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
18 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 ...
3
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1answer
35 views

How to give elevation information to a polygon feature class using existing TIN file ? (geological mapping)

I'm an ArcGIS 10.1 user. My issue: I have a printed form of a map which depicts geological bodies being surface rock occurence. Additionaly, there are elevation contour lines. I digitized the map by ...
1
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1answer
29 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 ...
2
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0answers
21 views

Global height data as polygons — Natural Earth doesn't have it?

I love the bathymetry data from Natural Earth. I've been looking for the last few days for the same basic data but for land. I'm trying to find general elevation shapefiles, as polygons. I don't need ...
1
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1answer
80 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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2answers
51 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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2answers
62 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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1answer
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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0answers
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 ...
2
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1answer
29 views

Wrong sorting of elevation classes QGIS

I'm a totally beginner with QGIS and maybe I have a very easy problem, but I can't help myself. I got an elevation shapefile with classes of elevations like that: 1-100m, 101-200m, ... When I try to ...
4
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2answers
195 views

how do you identify ridges on an elevation raster?

I was wondering whether anyone might be able to tell me in layman's terms how to extract or differentiate between ridges and hilltops from 10m elevation data using ArcGIS 10.1? Any advice would be ...
6
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5answers
274 views

Looking for (nearly) worldwide elevation data

I know the raw ASTER and SRTM datasets. Is there any error corrected version available? Or did anybody already combine the data? At least the ASTER data often misses tiles for costal regions (if there ...
3
votes
1answer
78 views

Get elevation along a road from DEM in QGIS

When I draw a track in Google Earth, for example along a road, I can right-click it to "Show elevation profile", and it displays a 2D plot of distance vs elevation. However, if I save the KML, the ...
8
votes
2answers
210 views

DEM Elevation Units

I'm fairly new to the GIS world, and have a quick question. I'm currently using 10.1. I do not know much about rasters, so does transforming a DEM from one projection to another automatically convert ...
2
votes
2answers
58 views

Elevation and point data

On arcmap 10.1, I have elevation data that is shown as contour lines (polylines) i also have point data showing the distribution on certain animals. I want to run some kind of statistical analysis to ...
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1answer
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 ...
0
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0answers
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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1answer
212 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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3answers
86 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 ...
3
votes
1answer
51 views

Elevation off Road in ArcGIS/Python

i'm using the Modelbuilder in ArcGIS 10.1 to calculate pixels depending on their slope and distance from the road. The third necessary task is to find out, if the pixel is upwards the road or ...
0
votes
0answers
34 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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1answer
46 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 ...
2
votes
1answer
50 views

How to change layer transparency without changing border lines?

I have a raster image of elevations. I have added a vector shapefile that contains local political divisions. I want to keep the elevation colors, but I want to keep the black lines representing the ...
5
votes
2answers
169 views

What's the difference between hypsography and topography?

I've recently come across some data that has been labeled "hypsography". I looked it up and it sounds like topography. But this data source has data labeled "topography" separate from its ...
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1answer
143 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 ...
1
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1answer
271 views

What is the highest obtainable resolution of FREE elevation data in the UK?

I am seeking closure with this question guys. I am aware of various sources of free elevation data ~30+ m, and I have been searching for higher resolution FREE data for a while now. This already ...
3
votes
1answer
62 views

How is elevation and altitude measured?

According to my watch that claims to measure altitude, as far as I can see it says that in Stockholm Sweden the altitude is 170 meters but can that be right? How exactly can we know that 0 altitude in ...
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2answers
58 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
votes
1answer
346 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 ...
0
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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
votes
1answer
288 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
vote
1answer
85 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
votes
2answers
279 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 ...
0
votes
2answers
878 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
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 ...
1
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0answers
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 ...
0
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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.
5
votes
1answer
516 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
votes
1answer
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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0answers
236 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
votes
3answers
227 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
201 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
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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votes
0answers
89 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. ...
0
votes
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- ...
1
vote
2answers
161 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 ...
1
vote
1answer
120 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
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 ...
3
votes
3answers
850 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
361 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 ...