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

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250 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 ...
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2answers
2k views

Reading National Elevation Dataset (ArcGrid/GridFloat/IMG) with python only tools

I've found high precision elevation (1/3 - 1/9 arcsecond resolution) data from the National Elevation Dataset provided by the USGS. It comes int IMG, Arcgrid, and GridFloat formats. I know ArcGrid ...
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1answer
644 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 ...
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1answer
166 views

How to extract elevation information from contour lines?

I'm working with OS windows 7 and using ArcGIS 10.2 and I have a point shape, which I must extract elevation for every point in it but the only useful data is a contour line shape. Not sure if it's ...
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3answers
112 views

Is there demand for a higher resolution alternative to GPS tracking in the GIS market?

If there was an alternative to GPS that provided higher resolution tracking, what applications would there be for it in GIS? Note that this means higher resolution, but not necessarily higher ...
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1answer
312 views

Buffer analysis - use of surface area based on DEM

I have one problem and this is that I would like to create a buffer around point. This is simple with ArcMap using the buffer tool. But is it possible to create the buffer considering also the true ...
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1answer
192 views

How to apply DEM elevation adjustment parameters?

I have a nice DEM, created from UAV data, which I want to process further in QGIS, my platform of first choice. In order to represent the evelation of each pixel correctly, I have to adjust the ...
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2answers
2k views

extract elevation values along a line using Google Elevation API

I note that there is the Google Elevation API. I see they have an example at the bottom showing an elevation profile for a line. Is there a premade service someone has put up on a website for me to ...
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1answer
465 views

Using SRTM data, how to get the coordinates of the peaks visible from a location?

Using SRTM data and a coordinate-altitude database of the peaks, I want to get the coordinates of the visible peaks from my location. I want to make an application similar to this. How is this ...
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2answers
711 views

Calculating slope over distance from raster

I am sitting with an elevation raster, trying to produce a calculation for slope angle. I have a cell size of 2,-2 and I am trying to figure out how to calculate cell value difference between adjacent ...
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1answer
96 views

Read height data from Meridian 2

I'm having difficulties reading the Gridded height data (OS Meridian 2). I'm loading with OSGB 1936 reference system but have trouble finding the lat/lon data for each point. i.e.I open the attribute ...
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2answers
698 views

Mosaicing LIDAR files in ArcGIS 10

I have a number of LIDAR files (the extension is .adf). When put together, they show the same area (each shows one part of it), so, before I do anything else with them, I would like to combine them ...
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2answers
33 views

Interpolate dxf polyline vertex elevation from DTM?

I am working on several autocad polylines (with several vertices...) that have the exact N,E coords but now I would like to add the elevation data for every polyline's vertices from a dtm. I thought ...
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2answers
32 views

Is convention to denote Building Elevation with respect to ground or sea level?

Have a query on shapefile. I have a shapefile containing a number of polygon features representing buildings. I am trying to extract the elevation of the building. I would like to know if the usual ...
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1answer
735 views

How to Create Cost Surface Raster for Least Cost Path Analysis?

I have a DEM raster and would like to carry out a cost path analysis. Among other factors such as slope, proximity rivers etc. I would also like to take elevation into consideration. According to ...
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2answers
76 views

How to determine elevation of points in shapefile from second shape file using ArcGIS for Desktop?

I am a bit new to arcgis and have run into a snag. I have a series of points in a shapefile that only have x and y coordinates. Additionally I have a series of other points in a separate shapefile ...
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1answer
123 views

How to calculate elevation differences between points and terrain model?

I have a points layer with a Z (elevation) field and a terrain model (points layer or polygons layer -triangles- or eventually raster). I'm looking for a way to select the entities of my points layer ...
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2answers
200 views

How to intersect shape files with elevation models?

I have a high resolution digital elevation model (DEM) and a line shape file displaying a bycicle track. The DEM has 1 meter resolution. The line shape is something like 25 km long. What I need is a ...
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1answer
423 views

How to calculate an hypsographic curve of a raster trhough a DEM

I am using Arcgis 10.1. I have a MODIS raster from the NSIDC website with a pixel resolution of 500 m and an attribute table with the fields 'VALUE' (as the code of snow, clouds, etc.) and 'COUNT' (as ...
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1answer
822 views

Why does QGIS Profile from Line tool give me the same value for every point?

I'm trying to make an elevation profile with QGIS's Profile from Line plugin. But when I do, the resulting points all have the same value: -32,767. I'd like to know what I'm doing wrong. My elevation ...
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1answer
248 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.
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2answers
114 views

Creating a DEM from CAD contour polylines

Is it at all possible generate a digital elevation model raster from CAD contour polylines with elevations? I am using straight AutoCAD 2014, not Map3D or Civil3D. I was able to bring the dxf of ...
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1answer
44 views

Combining several rasters before r.surf.contour?

I have been trying to generate an elevation model from contour lines using first v.to.rast.attr and then r.surf.contour. Generally, it works pretty well, execpt for one issue. My data contains a lot ...
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1answer
49 views

Make a Ground Mask raster with the Greater Than tool (DEMs are generated from LiDAR)

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 ...
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1answer
97 views

Find minimum elevation along a polyline and return xy or point?

Using ArcGIS 10.1 and Python IDLE 2.7.2... I'm trying to find the minimum value of a polyline with a raster layer and turn that LOCATION into a point. I put everything together in model builder, but ...
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1answer
88 views

difference of reference plane/Plane Height / Z factor in Surface volume calculation?

I have a TIN surface with Minimum elevation 25 m and Maximum elevation 140 m. I want to calculate surface volume in different elevation between 25 and 140 meter. I wonder for example If I want to ...
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1answer
197 views

How can I make a reference plane to measure surface volume?

I am looking to make a reference plane like the links below. I want to measure surface volume of an area in different elevation layer. I just need to know how to make the reference plane in ArcGIS ...
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1answer
194 views

3D and 2D lengths of lines in ArcGIS

I have a 2D road segment and convert it into 3D using a raster in ARCGIS 9.3. So, what i see is that the length of 3D road segment is still the same as the 2D road. How can this be? As due to ...
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1answer
173 views

Python GDAL: find out spikes and pits in DEM

I'm working with on a DEM (Geotiff) in Python GDAL, and I'd like to find out the spikes or pits in my terrain. I have no idea how to proceed, does anyone have good algorithm to help me out? Thanks, eo ...
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1answer
205 views

Which horizontal unit is used on the table of the Profile Tool?

Does anyone knows what horizontal unit is used on the table of the "Profile Tool". Vertical is in meter but I don't know about the horizontal axis. Knowing the length of my profile, I tried to divide ...
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1answer
163 views

calculating terrain elevation line

I found too many hits on the web to even see the right direction to go. I have to provide a small proxy server serving requests for a line of terrain elevation data between two coordinates. It is a ...
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1answer
148 views

How to correlate raster map and elevation data?

I have been provided with a set of raster maps. Thanks to another helpful user here I have been able to acquire some elevation data for the same region from gis.utah.gov in asc format. Now I need to ...
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1answer
133 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 ...
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1answer
465 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 ...
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2answers
928 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, ...
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0answers
15 views

QGIS Extract elevation data only for one country [duplicate]

Hye, Here a map built with (1) a shape file for country contour, and (2) raster from .hgt files with altitudinal representation. How can I only select the area corresponding to the country ? I found ...
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0answers
32 views

River flow downhill

I have polylines (rivers) with assigned elevations. I need to ensure they are flowing downstream and indicate which vertices are incorrect. I do not have 3D analyst, spatial analyst, or network ...
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1answer
31 views

Select points with lowest elevations and same x,y coordinates

The problem is as following, I have a point layer with x,y,z coordinates. Some of the points have same x,y but different z. I need to separate points without duplicates (x,y) and in case there are ...
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0answers
44 views

Inverting color ramp in legend

I have inverted the color ramp to display land surface elevation, now when I add a legend in print composer it shows the lowest value at the top and the highest at the bottom. See below: It is more ...
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0answers
19 views

How to merge elevation from a raster image onto a shape road network with QGIS? [duplicate]

I have a shape file with Stockholms road network and a raster image with elevation data from the same area. Is there any way to merge the two somehow, either by adding the slope direction as ...
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1answer
108 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 ...
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0answers
71 views

SRTM elevation data question

I have a question concerning the SRTM elevation data (http://srtm.usgs.gov/). As a little thought experiment, assume I want to build a 3D model of the earth's surface as a point cloud. The earth's ...
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1answer
41 views

Adding shapefile elevation data to dted

I am a newbie to QGIS. Currently trying to augment a dted raster value file with vector shapefile(polygon) containing height of buildings. Have converted the shapefile into raster via rasterize ...
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2answers
300 views

How do you convert SRTM HGT elevations from WGS84 into meters above sea level?

I am building a JavaScript script that reads binary HGT files - as generated by the SRTM - and converts the data into bitmaps viewable in your browser. You can try out the script and view the source ...
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1answer
67 views

arcGIS observer point analysis: Exceeding maximum allowed points amount not exceeded

I need to make an observer points analysis (3D analyst tool). I have a shapefile of 22 points, so I divided it in 2 layers of 11 each as the maximum points allowed is 16. However, as I launch the ...
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0answers
134 views

How to create a buffer around a point that takes terrain elevation in account?

In QGIS, I am creating a few different buffer around points to simulate walking distances. For example, 10 minutes walk about 800m at 5km/h. Using population density, I then clip a population layer ...
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0answers
96 views

Unsplit lines based on length and attributes

I have a contour dilemma. Using Microstation, 1-ft contours have been made on a til-by-tile basis in our project. These DGNs were imported into a GDB, so the polylines have already been merged ...
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367 views

Topography: How to convert raster into vector layers?

(nb:This project is part of the #Wikipedia #wikimaps project) 1. Question: How to create vector topographic maps from raster image ? How to convert raster topographic image into closed vector ...
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0answers
60 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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0answers
218 views

Can Elevation Profile data in Arc's Flex Viewer 3.0 be exported?

a related thread here: google earth profile used in mashup or flex Would like to export the elevation profile data (csv, txt, etc.) from Arc's Flex Viewer 3.0 as it creates one: Also, if there is a ...