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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220 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 ...
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3answers
3k views

Seeking alternative to Google Maps Elevation API?

The Google Maps Elevation API lets me pass a URL like https://maps.googleapis.com/maps/api/elevation/json?locations=39.7391536,-104.984703 along with a developer key, and get a result like { "...
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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? ...
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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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1answer
145 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 ...
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1answer
54 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. ...
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3answers
3k views

How to update the Z value using an UpdateCursor?

I have created the following script to mimic the ArcGIS 3D Analyst tool, FeatureTo3DByAttribute, which creates a 3D copy of a 2D feature class and sets the Z to a specified attribute. import arcpy, ...
2
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1answer
125 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
914 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 ...
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2answers
7k 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 ...
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2answers
334 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 ...
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2answers
190 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 ...
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2answers
535 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/...
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1answer
248 views

ArcGIS: how to obtain an average elevation for grid squares superimposed on a DEM? [duplicate]

Given the DEM of a certain Country, and a fishnet that is superimposed on it, I need to compute the average elevation and slope corresponding to each square in the fishnet. [I am using ArcGIS 10.3.1, ...
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1answer
239 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
168 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
948 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 ...
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2answers
804 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
279 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 ...
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2answers
3k 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
845 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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2answers
77 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
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1answer
253 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
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1answer
238 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 ...
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1answer
222 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 ...
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1answer
88 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....
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1answer
2k views

Terrain() function for computing slope and aspect from elevation data always returns NA

I'm facing a problem with the terrain() function in the raster package (in R) since yesterday. I'm working with elevation data and coordinates in Lambert 72 (espg registry : "+init=epsg:31300"). Here ...
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1answer
439 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
167 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). ...
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3answers
87 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
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1answer
92 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 ...
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2answers
544 views

ASCII Raster format cellsize

I have a particular .asc file, with elevation data in it. I am wondering if somebody knows, what is the unit for the "cellsize" variable in the header of the .asc file? Here is how the header looks ...
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2answers
1k views

Computing the elevation angle of a GPS satellite with respect to the given receiver location

can anyone source an explicit formula for calculating the elevation angle for a GPS satellite as seen from a receiver. I can't seem to find one. Even a text reference would be great. I couldn't quite ...
2
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1answer
3k views

Using GDAL in python to read elevation at a point from 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 ...
2
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1answer
735 views

Obtaining average value around polygon in raster for different cross sections?

I have elevation data in a raster, river (blue line) and the flooded area (black polygon) as shown in the image below: I want to find the water depth in the flooded area (inside the black polygon). ...
2
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1answer
146 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 ...
2
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1answer
187 views

Make a ground mask raster with the Greater Than tool

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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2answers
704 views

How to determine elevation of points in shapefile from second shapefile 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 ...
2
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1answer
722 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 ...
2
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1answer
448 views

How can I calculate elevation from relief?

I have an SDE Raster that displays relief, but I want to display elevation. How would I go about doing this?
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3answers
3k views

Downloading 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 ...
2
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1answer
99 views

How do I use a Simple Feature Collection (sfc) from the sf package with the elevatr package to load elevation data?

I'm trying to load elevation data from AWS using the elevatr package, with a region defined as a Simple Features Collection from the sf package. Here's a simple example: library(elevatr) library(sf) ...
2
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1answer
200 views

Calculating floodplain for river section using DEM only in ArcGIS Desktop?

I'm looking to create areas where water might go when a river floods its banks. I have a pretty good resolution DEM (5ft^2 for each "square"). I'm not looking for anything super accurate or precise ...
2
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1answer
158 views

GDALDEM hillshading running slow?

I have, for a while, been trying to make a terrain map using NASA's SRTM 3 dataset. I have a large (13 GB), geotiff projected to web mercator of all the elevation files provided. I have been able to ...
2
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1answer
439 views

Locating flooded area by creating buffer with elevation around points using ArcGIS Desktop?

I have a shapefile with points, that each have an elevation in their attribute tabel, based on how high the water level is, at a given return period. I need to create a buffer around these points at ...
2
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1answer
933 views

OpenLayers: line elevation profile with slider

I have an OpenLayers client displaying tracks from a vector source. I would like to display an elevation profile of the track. When hovering mouse on a point on the elevation profile, a marker should ...
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1answer
57 views

Contour lines/ basement contour extraction

My purpose: getting out area between elevation contours (like b/w 600m and 700m). The contours could either be elevation ones or the basement contours. I got elevation contours using spatial analyst ...
2
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1answer
43 views

How do I know topo layer contains DEM-altitude? ArcMap 10.3

How do I know if a topographic layer contains DEM-altitude? ArcMap 10.3
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1answer
1k views

Download of very detailed DEM files for Portugal?

Operating system: Windows 10, 64 bit. QGIS Version: 2.13.3 which I installed via the QGIS.org website. I need contour lines for a small area in Portugal. I saw a guide posted here: http://planet....