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

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2answers
69 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 ...
3
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1answer
633 views

How to convert to Australian Height Datum from Google Earth elevation?

I am trying to figure out how to convert from Google Earth elevation to Australian Height Datum (AHD). Google Earth's elevation / altitude is based on The vertical component (altitude) is measured ...
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0answers
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?
3
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1answer
464 views

How can I get the elevation of a point in openlayers?

I want to know if it is possible to obtain the elevation of a point with some type of control of others. I am painting a linestring with a series of coordinates but I need to know the elevation of ...
1
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1answer
103 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 ...
4
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2answers
402 views

Focal statistics to calculate saddle points from DEM

I have a conundrum with Focal Statistics and kernel files. I am been trying to identify saddle points in DEMs. I am attempting to rewrite this (thanks whuber) in a python script for 10.1. I have ...
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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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0answers
118 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 ...
0
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1answer
63 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.
5
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1answer
926 views

Labeling contour lines in ArcMap [duplicate]

Can anybody give me advice on how to label contours as shown in Figure 2 below? I would like to be able to put the label "on" the line, which is easy enough. But I'd also like for the contour line to ...
0
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1answer
253 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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0answers
290 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 ...
5
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3answers
291 views

Precision vs Resolution in elevation data

Update: A good example of my confusion: on the Wikipedia page for "digital terrain model" one can find the following statement about a satellite in the "See Also" section: TanDEM-X: generation of ...
5
votes
1answer
292 views

How to determine the most accurate elevation algorithm

I use an Android GPS cycling app to track my bike rides and I would like to get a reasonably accurate estimate of the total ascent I did on a ride. I understand that GPS is very inaccurate at ...
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0answers
56 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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2answers
653 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
186 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
162 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 ...
0
votes
1answer
107 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 ...
3
votes
3answers
1k views

Obtain all elevations points from a raster DEM

I need to obtain all elevation grid points from a raster DEM. I see the steps required as: Read in raster DEM (Arc Info Binary Grid format). Create subset area using Points2One (see triangle area ...
0
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0answers
493 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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1answer
159 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 ...
5
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1answer
1k views

Python Script for getting elevation difference between two points

I have several stream segments 1000 Km long. I need to find the elevation difference between two consecutive points of distance 1 Km starting from the upstream to downstream. How can I get the ...
5
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3answers
2k views

How to transform GPX-tracks into elevation-tracks with any GIS?

I have a GPS track in GPX format available from a recent bike tour and I need and want to do some analysis on the tracks. I'm wondering whether there is any way to transform the GPX data into an ...
3
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2answers
317 views

Add Surface Information in 3d-analyst

One of our guys is using the "Functional Surface->Add Surface Information" feature in 3D-analyst tool in ArcMap 10.1 to add elevation data to an XY list. It's the only feature we're using from the ...
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0answers
82 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 ...
1
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1answer
178 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 ...
4
votes
2answers
267 views

Huge x,y,z dataset into oracle, possible?

I have 200 .xyz files containing 1500000 points each. Is this possible to import this dataset to oracle? It makes a total of 300.000.000 points!!! Background is I want to improve a FME script that ...
4
votes
1answer
287 views

What functionality exists to calculate Cut and Fill for excavation?

Does qgis have the ability to compare and quantify existing versus proposed elevations?
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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 ...
0
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0answers
34 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, ...
2
votes
1answer
158 views

Making a subsurface TIN model

I had been very glad if any of you have time to help me. I am a student and currently writing a thesis. In this paper I will create a 3D model of a glacier, where I will show the internal structures ...
3
votes
1answer
81 views

What function should I use to assess the degree of elevational change (rocky cliffs etc.) of a DEM?

I have a DEM of my research area and I want to assess how the topography/elevation changes. I am specifically looking to see what areas may be good suitable bat-roosting habitat so I am trying to ...
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1answer
173 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 ...
2
votes
1answer
133 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 ...
0
votes
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 ...
7
votes
3answers
1k views

Elevation profile 10 km each side of a line

How can I get an elevation profile for a band of terrain? The highest elevation within 10 km (on each side of the defined line) should be taken into account. I hope my question is clear. Thank you ...
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1answer
159 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 ...
8
votes
1answer
348 views

How to generate a DEM from isolines and spot heights?

I have two shape files containing height information of a certain area and I need to create a raster DEM with GRASS using them. file 1 consists of height information in contours (isolines) file 2 ...
2
votes
1answer
373 views

Orthogonal Height Profile along line (sextante -> v.segment, r.profile?)

While trying to find a way to find "valleys/ridges" within a DEM, I'd like to know if there are tools, plugins or "methods" known or available to automatically generate height profiles along a given ...
1
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0answers
204 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 ...
4
votes
3answers
7k 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 ...
11
votes
1answer
411 views

Why does GPS altitude jump sometimes?

I am currently developing a little application in Android which uses GPS. When i click a button i start to record a "track". If i walk around i save my position every second into a file. This works ...
4
votes
1answer
643 views

Elevation graph from GPX file

I've got many GPX files in the following format: <?xml version="1.0" encoding="utf-8"?> <gpx xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" ...
5
votes
2answers
1k views

Exporting DEM-derived rasters to CSV from QGIS?

I have been able to import into QGIS a set of raster topographic maps and the associated DEM raster maps. It registered the two for me. From there I have calculated the associated slope raster map. ...
2
votes
1answer
145 views

Lidar Elevations Data

I am trying to acquire a method of detecting sub cm elevation without manually measuring from the field. Can LIDAR data produce this for me? Example: A 1500 foot long pipe conveying water from one ...
1
vote
1answer
142 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 ...
3
votes
1answer
581 views

How to get elevation with LibGeoTiff?

I'm trying to get an elevation profile from a geotif file ( downloaded from http://srtm.csi.cgiar.org/). I downloaded the libgeotiff library but i can's see any function that can return an elevation ...
4
votes
2answers
449 views

How to manually edit 16 bit GDEM elevation data on a Geotiff file

I'm building a virtual 3D terrain scenery using both satellite imagery (google maps satellite) and elevation data from GDEM Aster elevation data (geoTIFF format files). My problem is that the ...