The vertical distance of a point or object above or below a reference surface or datum (generally mean sea level).

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7
votes
5answers
5k 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 ...
7
votes
5answers
1k 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 ...
4
votes
3answers
741 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?
11
votes
3answers
926 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 ...
0
votes
0answers
594 views

buildings shadow areas calculation

is it possible to calculate shadow areas of buildings or simulate shadows of buildings in a city using e-cognition software, with the DSM of the buildings and the sun angle and azimuth known?....if ...
7
votes
2answers
813 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 ...
3
votes
6answers
2k 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?
0
votes
1answer
693 views

How to load National Elevation Data into a WMS server?

We have an application that can pull WMS data from the National Elevation Data set (NED) and use it to perform a number of run-time calculations. We have been pulling it from NASA JPL WMS servers ...
9
votes
4answers
3k 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 ...
1
vote
3answers
2k views

Where can I download 1 arc-second elevation data for Canada other than Geobase?

Can someone suggest a source for Canadian elevation data better or equivalent to 1 arc-second? I have a good data source for Ontario but for other provinces folks often recommend Geobase which claims ...
14
votes
4answers
4k 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.
1
vote
1answer
245 views

Converting GPS heights to AHD heights

I was wondering if there is a way to convert heights that are logged from a normal bluetooth GPS to AHD heights.
3
votes
1answer
152 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?
7
votes
7answers
862 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 ...