2
votes
1answer
71 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 ...
0
votes
0answers
26 views
gdal_merge.py aligns incorrectly at the seam of two GeoTiffs
I am trying to merge four GeoTiffs from the National Elevation Dataset (EPSG: 4269) into a 2x2 DEM using gdal_merge.py. For some reason, when it merges the upper two NED rasters, gdal produces a seam ...
2
votes
3answers
147 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 ...
2
votes
1answer
109 views
Compare two Digital Elevation Model (DEM)
I would like to know what's the best method(s) to compare two DEMs without using any GUI soft like QGIS or ArcGIS.
I'd like to do it in Python or C++, with GDAL or other similar lib.
Does calculating ...
26
votes
7answers
16k 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 ...
1
vote
2answers
109 views
Using SRTM DEM files in ArcMap for shaded relief
I would like to create a nice shaded relief for France using SRTM3 data. Most of the threads on the subject are from awhile ago, when ArcMap was not able to import these without changing the file ...
3
votes
2answers
121 views
What is the best source 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 ...
6
votes
1answer
335 views
How do I find least cost path over a DEM based on slope magnitude and direction?
What sort of algorithms can I use to find a least cost path through a DEM where it costs more to traverse a cell going downhill or uphill than it does to follow the contour of the land?
All the ...
3
votes
2answers
140 views
how to fill voids in ASTER stereo-images for DEM generation?
I'm trying to use a stereo-pair of ASTER images to generate a DEM (in ERDAS Imagine). However, the mountains are rather cloudy and the images can't be used as they are. But the relevant parts (valley ...
5
votes
2answers
772 views
Can shaded relief be “blended” with DEM colour ramp in ArcGIS to produce a more visually dramatic result?
Not being able to use true transparencies with ArcGIS colour ramps where only solid colours are allowed has me always wondering about how to improve the look of the surface in my maps without ...
3
votes
1answer
209 views
Looking for Fortran code calculating drainage basin area
I am working in a project of glacier mass balance.
For my project I want to integrate the area of the drainage basin in a glaciological system model (GSM). As the drainage area changes with time due ...
5
votes
3answers
5k views
How to extract raster DEM elevations to vector attribute tables in ArcGIS 10?
I have an ArcMap 10 project with multiple layer groups. One layer is a raster DEM, another layer group is a bunch of vector shapefiles (including points, lines and polygons). The client wants all ...
1
vote
1answer
82 views
How to remove terracing from Civil3D GeoTIFF export?
I've received a GeoTIFF DEM that was exported from Civil3D and at every contour there is a distinct terrace created when I process an aspect or slope in QGIS with the GRASS plugins.
I've looked ...
6
votes
5answers
757 views
Is there an online tile-based elevation service?
I am working on an application that requires the elevation at a given lat/long coordinate for lots of closely spaced coordinates along any given irregular path. (The path is a trace of a ...
10
votes
4answers
362 views
Dikes extraction from DEM
I do have DEM of 1x1 meter and original LiDAR point cloud in .las, that DEM is made of. I need to extract river dikes (highest points of the dikes) to vector feature (point, polyline). Any idea for ...
11
votes
3answers
234 views
PostGIS interpolation / triangulation options
I'm looking for an open source workflow to automate DEM construction. We have a series of sites that fall within a LIDAR dataset. We want to create site specific DEM's for each site, and we're ...
3
votes
3answers
2k views
Global DEM to Slope calculation
I have downloaded SRTM GDEM (~90 km resolution). I am using ArcGIS 10. I have tried to use spatial analyst to compute for slope. However, I can not compute for the slope. The output values has only ...
0
votes
0answers
11 views
How to represent scale in legend after using '1-Band Raster Colour Table V1.x' for DEM
I was able to represent the DEM by one of the nice colour ramps with the 1-Band Raster Colour Table V1.x plug-in. How can I correctly represent this colour ramp in the legend, as it contains 255 ...
1
vote
1answer
62 views
How to apply DEM elevation adjustment parameters?
I have a nice DEM, created from UAV data, which I want to process further in QGIS, my platform of first choice. In order to represent the evelation of each pixel correctly, I have to adjust the ...
1
vote
2answers
79 views
What software is available on OSX for working with DEMs?
I have several adjacent DEM files and would like to combine them into a mosaic and then export to DEM and TXT. I know a Windows solution is to use MICRODEM but before installing Windows 7 I would like ...
1
vote
2answers
60 views
viewshed analysis for observers wearing visors?
I'm starting with a DEM, and looking to identify every point that can be directly "seen" from any point in a particular polygon on an overlaid layer defining an area on that DEM - like any other ...
