Questions tagged [elevation]

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
2k 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 ...
3
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1answer
2k 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 ...
3
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2answers
279 views

Obtaining nodata information for ASTER datasets?

Is there any way to determine what the nodata value should be, in a set of geotiff images that do not have the 42113 tiff tag ? I am trying to get elevation information, programatically in c++, and ...
3
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1answer
351 views

Change ellipsoid reference for altitude in a DEM

I have DEM data stored as RGF93 (Lambert-93) for lat/lon and NGF-IGN69 for altitude. I'm trying to change the reference ellipsoid for the elevation data (ultimately to NTF, but WGS84 would be fine to ...
3
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0answers
84 views

Effectively applying cpt-city colour ramps to elevation in QGIS3

There are lots of nice topography and bathymetry colour ramps provided by cpt-city in QGIS. However, I cannot find a straightforward way of specifying the transition from blue (below sea level) to ...
3
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0answers
83 views

Converting Surface Model to Elevation Model?

Is there a way to convert a digital surface model (DSM) to a digital elevation model (DEM) in QGIS? Surface models contain lots of noise (e.g. trees, buildings) when I only want to show the ground. ...
3
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0answers
59 views

Checking and enforcing downstream Z constraint for synthetic streams?

Assume I've delineated planar (X, Y) stream breaklines to use them for enforcement of bare ground DEM derivation from high density lidar data. The stream features are in a Z and M enabled polyline ...
3
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0answers
203 views

Which STRM resolution Srtm2Osm.exe uses?

The piece of program Srtm2Osm uses SRTM elevation model from NASA to produce countour lines in OSM format. Does it use the SRTM1 at 30m or SRTM3 at 90m?
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0answers
83 views

How can ASTER elevation data be converted to a CAD model? [duplicate]

I am trying to convert ASTER elevation data to a 3D CAD model using only opensource software. I have tried using different file formats but I have been unsuccessful. I use QGIS for my GIS work and ...
3
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0answers
232 views

Elevation statistics for a given Area

I am attempting to determine the best way to calculate the Minimum and Maximum elevation for a defined area. The area is defined by an IPolygon The elevation is defined as an ISurface Possible ...
3
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1answer
1k views

How can I programmatically project the Z value of a z-aware feature point, using ArcObjects in .NET/C#?

I discovered the following code leaves the Z coordinate of featurePt untouched: // if not WGS84 project it if (!SpatialRefsEqual(featureSpatialRef, srWgs84)) { // featurePt here is a Z-Aware ...
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2answers
662 views

Obtaining elevation data for points using QGIS [closed]

I am new to QGIS. I have points uploaded to QGIS that were collected from a GPS, and I need to get elevations for each point (I don't trust the elevation estimations of my GPS). What is the best ...
2
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2answers
413 views

Calculate pixel value in arcmap

I want to change pixel values of elevation data. I want to change values meter to feet. So i need to multiply pixel values with 3.2808. How can i do that in arcmap?
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5answers
11k views

Creating Slope Map Using Contours in ArcGIS Desktop?

I am trying to create a slope map. I have many contour elevation files. I tried to use the slope tool in ArcToolbox, but it calls for raster files and I'm working with vector data.
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2answers
597 views

Algorithm for smoothing DEM without losing max and min elevations

I am looking for a method/algorithm for smoothing a DEM raster similiar to something like lowpassing, however I want to keep the highest and lowest points, resp. peaks. Latter often are only ...
2
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1answer
639 views

How to calculate mean elevation in a DEM between a specific interval?

I have a DEM with different elevations between 100 m & 3828 m. I just want to calculate mean elevation higher than 1500 m? Can I do that?
2
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1answer
227 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 ...
2
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2answers
1k views

Get values of terrain elevation of roads in QGIS?

I have one DEM raster layer with elevation values and one vector layer of the roads; same size, extension and CRS. I want to do what this guy did here: http://youarealegend.blogspot.de/2012/07/...
2
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1answer
1k views

Displaying DEM with real elevation values in ArcGIS Desktop?

I am trying to create a DEM with hillshading map in ArcGIS Desktop 10, but I'm getting the result with scale values between 0 and 254. How can I display the scale with the real elevation values? ...
2
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1answer
2k views

How to create a buffer considering the true surface area of the landscape?

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 surface area of the landscape (...
2
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2answers
117 views

Why does Blender not accept DT2 file (elevation data from EarthExplorer)?

Trying to do the Creating Shaded Relief in Blender tutorial https://somethingaboutmaps.wordpress.com/2017/11/16/creating-shaded-relief-in-blender/ Got the file from SRTM 1 Arc-Second Global. Got ...
2
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1answer
223 views

How can get correct elevation values from Digital elevation models

I am a bit new to spatial data analysis. I am trying to analyse elevation data for a coastal (almost flat) city with the highest elevation of about 30m. I have DEMs from ASTER, SRTM, and a DSM from ...
2
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1answer
59 views

Handling an irregularly shaped elevation raster file

We are trying to process a set of elevation rasters of increasing resolution. We have a 30m resolution file that covers a large area, and a 5m resolution file that looks something like this image. ...
2
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1answer
126 views

Check if a polygon is at one elevation

I have a polygon (pond) and I need to ensure it is at one elevation. I have converted all vertices of the polygon to points, used summary statistics to determine the range in elevations and if the ...
2
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1answer
925 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 so ...
2
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1answer
1k views

DTED/GeoTiff layer: Get elevation under mouse pointer

I have a simple desktop app with a map control. The map data that will be available to show will be either DTED files (Military Analyst's catalog / MADTEDLayer), or GeoTiffs (created by gdal). I want ...
2
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2answers
8k views

Can WMS be used to get a local copy of raster data?

I have tried reading up on WMS on wiki and other sources but haven't managed to get my head around a couple of points. 1) Using WMS is it possible to get a local copy of the raster data (say a tiff ...
2
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1answer
152 views

Line of Sight between sets of two points each

So I have a list of points with their longitude and latitude (Lon_A, Lat_A and Lon_B, Lat_B). I also have a DEM layer from the SRTM for the relevant location. I need to check if line of sight exists ...
2
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1answer
71 views

Points along lines at set elevation intervals [closed]

I am looking for a way to create points along lines (roads) at set elevation differences (0.5m height differences) using QGIS.
2
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2answers
1k views

Source of Contour Lines for QGIS

I am planning to go on multiple days hike and used Wikiloc to download GPX tracks. We will use a GPS for our navigation but I always want a printed map as a backup. Maps for that area are notoriously ...
2
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2answers
232 views

Increasing Flood Plain

I am doing a project where we are attempting to determine how many more buildings would flood if the FEMA flood plain increased by 1',2' and 5'. I have the elev of the flood plain rasters from lidar ...
2
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1answer
99 views

Contour vs elevation semantics

I accept I am being a pedant here, but feel the semantics are important.. If I were to drawn a path representing a 'route' between 3 random points on the earth's surface, then establish the nearest ...
2
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1answer
374 views

Is there any difference between a stream's Longitudinal Profile and its Elevation Profile?

I have derived elevation profile of a river channel using USGS SRTM 1 ArcSec. I am interested to know whether Elevation Profile and Longitudinal Profile are synonymous?
2
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1answer
195 views

Is elevation (height relative to sea level) constant, despite sea level rising?

Is a 10,000' peak still a 10,000' peak if sea levels have risen a foot? Is it a 9,999' peak now, or is elevation just a constant? Seems odd that a patch of land a few feet above "sea level" could sit ...
2
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1answer
1k views

In R's raster::terrain function, which way is north?

The terrain function in R's raster package calculates slope and aspect from an elevation raster: see http://www.inside-r.org/packages/cran/raster/docs/terrain. With the unit="degrees" option, the ...
2
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2answers
926 views

Finding point with highest elevation in area using ArcObjects?

Is there a way to find a point with highest elevation in specified area by using ArcObjects? Let's say that I have a raster with DEM and I would like to establish some areas of interest in this raster....
2
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1answer
301 views

How do I find out the sea levels?

I have following elevation data of a region (the higher the altitude, the brigher the points): How can I find out, which areas are filled by water, and which not? Can I assume that if the elevation ...
2
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2answers
4k views

Modifying DEM elevation data in QGIS using a polygon

I've tried searching through the existing questions but am struggling to find a succinct answer to what I am trying to achieve. For background, I am running a flood model in TUFLOW to help support a ...
2
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2answers
862 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 ...
2
votes
1answer
77 views

Reading Elevation Data from a DSM file using Python

I am new to GIS processing and I have a DSM file with a .tif extension. I would like to read the elevation data from this file using python or QGIS. I can view this file on the delair web ...
2
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2answers
205 views

Adding elevation to point in PyQGIS?

I am trying to add elevation to a 2D point in a QGIS 3 plugin, preferably in a concise and straightforward way. Not finding this easy. I think part of the problem is that in QGIS 3, fromPoint() has ...
2
votes
1answer
970 views

How can I modify DEM elevation data within QGIS using a polygon?

How can I modify an existing DEM using a polygon? I have a DEM raster with terrain varying between 355 and 365 meters. I have a polygon I've drawn over the area. Ideally, I would like to uniformly ...
2
votes
1answer
470 views

Reprojecting XYZ coordinates in Python whilst keeping Z coordinate constant

When doing a reprojection from a projected coordinate system (e.g. EPSG:28992) to a geographic coordinate system (e.g. EPSG:4326), the Z coordinate gets an offset of 45 meters. The Z coordinates of ...
2
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1answer
284 views

GRASS GIS: Interpolate DEM from irregularly spaced coastal survey data

I am attempting to interpolate the elevations of data sets of cross-shore survey transects. The data set size range from 50k to 300k points with ~100m between the transects and 1-5m between the points ...
2
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1answer
102 views

What is elevation relative to in EPSG:2284?

I have some locations in EPSG:2284: (3669486.63386,11293013.10592,709.08004), (3669559.13811,11292972.72831,711.60055), (3669639.51308,11292851.48264,712.22258), (3669800.62304,11292949.38118,714....
2
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1answer
521 views

Google Maps Elevation license

I would like to use Google Maps Elevation API to query elevation data for my future free and open source script. What I would like to know is what is the exact text which I need to include in my ...
2
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1answer
218 views

GDAL's Gnomonic projection — where do I set the elevation?

I have an existing application that uses a Gnomonic projection where the elevation at the origin is added to the earth radius that is used in the projection calculations (6378137 plus elevation in m). ...
2
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3answers
119 views

Elevation graph shows all the profiles starting at the same point eventhough one of them starts farther inland?

I am trying to compare 3 interpolated lines to analyze sediment movement after beach nourishment. Two of the lines start at the same point, but a the 3rd one starts farther inland. However, when I put ...
2
votes
1answer
213 views

Are there any tools that can identify ravines/steep elevation drops from contour line data?

I am trying to create polygons around rivers that extend all the way up to the top of the surrounding slopes. I am currently able to do this using stream data and contour data, but I would have to ...
2
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1answer
195 views

Calculating median elevation for local authority areas using OS Terrain 50

I haven't been able to find anything that could comprehensively help me with my problem. I want to calculate median elevation for UK local authority areas. So far I've taken the OS Terrain 50 data ...

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