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

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46 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
48 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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93 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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78 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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237 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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46 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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170 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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54 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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79 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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219 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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39 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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177 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
341 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
638 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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2answers
892 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
1k 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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2answers
452 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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2answers
65 views

Extract ground elevation from a path of lat/lon

I have a set of Lat/Lon points and I'd like to know the actual ground elevation of these points. I have access to Global Mapper, Google Earth, AutoCAD Civil 3D. Could somebody suggest the bets way ...
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19 views

What information, Open Attribute table of stream segment shows?

I have delineated the watershed from DEM data. I have converted the stream segment(raster) to vector lines. In the attribute table of this vector lines, there are 3 columns, CAT, VALUE, LABEL, what ...
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33 views

How to paint area below certain elevation, using no coding and Google Maps, Google Earth, Bing

How can I show the area below a certain elevation, using Google Maps, Google Earth, Bing Maps or similar end-user application, and no coding? Thanks in advance
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35 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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19 views

Programmatically download NED, Landcover, etc. data from USGS [duplicate]

What are my current options for downloading geodata (NED, landcover, etc.) from the USGS programmatically?
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1answer
59 views

How do I determine the subsidence of land in Manila, Jakarta and Bangkok?

Can I set how these cities have lost elevation using digital elevation models? Is there a digital elevation model which data are updated? Or are there other methods? Thanks.
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90 views

Is there a public FTP server hosting the NED?

I'm having a ton of trouble getting the data I need from the USGS. I have taken a look at the 10m DEM quad index and know exactly which quads I need, but cannot find a source to download them from. ...
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1answer
94 views

How to select a subset of a DEM in ArcScene?

I'm using ArcGIS 10.0 and trying to open a digital elevation model in ArcScene. I'm working on a project and got the DEM data from official sources which is quite huge. The resolution of the DEM is 1 ...
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364 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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23 views

Which all columns should I add in postgresql table so that it stores elevation values and displays them in Geoserver?

I am using geoserver and postgresql. I imported raster (.tif) file to postgresql using raster2pgsql. The file thus imported creates a new table in postgresql. But when that file is previewed in ...
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72 views

(.NET) Get DTED Data (Elevation) Between Two Points

I want to get DTED data (elevation) between two points (on a line). Is there any built-in function for this purpose or I should implement it on my own? What I want is similar to Linear Line of Sight ...
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31 views

How to extract elevation data from DEM along a polyline [duplicate]

I've been trying to use qGIS to extract and save as an attribute the data elevation along a line, knowing that something similar is available in ArcGIS using the Spatial Analysis tool. So far, ...
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555 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 ...