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

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13 views

How do we know the Altitude of a Geosynchronous Satellite is correct?

Geostationary Satellites are about 26,000 miles above the surface of the Earth, Altitude is calculated by measurements taken from Barometric readings of Mercury reacting to Atmospheric Pressure; but ...
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0answers
9 views

Finding download for open source high resolution digital elevation model? [on hold]

I am trying to create a figure for a paper with a ~9000 km^2 watershed and want as high of resolution as I can get my hands on. How do I find the highest resolution DEM download for a particular area? ...
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1answer
1k 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 ...
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2answers
186 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 ...
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0answers
40 views

How to show a 2.5D surface of raster above terrain layer in Cesium?

I'm developing an web application that will show surfaces of rasters and terrain. These rasters are on GeoTiff format. I learned from example cesium can show image overlays earth surface. The ...
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1answer
49 views

How to select lines affected by sea level rise?

I'm doing a part for my master's thesis where I'm trying to find out which sites located near the coasts of Sweden that will be affected by sea level rise. I got a DEM with height data and have to ...
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4answers
313 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 ...
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1answer
30 views

Creating an elevation profile along a KML road based on ASC files

I want to make the elevation profile of a road in KML. I've found this online tool but its does not gives accurate elevations. I already have .asc files of the whole area that includes the KML route ...
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1answer
229 views

Generate 3D elevation points grid from 3D contour lines!

I have a shape file with 3D contour lines. I want that based on this information to generate for all this area a 3D grid of points with certain distance from each-other like every 50cm. I use ...
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4answers
113 views

Google Earth Polygon surface area to follow the curvature of the earth model

Question: When drawing a polygon in Google Earth with latitude, longitude and elevation values at each node, how do you ensure that the surface area of the polygon also represents the desired ...
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1answer
246 views

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

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 ...
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0answers
28 views

Using ArcGIS Spatial Analyst for elevation?

I have many csv files of ~1000 points with elevation and x,y data. These points were manually recorded off of scanned images of the surveyor's drawings at an archaeological site. I have made each of ...
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0answers
44 views

Averaging elevation for fishnet points in ArcGIS for Desktop? [closed]

I have a problem with adding average elevations for fishnet points. First of all I surveyed an area boundary of 16km2 using total stations. I got nearly 800 points to finish the boundary in this ...
3
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1answer
33 views

How to find elevation highest and lowest for a state or city

I am trying to find out the highest and lowest elevation for these types of geographical areas: continent (lots of ways to get info) country (lots of ways to get info) state (for the US states no ...
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0answers
96 views

How to request elevation data from ERDAS Apollo?

I'm developing a custom application(Desktop based using uDig SDK) where user have a provision to select the line feature on map to view its elevation chart. So far I can do this using Google ...
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4answers
8k views

How to download the entire ASTER GDEMv2 dataset?

In October 2011, 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 ...
1
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1answer
136 views

QGIS - Level curves - Voronoi Polygons

I am facing a difficulty in QGIS (2.8.2): I have three layers: layer 1: layer with points layer 2: layer of level curves (contour lines) layer 3: layer of Voronoi polygons obtained from the points ...
2
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1answer
33 views

How to calculate mean elevation in a DEM between a specific interval?

I have a DEM with different elevations between 100 m & 3828 m. I just want to calculate mean elevation higher than 1500 m? Can I do that?
2
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1answer
29 views

contour lines/ basement contour extraction

My purpose: getting out area between elevation contours (like b/w 600m and 700m). The contours could either be elevation ones or the basement contours. I got elevation contours using spatial analyst ...
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0answers
35 views

How to create an elevation profile in google earth from a kml?

I have a KML file of a stream that I originally created as a line shapefile in ArcMap (one stream extracted from a larger watershed data set). I need to create an elevation profile of this stream. ...
3
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1answer
40 views

Reading 1/3 arcsecond DEM data using C++?

I am writing my own application to use and present elevation data. So far, I've been easily using the three arc second SRTM data presented in ArcInfo ASCII format. But now I'm looking to use the ...
3
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1answer
56 views

Calculating median elevation for local authority areas using OS Terrain 50

I haven't been able to find anything that could comprehensively help me with my problem. I want to calculate median elevation for UK local authority areas. So far I've taken the OS Terrain 50 data ...
0
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1answer
46 views

Get Elevation of XY points [duplicate]

I am working with ArcMap 10.3. I have imported DEM files. When I imported the files they had the extension of .DDF. I would now like to be able to take a list of XY coordinates and, for lack of a ...
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4answers
887 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: ...
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1answer
896 views

Using GDAL in python to read elevation at a point from 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 ...
2
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0answers
25 views

Does USGS 3DEP data use a hash or checksum?

I'm downloading some USGS 3DEP elevation data, e.g., the file at the following URL: https://www.sciencebase.gov/catalog/item/563afea8e4b0d6133fe7357b The "ID" of this file is given in both the URL ...
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0answers
21 views

Convert EGM96 gps elevation to WGS84 ellipsoid elevation.

I have GPS elevation data (300k points) in EGM96. These points are located on the East US coast. I realise i need to work out the difference between the EGM96 and WGS84 ellipsoid in this region to ...
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0answers
26 views

How to find roads with similar incline?

I have no prior GIS experience, so please bare with me. What I'm trying to do is find a road (or a portions of road) from one country that is similar to another road(or portion of a road) from a ...
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1answer
37 views

Obtain free DEM data of South China

Is there any free source of Digital elevation model of China with the resolution of 30 meters or better and vertical accuracy of +-5m. Something along those lines
2
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1answer
30 views
6
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3answers
5k 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 ...
23
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5answers
2k views
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3answers
39 views

I have many points (the points have elevation) I want to remove some points that are too close together

How I can select points in a buffer (just each buffer) and among them choose a point that having more elevation? (in ArcMap) (Each point can be in several buffer and as each buffer can have multiple ...
4
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1answer
136 views

Interpolate temperature data (shapefile) using R

The answer below solved my fist question, so I edit my question as follows: I have a shapefile given with the attributes lat, lon, elevation and temperature. So far I have a script that interpolates ...
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0answers
51 views

How to create buffers having regard to topography with QGIS

I want to create buffers of 25 kilometers around points in a point-shapefile with QGIS. My problem is that I don't need an air-line distance of 25 km around the points, but a "real distance" having ...
1
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1answer
30 views

How to add hypothetical values to a raster?

I have to create Non-Regulatory Products for a few FEMA regions. Right now I am working on the 'Increased Flooding Scenarios' where you add a hypothetical value to the existing Base Flood (1', 2', and ...
3
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3answers
134 views

Get rivers from a DEM raster

I am new to spatial analysis and even newer to hydrology. I have a 30arc DEM elevation raster and I was wondering if I can use it as an input to get the approximate presence of rivers in a ...
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0answers
53 views

Elevation profile of river in R

I would like to plot the elevation profile of a river (shapefile, single line) in R. How do I extract the elevation values (from a DEM .tif, for example) for the river line. I tried clipping but that ...
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1answer
55 views

Free Digital Elevation (Terrain) Model of Europe or Germany

Is there any free (or not expensive) source of Digital elevation model of Europe or Germany with the resolution of 10 meters or better and vertical accuracy of +-5m or better?
2
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1answer
862 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
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1answer
64 views

Download of very detailed DEM files for Portugal?

Operating system: Windows 10, 64 bit. QGIS Version: 2.13.3 which I installed via the QGIS.org website. I need contour lines for a small area in Portugal. I saw a guide posted here: ...
2
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0answers
29 views

QGIS estimate height of feature vertices from TIN

I have a TIN representing a digital terrain model, and another polygon layer representing features (e.g. building outlines) which is assumed to 'sit' on top of the DTM. How do I calculate the ...
0
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0answers
19 views

Elevation data from floating point DEM in ArcGIS for Desktop? [duplicate]

I have acquired a DEM from local municipality. It is a float point DEM, and the elevation of each pixel is represented as simply "pixel value". What would be the correct work flow to convert this to ...
5
votes
1answer
104 views

Which is better for measuring actual ground elevation, NED or SRTM?

I know that NED DEM layers are created using mainly Lidar point clouds and that the SRTM derives its data from shuttle-based radar. I have both of these loaded into QGIS and can see that over my study ...
1
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1answer
99 views

How do I assign elevation labels to a custom set of points in QGIS?

Im trying to create topographic surveys using georeferenced images from a drone and a DEM/orthomosaic which has been created using Photoscan. I've managed to create contours and label them with ...
2
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0answers
44 views

How to get the most accurate elevation reading for the ground floor of a building?

I am looking into a way to calculate the elevation of the ground floor of many buildings in a study area. My plan is to run the building centroids against an elevation grid to get an elevation ...
1
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0answers
29 views

I have a .adf file and want to select an elevation range [closed]

I'm super new to GIS. I downloaded a USGS 30m resolution map of a bay, and now I want to specify all areas that are between 0m and -30m elevation. I need to find where a defined area contains 0 and ...
1
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1answer
27 views

How do I extract elevation data from a DEM using points I have in a CSV?

So I have a CSV with a lot of fields. The first 3 fields are the ID, longitude, and latitude. I have already converted to decimal degrees, and said to display XY data. (Is there something else I need ...
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1answer
43 views

How do you identify cuttings / crevices from a DTM or DSM using ArcGIS?

I am trying to identify where cuttings and crevices exist by using a DTM or DSM. My ultimate aim is to find where roads and rail lines sit within a cutting i.e. the land either side of them is higher ...
2
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1answer
77 views

Setting elevation data for tie points in Pix4D

I am currently working in Pix4D and am trying to assign elevation data to my selected tie points. I have aerial images taken using a camera with GPS from an aircraft and am working with a fairly ...