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

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1answer
34 views

Is it better to take the elevation of a GPS unit or that of a Digital Elevation Model?

When searching of gps routes in wikiloc, for the trailrunning race "Transvulcania" I have several routes to look. I downloaded a lot, but every route has a distance between 71 kilometers and 74 ...
0
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1answer
23 views

Generating elevation 'database' from NED IMG data

I'm starting to work with the NED 1/3 and 1/9 arc-second data. I've been using gdal in Python and QGIS to do some basic conversions of the raw .IMG data from USGS. My goal is to get elevation data of ...
0
votes
1answer
23 views

How to input Shapefile point data into a raster and have the raster adjust to the new data?

I have a shapefile with elevation data at specific points. I also have a raster that has incorrect elevation values, but the transition between pixals is what I need. Is there a way to put the values ...
1
vote
1answer
415 views

Using GDAL to read dted files

How do I get the elevation at a certain point using gdal to read in a dted file? I don't see much useful information out on the web. I'm sorry I should have been more specific. How would I ...
-1
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1answer
20 views

ArcGIS elevation? [duplicate]

I would like to get the elevation of different point in the digital elevation model means around 4000 points would any one please tell me how can it be possible.
9
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2answers
979 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 ...
1
vote
1answer
776 views

How do I add elevation data to a GeoJSON line from a GPX file?

I understand that elevation can be added as an optional third value in Coordinates (lat, long, elev) in a geojson file, but I can't find a way to actually do that from a gpx file. I've used ogr2ogr to ...
0
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0answers
34 views

Using Raster Calculator with Elevation Data from Contour Map

I am following this tutorial to attempt to determine flooding in the Gulf region based on estimated rises in sea level. I have taken topographic maps from the USGS and used to contouring tool to turn ...
2
votes
1answer
158 views

Computing the elevation angle of a GPS satellite with respect to the given receiver location

can anyone source an explicit formula for calculating the elevation angle for a GPS satellite as seen from a receiver. I can't seem to find one. Even a text reference would be great. I couldn't quite ...
3
votes
1answer
166 views

How to map flood areas from a set of points containing surface and height of water?

I am working on the damages made by the typhoon Haiyan. I use QGIS 2.0 with extensions and toolbox, and MapInfo. I have vectors, rasters of the place. I want to map the flood area along the ...
16
votes
3answers
6k 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 ...
0
votes
2answers
100 views

Seeking web service that returns elevation profile between two points and can process 5000 requests per second

I need a web service that provides elevation profile data between two coordinates with request rates at a minimum of 2000 requests per second but preferably at 5000 per second. The distance between ...
4
votes
6answers
3k views

shadow simulation from buildings [duplicate]

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
2answers
83 views

Kriging values greater than the most extreme value of the input layer?

I'll admit I don't understand kriging to the fullest. Yet, I've read that the weights should add up to 1 as in IDW and Natural Neighbors. However, surrounding the biggest elevation points of my ...
1
vote
0answers
18 views

QGIS Extract elevation data only for one country [duplicate]

I have a map built with a shapefile for country contours and a raster from .hgt files with elevation representation. How can I only select the area corresponding to the country? I found some thing ...
2
votes
1answer
282 views

Extract elevation data from Landsat / MODIS imagery?

Just curious, have anyone tried to extract elevation data from LANDSAT or MODIS imagery? So far, I came across one journal by Toutin who did so using adjacent LANDSAT 7 imageries. Results seem pretty ...
5
votes
3answers
1k views

What's the difference between hypsography and topography?

I've recently come across some data that has been labeled "hypsography". I looked it up and it sounds like topography. But this data source has data labeled "topography" separate from its ...
7
votes
3answers
502 views

Precision vs Resolution in elevation data

Update: A good example of something I am confused about: on the Wikipedia page for "digital terrain model" one can find the following statement about a satellite in the "See Also" section: ...
1
vote
0answers
40 views

How to get the elevation of the complete sea floor?

I am not a cartographer, I am an analyst-programmer, I know nothing about SRTM, DXF, PostGIS, QGIS... I just saw those names in other questions... Is there a quick guide where I can learn about this? ...
4
votes
2answers
1k views

How to create contour lines from point data using QGIS?

I'm using QGIS 2.4.0 and I have a shapefile of points with elevation data and X and Y coordinates. I'm using windows 7 OS. The idea is to create a contour line SHP using my point data. My question ...
1
vote
0answers
33 views

Modifying DEM elevation data in QGIS using a polygon

I've tried searching through the existing questions but am struggling to find a succinct answer to what I am trying to achieve. For background, I am running a flood model in TUFLOW to help support a ...
4
votes
5answers
1k 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 ...
0
votes
0answers
35 views

Extract value from Raster data by elevation

I have one raster data (AVHRR NDVI value) and one dtm data (elevation value). Is there anyway to know the NDVI value by 50m interval elevation? For example, I wanna know what is the NDVI value for ...
1
vote
0answers
44 views

Trajectory / ballistics

I'm trying to calculate if a canon will be able to shoot over a height in the terrain. lets saytThe canon have to be 15'000-18'000m from the target, and the impact degrees have to be over 30 ...
1
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0answers
33 views

Where can I obtain data on flood sites, land sewage systems, and property value?

I am a college student trying to obtain this data for a class project. If anyone can help that would be great. Basically, my hypothesis for this project is that land sewage systems that have not been ...
2
votes
2answers
44 views

find elevation for series of (lat,lon) combinations to make 3d model of earth with relief

I would like to say I am a complete novice to the world of GIS, so if I ask stupid questions or make strange assumptions, please point it out and I will try to clarify myself. I would like to make a ...
11
votes
5answers
7k views

How to calculate Topographic Ruggedness Index in ArcGIS Desktop?

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 ...
0
votes
1answer
48 views

How do I take a contour .shp file and create a separate layer for each elevation?

The end result is to have a .dxf file in which each different elevation resides in a different layer. If at all possible I would like to be able to do the organizing in tile mill, or through some ...
1
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0answers
26 views

cutting contour lines over raster (building) areas

I am looking to cut the contours in ArcMap and /or AutoCAD so they don't pass through buildings or roads. Is there a process or code to do this, so it doesn't have to be done manually? Also, looking ...
1
vote
2answers
74 views

Where do I get Elevation Data for Scotland?

So I am new here and I arrived here because I have been searching for quality elevation data for the entire Scotland but I have not succeeded yet. Kindly help if you know where to get the data Raster ...
2
votes
3answers
163 views

How to update the Z value using an UpdateCursor?

I have created the following script to mimic the ArcGIS 3D Analyst tool, FeatureTo3DByAttribute, which creates a 3D copy of a 2D feature class and sets the Z to a specified attribute. import arcpy, ...
0
votes
0answers
48 views

How to get elevation of a coordinate given a dtm file out of a PostGIS?

What would be the best way to get elevation of a coordinate out of a PostGIS database (SQL/plpgsql) given a GeoTIFF dtm file? Importing as PostGIS Raster (which seems more costly) and calling ...
0
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0answers
101 views

Converting from WGS84 Ellipsoidal Height to NAVD88 Orthometric Height

Is anyone aware of a way to batch convert or project elevation z-values from a point from WGS Height Above Ellipsoid (standard GPS height) to ortometric NAVD height using the GEOID03 model in ...
0
votes
0answers
21 views

What is the best option for web elevation profile using in-house DEM?

ArcGIS Server requires the advanced license for the 3D analysts extension. Are there any open source options? Thanks
2
votes
1answer
74 views

Make a ground mask raster with the Greater Than tool

I'm trying to see if I can replicate the Esri solar suitability site example from this article. I fail on the creation of the binary ground raster. I have made a Bare Earth raster from LiDAR ground ...
1
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0answers
90 views

Generate elevation profile graphs for multiple line segments in shapefile?

I'm familiar with the profile graph feature in 3D analyst and I saw the stack profile tool as well. However, I'd like to generate elevation profile graphs for 137 line segments. I don't want to ...
16
votes
4answers
347 views

How is elevation and altitude measured?

According to my watch that claims to measure altitude, as far as I can see it says that in Stockholm Sweden the altitude is 170 meters but can that be right? How exactly can we know that 0 altitude in ...
2
votes
0answers
74 views

Generate contour lines for big DEMs and import into PostGis

I've downloaded the SRTM DEM files for most of Europe, from both 3arc_v4.1 and 1arc_v3 versions. The first comes in 5x5 degrees tiles, the latter in 1x1. I can stitch them together with gdalbuildvrt ...
1
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0answers
47 views

How to show elevation on mouse hover in QGIS?

I've got a DEM layer and would like to have the status panel in the bottom display the elevation in addition to the mouse coordinate. Can that be done? Using QGIS 2.6.1
1
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0answers
42 views

How to calculate the Vertical Distance to Channel Network in ArcGis?

In Saga there is the tool "Vertical Distance to Channel Network". Is there a way to produce the same data in ArcGIs? With con("flowacc" > xx, 1) I was able to create the Channel Network. I am ...
9
votes
4answers
12k 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 ...
1
vote
1answer
75 views

Displaying DEM with real elevation values in ArcGIS Desktop?

I am trying to create a DEM with hillshading map in ArcGIS Desktop 10, but I'm getting the result with scale values between 0 and 254. How can I display the scale with the real elevation values? ...
1
vote
1answer
74 views

Changing the Axis on a Profile Graph

I'm working on a map with forest trails and I want to get an elevation profile of them all individually. I have gone through and interpolated the trail layer with a DEM so that I can use the 3D ...
0
votes
2answers
69 views

Calculate mean elevation over a region

For the purposes of spatial interpolation, I have created a grid using "Create Fishnet" in ArcMap10.2 (I use the "label points", which have a spacing of 0,00833333 degrees). For every point (label ...
0
votes
1answer
91 views

How to obtain elevation value from given SRTM data on mouse click in web browser?

I need JavaScript code for obtaining elevation data from SRTM tiff image. I have used Google APIs, but I need for downloaded SRTM tiff image. (SRTM file is being loaded on a base layer, and both ...
2
votes
1answer
174 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 ...
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votes
1answer
43 views

How to decrease elevation values of DEM using open source GIS sotware? [closed]

I am newbie in QGIS, but I was wondering how to decrease elevation dem DEM using QGIS? Can QGIS do that? Or anyone of you can tell me any open source GIS software to perform that?
3
votes
1answer
1k views

What is the highest obtainable resolution of FREE elevation data in the UK?

I am seeking closure with this question guys. I am aware of various sources of free elevation data ~30+ m, and I have been searching for higher resolution FREE data for a while now. This already ...
0
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0answers
29 views

Where can I download 1/9 arc-second elevation data for the Hawaiian islands?

In same spirit as this question, I'd like to know where I can find 1/9 arc-second elevation data for the Hawaiian islands. The USGS national viewer provides 1/9 arc-second data for certain places, ...
1
vote
3answers
3k views

Downloading 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 ...