The vertical distance of a point or object above or below a reference surface or datum (generally mean sea level).
12
votes
5answers
2k views
How to get an elevation profile for a gps track?
I'd like to get a reasonably accurate elevation profile for a track recorded with a GPS (which often has very unreliable altitude data and occasionally none at all, depending on the model.)
Does ...
12
votes
4answers
2k views
What is the best colour-ramp to use for elevation?
This is maybe rather subjective as it concerns style, but I would like to have a few decent colour ramps for my DEM when it is layed over my hill-shading.
I have created the Swiss hillshade model as ...
11
votes
3answers
2k views
Where to download free elevation data for Europe?
Where can I find free elevation data for Europe? Please mention the available resolutions and terms of use when posting a source.
11
votes
1answer
267 views
Why does GPS altitude jump sometimes?
I am currently developing a little application in Android which uses GPS.
When i click a button i start to record a "track". If i walk around i save my position every second into a file. This works ...
10
votes
3answers
2k views
How to download the entire ASTER GDEMv2 dataset?
On October, NASA released the new ASTER GDEM global dataset (30m) and I have been wanting to get my hands on it. The only problem is that it takes forever to download and I do not feel like drawing ...
10
votes
3answers
559 views
Distribution of Human Population with Altitude
I recently found Joel E. Cohen and Christopher Small's work on hypsographic demography, i.e. the distribution of human population with altitude.
Does anyone know of any other research in this area? I ...
9
votes
3answers
402 views
What are common methods for converting raster digital elevation data to vector contours?
In researching this I have found many references to the opposite, creating elevation data from contours, but nothing regarding contour creation. Preferably, I am looking for open source solutions like ...
8
votes
4answers
2k views
Code to calculate elevation profile along line from a DEM
Given a DEM (Digital Elevation Model) say in and a line (x1,y1) --> (x2,y2) (paired coordinates (x,y)), how can one calculate the elevation profile or cross-section projected on that line ?
I am ...
8
votes
2answers
442 views
Elevation profile sample point algorithm
In generating an elevation profile, samples from the underlying raster must be taken. If the objective is to create a profile of maximum quality, how should the locations of sample points be ...
7
votes
7answers
608 views
seeking “Available Sky” implementations
I'm looking for implementations of an algorithm called "Available Sky". ArcGIS (Spatial Analyst or GRID) is preferred, but solutions in GDAL, SAGA GIS or others are perfectly acceptable.
The ...
7
votes
2answers
614 views
What is the smallest contour interval possible when derived from a DTM?
I am converting a 2m DTM to contours, and would like to have the smallest interval possible. Is there a theoretical limit, or even a rule of thumb for defining contour intervals based on the ...
7
votes
1answer
535 views
PostGIS - Calculate progressive distance between points on a GPX path
I am attempting to build an elevation profile using PostGIS-PostgreSQL only.
I have imported GPX data in my PostGis database, so now I have a table full of the GPS coordinates of the track and the ...
6
votes
2answers
409 views
Elevation profile 10 km each side of a line
How can I get an elevation profile for a band of terrain?
The highest elevation within 10 km (on each side of the defined line) should be taken into account.
I hope my question is clear.
Thank you ...
6
votes
5answers
762 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 ...
6
votes
3answers
760 views
Raster: How to get elevation at lat/long using python?
I was wondering if anyone has some experience in getting elevation data from a raster without using ArcGIS, but rather get the information as a python list or dict?
I get my XY data as a list of ...
5
votes
3answers
3k views
How to calculate Topographic Ruggedness Index in Arcgis?
Does anyone know how to calculate Topographic Ruggedness Index in Arcgis without access to command line arcinfo workstation?
"The topographic ruggedness index (TRI) is a measurement developed by ...
5
votes
3answers
97 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 ...
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
5
votes
1answer
160 views
Cartographic technique for detailing a 'Focus Area'
I'm working on updating a planning document. Whoever was in charge of cartography last time around used a great technique to identify and showcase focus areas (where to focus money and effort for ...
4
votes
5answers
459 views
Elevation correction ASTER GDEM2 (+10m)
My ASTER GDEM2 has a average elevation error of -10m for my area. (I testet it using 90 defferential GPS reference points and compared it with old Topo25, SRTM, and GoogleMaps).
I would like to ...
4
votes
3answers
541 views
How to get the elevation of the areas in a raster file from SRTM?
I have an SRTM elevation map. How do I get the elevation of each point in the map? I am using GRASS. Is there a GRASS script to do such?
4
votes
2answers
122 views
Huge x,y,z dataset into oracle, possible?
I have 200 .xyz files containing 1500000 points each. Is this possible to import this dataset to oracle?
It makes a total of 300.000.000 points!!!
Background is I want to improve a FME script that ...
4
votes
2answers
377 views
Converting Geocentric to Geodetic
I am only looking for a confirmation of what I believe to be true. If my explaination or conclusion is not accurate I would appreciate it if the reason can be explained to me.
Background ...
4
votes
2answers
205 views
How to manually edit 16 bit GDEM elevation data on a Geotiff file
I'm building a virtual 3D terrain scenery using both satellite imagery (google maps satellite) and elevation data from GDEM Aster elevation data (geoTIFF format files).
My problem is that the ...
4
votes
1answer
81 views
What functionality exists to calculate Cut and Fill for excavation?
Does qgis have the ability to compare and quantify existing versus proposed elevations?
4
votes
1answer
243 views
Elevation graph from GPX file
I've got many GPX files in the following format:
<?xml version="1.0" encoding="utf-8"?>
<gpx xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" ...
3
votes
6answers
1k views
shadow simulation from buildings
is it possible to use hillshade function in ArcMap to calculate shadow areas of buildings or simulate shadows of buildings, using DSM of the buildings and the sun angle and azimuth?
3
votes
3answers
251 views
What is Trinity High Water?
This question may be off topic, in which case I apologise.
I have a problem where water level is important and I have two water levels defined, Trinity High Water and Mean High Water springs (MHWS). ...
3
votes
1answer
107 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 ...
3
votes
1answer
750 views
How to read GeoTIFF using PHP?
My current pet project involves creating a web service that uses the CGIAR SRTM worldwide elevation data set. Each request to the service will query for elevation data from a small geographic area.
...
3
votes
2answers
63 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 ...
3
votes
2answers
308 views
Exporting DEM-derived rasters to CSV from QGIS?
I have been able to import into QGIS a set of raster topographic maps and the associated DEM raster maps. It registered the two for me. From there I have calculated the associated slope raster map. ...
3
votes
1answer
47 views
What function should I use to assess the degree of elevational change (rocky cliffs etc.) of a DEM?
I have a DEM of my research area and I want to assess how the topography/elevation changes. I am specifically looking to see what areas may be good suitable bat-roosting habitat so I am trying to ...
3
votes
1answer
137 views
Corpscon6 reliability
I've been blindly using Corpscon to convert from NGVD29 to NAVD88. Have any of you kind folks found issues with your outputs?
3
votes
1answer
207 views
How to get elevation with LibGeoTiff?
I'm trying to get an elevation profile from a geotif file ( downloaded from http://srtm.csi.cgiar.org/). I downloaded the libgeotiff library but i can's see any function that can return an elevation ...
3
votes
1answer
85 views
Help obtaining nodata information for ASTER datasets
Is there any way to determine what the nodata value should be, in a set of geotiff images that do not have the 42113 tiff tag ? I am trying to get elevation information, programatically in c++, and I ...
3
votes
1answer
134 views
Change ellipsoid reference for altitude in a DEM
I have DEM data stored as RGF93 (Lambert-93) for lat/lon and NGF-IGN69 for altitude. I'm trying to change the reference ellipsoid for the elevation data (ultimately to NTF, but WGS84 would be fine to ...
3
votes
0answers
134 views
Elevation statistics for a given Area
I am attempting to determine the best way to calculate the Minimum and Maximum elevation for a defined area.
The area is defined by an IPolygon
The elevation is defined as an ISurface
Possible ...
3
votes
1answer
432 views
How can I programmatically project the Z value of a z-aware feature point, using ArcObjects in .NET/C#?
I discovered the following code leaves the Z coordinate of featurePt untouched:
// if not WGS84 project it
if (!SpatialRefsEqual(featureSpatialRef, srWgs84))
{
// featurePt here is a Z-Aware ...
2
votes
3answers
1k views
How to extract elevation from .HGT file?
I want to asign a specific long/lat position on a map the elevation from SRTM3 data files, but have no idea how to find the specific value. So I want some example of how I can find in N50E14.hgt ...
2
votes
1answer
101 views
Lidar Elevations Data
I am trying to acquire a method of detecting sub cm elevation without manually measuring from the field. Can LIDAR data produce this for me? Example: A 1500 foot long pipe conveying water from one ...
2
votes
1answer
166 views
Orthogonal Height Profile along line (sextante -> v.segment, r.profile?)
While trying to find a way to find "valleys/ridges" within a DEM, I'd
like to know if there are tools, plugins or "methods" known or
available to automatically generate height profiles along a given
...
2
votes
1answer
155 views
How can I calculate elevation from relief?
I have an SDE Raster that displays relief, but I want to display elevation. How would I go about doing this? I would really appreciate any advice or direction on how to do this.
2
votes
2answers
289 views
How to read elevation data from WMS response?
I am trying to get elevation data from the tile received from USGS server.
I query the data using Image Format image/Png. When I read the data I get color values.
I need to know how to read the ...
2
votes
1answer
474 views
DTED/GeoTiff layer: Get elevation under mouse pointer
I have a simple desktop app with a map control. The map data that will be available to show will be either DTED files (Military Analyst's catalog / MADTEDLayer), or GeoTiffs (created by gdal). I want ...
2
votes
2answers
1k views
Can WMS be used to get a local copy of raster data?
I have tried reading up on WMS on wiki and other sources but haven't managed to get my head around a couple of points.
1) Using WMS is it possible to get a local copy of the raster data (say a tiff ...
2
votes
1answer
73 views
Making a subsurface TIN model
I had been very glad if any of you have time to help me.
I am a student and currently writing a thesis.
In this paper I will create a 3D model of a glacier, where I will show the internal structures ...
2
votes
1answer
89 views
filter / generalize elevation points on the basis of some conditions
I wanted to generalize many elevation points in a rectangular area (about 700 square km). I need to take about 3 points for square km. These points must satisfy some conditions:
One of these ...
2
votes
1answer
381 views
Read .DEM (USGS) FIles with C#
I have a huge number of .DEMs and have been investigating how to process them into something useful.
Does anyone know how, or even if it is possible to read coordinates and elevation data from ...
2
votes
2answers
340 views
Elevation Data not showing on Globe
Using ArcGLobe I'm attempting to display elevation data.
I'm using Digital Terrain Elevation Data (DTED) data and trying to load it in the following fashion.
IRasterLayer rasterLayer = new ...
