The vertical distance of a point or object above or below a reference surface or datum (generally mean sea level).
1
vote
0answers
62 views
How to find locations on a conditional search
Hope you can help
I have a set of points evenly distributed to 500m intervals, and stored elevation.
I want to find from a given location any other point with the lowest elevation within a 1,000m ...
1
vote
1answer
99 views
ESRI ISurface.GetElevation is extremely slow compared to GlobalMapper
I'm using ISurface.GetElevation on a Raster to get the elevation for a specific lat/lon.
I have to do this for a huge set of datapoints.
Currently i'm testing with a dataset of 10.000 items which ...
1
vote
0answers
237 views
How to create a profile with profile points at discrete altitude intervalls, e.g. each 10 m
In both SAGA and QGIS theres a profile-from-line-function that does a nice job of creating profiles. But there's no way to control the altitude spacing.
Any ideas for workflows that would allow me ...
1
vote
0answers
180 views
Read negative elevation data from NASA png tiles
I query NASA JPL service using query string. Response is a unsigned 16 bit per pixel png image and the values are elevation values in meters. Same is described in the capabilty xml of the layer as can ...
1
vote
2answers
546 views
How to get the altitude of the vector shapes from DTM raster layer?
I have a vector layer containing thousands of vector shapes/polygons and a raster layer with DTM. Every shape has its own OBJECTID in attribute table. I would like to get the altitude of every shape, ...
2
votes
2answers
287 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 ...
3
votes
1answer
745 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.
...
1
vote
1answer
397 views
Help with technique to create contours from ASTER DEM in Phnom Penh, Cambodia
I have the ASTER version 2 DEM of Cambodia. I want to use it to create 1m contours of Phnom Penh, Cambodia. If anyone has this already please let me know. Now, onto the problems:
I am using ArcGIS ...
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 ...
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 ...
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 ...
2
votes
1answer
469 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 ...
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 ...
2
votes
1answer
380 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
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 ...
8
votes
2answers
438 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 ...
3
votes
1answer
430 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 ...
3
votes
3answers
249 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). ...
2
votes
2answers
338 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 ...
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 ...
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 ...
4
votes
3answers
540 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?
0
votes
0answers
538 views
How to select an area in a raster map that is compared with another raster map? (intersection of two raster maps) [closed]
I have
raster map A=elevation values and
raster map B=raster with colors (each color represents a polygon boundary. raster map B is created with the use of v.to.rast)
I want to select the part of ...
10
votes
3answers
554 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
484 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
607 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
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?
0
votes
1answer
554 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 ...
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 ...
1
vote
3answers
1k 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 ...
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.
1
vote
1answer
192 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
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?
7
votes
7answers
604 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 ...
