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
777 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
244 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
73 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
34 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
44 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
78 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
74 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
158 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
166 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
162 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
183 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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161 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
145 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
130 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
437 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
884 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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1answer
30 views

shapefile to gmt format

I have an ESRI shapefile of the contours of my study area, and I want to convert it into a format that is acceptable by GMT, so I can make an elevation map of my study area. Is that even possible? ...
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1answer
49 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
45 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
24 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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0answers
43 views

DTM Extraction/Smoothing in ArcGIS

I have an .las file, intended to be a DTM (bare earth) that I generated from a photogrammetry software package that has come out just a bit too lumpy. I now have the license for that software tied up ...
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2answers
195 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
74 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 ...
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1answer
61 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
119 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
92 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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308 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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57 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
207 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 ...
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0answers
57 views

Process to load elevation data into Oracle 11G

We have the National Elevation data set from USGS and considering loading it into Oracle (11G) database. Can someone help with the process/steps?
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81 views

How to find locations on a conditional search [closed]

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 ...
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0answers
242 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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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 ...
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1answer
36 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 ...
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1answer
49 views

DEM difference looks like a hillshade

I wanted to find the elevation difference between 2 DEMs. When I got the data, I had to georef one image and had to aggregated it too because their cell values do not match. I also tried to resample ...
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1answer
276 views

How to conditionnally assign a new value to pixels of a raster image?

Given a topographic GIS raster of one country crop.tif: Given a know pixel value such as elevation (z) is +73 : $ gdallocationinfo crop.tif 1 1 -valonly > 73 Given an elevation threshold n = 50 ...
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2answers
371 views

Why does only one of three elevation rasters display correctly?

I downloaded a selected sub-set of the USGS National Elevation Data (NED) using their online GUI. This download came in the form of three files. The names of the files are 61471006, 61471006_2, and ...
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1answer
690 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 ...
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1answer
38 views

What dem data are Flex Viewers using to create elevation profiles?

I asked a similar question a year or two ago here: Can Elevation Profile data in Arc's Flex Viewer 3.0 be exported? which appears to not have an answer. Another question regarding the Flex Viewer ...
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1answer
2k views

Calculate maximum and minimum elevation for a polygon layer from a DEM [duplicate]

I have a polygon layer and would like to know the min and max elevation within each polygon. My elevation layer is a digital elevation model. I'm not quite sure how to extract that information. I am ...
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4answers
67 views

Using Arcpy, how can I determine min and max elevation from a raster DEM layer within my current extent?

Using Arcpy, how can I determine min and max elevation from a raster DEM layer within my current extent? I'm currently using Data Driven Pages to centre the layout on each feature extent. I need to ...
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1answer
58 views

ArcGIS 10.2 Viewshed not using Z Value?

I'm currently trying to produce a line-of-sight map of a tower with no results. Every time I run the viewshed tool, the program uses the base Z value of the DEM. I use the DEM Raster for the ...
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1answer
62 views

Read Elevation from 1/3 Arc-Second NED .tif or .img

I'm trying to read multiple elevations from a USGS 1/3 arc-second IMG / GeoTIFF file. A sample of the files is available here (5 MB): http://tdds3.cr.usgs.gov/Ortho9/ned/ned_13/img/n43w108.zip I can ...
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1answer
51 views

ArcGIS10 Highest point via polygon features

I am using ArcGIS 10.0 with 3D Analyst, Spatial Analyst and Military Analyst. I feel like I am halfway to solving a problem but do not seem able to completely solve it. I have a polygon shapefile ...
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2answers
674 views

How to extract elevation data from binary .ADF elevation format at given coordinates?

I have a high resolution digital elevation model available. The ground resolution is 1 meter and the file format is adf which is some binary ESRI grid raster format. I have a script the outputs x/y- ...
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1answer
26 views

digital elevation model data help?

I know little about geographic data. I am trying to get a file of elevation data for the United Kingdom so that I can import it into a CAD program and convert it to an *.stl or *.dxf format. I ...
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0answers
30 views

“US NED” OnEarth JPL NASA Tiled WMS working?

I am working on developing a computer software application that displays a 3D terrain based on the 30m elevation data for USA. I am using the OnEarth JPL NASA Tiled WMS for fetching the elevation ...
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0answers
35 views

QGIS - Obtain elevation profile [duplicate]

I wish to obtain a bathymetry profile along the selected path (Google Earth calls this feature "elevation profile". Can QGIS 2.2 provide this? I created a layer using the WMS service to load the ...
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30 views

QGIS Bathymetry Display, Bathymetry along a path [duplicate]

This post has two related questions. I am new to QGIS or any GIS software so please forgive me if the answer is obvious. I wish to view the Bathymetry point for any given coordinates (e.g. as I move ...
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70 views

Problem with Elevation Profile Graph

I have a problem when creating the elevation profile using 3d Analyst. I have a DEM and a polyline representing a a highway route consisting of several line segments that I have manually combined. I ...