Questions tagged [elevation]
The vertical distance of a point or object above or below a reference surface or datum (generally mean sea level).
92
questions
24
votes
4
answers
54k
views
Extracting elevation from .HGT file?
I want to assign a specific long/lat position on a map to 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 ...
- 369
15
votes
4
answers
6k
views
Elevation profile 10 km each side of 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.
- 161
10
votes
3
answers
34k
views
How to create contour lines from point data using QGIS?
I'm using QGIS 2.4.0 and I have a shapefile of points with elevation data and X and Y coordinates. I'm using windows 7 OS.
The idea is to create a contour line SHP using my point data.
My question ...
- 435
9
votes
2
answers
12k
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. ...
- 273
3
votes
1
answer
8k
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 (...
- 2,653
16
votes
4
answers
11k
views
Calculating elevation profile along line from a DEM?
Given a DEM (Digital Elevation Model) and a line (x1,y1) --> (x2,y2) (paired coordinates (x,y)), how can one calculate the elevation profile or cross-section projected on that line?
I am looking for ...
- 163
15
votes
5
answers
34k
views
Seeking free elevation data for Europe?
Where can I find free elevation data for Europe?
The available resolutions and terms of use are important details that I also seek.
12
votes
2
answers
48k
views
Calculating elevation profile for a polyline in ArcGIS 10?
My elevation data is a floating point tif. I have a road for which I need to calculate the elevation profile, but I can't see the tools to do this.
Can I do this with ArcGIS, with spatial analyst/3D ...
- 10.2k
10
votes
1
answer
9k
views
Python Script for getting elevation difference between two points [closed]
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 ...
- 399
7
votes
2
answers
2k
views
Elevation Profile with labels on waypoints using PyQGIS [closed]
I would like to plot many elevation profiles with labels on specific waypoints (Points of Interest).
In the end it should look like this:
Or like here:
https://www.birdandhike.com/Hike/Mt_Char/...
- 294
59
votes
9
answers
86k
views
Choosing colour-ramp to use for elevation? [closed]
This is maybe rather subjective as it concerns style, but I would like to have a few decent colour ramps for my DEM when it is layed over my hill-shading.
I have created the Swiss hillshade model as ...
- 10.2k
24
votes
7
answers
14k
views
How to download the entire ASTER GDEMv2 dataset?
In October 2011, NASA released the new ASTER GDEM global dataset (30m) and I have been wanting to get my hands on it. The only problem is that it takes forever to download and I do not feel like ...
- 15.3k
12
votes
1
answer
5k
views
What resampling technique should be used to reproject an altitude raster?
Does anyone know whether I should choose: nearest, bilinear, cubic or majority when projecting the WorldClim altitude raster layer?
- 121
7
votes
1
answer
7k
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 ...
- 837
7
votes
1
answer
3k
views
Programmatically download (seamless) NED tiles?
I used to download 1/3 arcsecond elevation geotiffs from extract.cr.usgs.gov using web services. But a few days ago, that stopped working, probably because USGS reorganized their site. I tried ...
- 173
18
votes
5
answers
26k
views
Calculating Topographic Ruggedness Index in ArcGIS Desktop?
Does anyone know how to calculate Topographic Ruggedness Index (a.k.a Terrain R.I.) in ArcGIS Desktop without access to command line ArcInfo Workstation?
"The topographic ruggedness index (TRI) ...
- 28.2k
3
votes
2
answers
400
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 ...
- 31
2
votes
1
answer
4k
views
QGIS elevation and relief shade
I am trying to generate a map with terrain and elevation in QGIS and as a beginner I have followed tutorials
on how to generate contours and hill shades succesfully. However, I don't know what are the ...
- 217
1
vote
2
answers
12k
views
Getting elevation at particular coordinate (lat/lon) programmatically (but offline)?
I would prefer something in python (but I would settle for any programming language) and something that I could install on my own server so the only limitations would be hardware (no throttling, no ...
- 129
42
votes
8
answers
8k
views
Interrupting contour lines beneath elevation labels (instead of using label buffers) using QGIS?
Is there a way to interrupt a contour line beneath an elevation label using QGIS?
- 8,262
16
votes
4
answers
20k
views
Meaning of "Elevation above surface of ellipsoid"?
I'm using implementation of Vincenty's algorithms, and I have their class called "position" that requires lat, lon, and elevation defined by: "Elevation above the surface of the ellipsoid".
What is ...
- 1,809
15
votes
5
answers
17k
views
How to get an elevation profile for a gps track?
I'd like to get a reasonably accurate elevation profile for a track recorded with a GPS (which often has very unreliable altitude data and occasionally none at all, depending on the model.)
Does ...
- 283
14
votes
3
answers
3k
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 ...
- 243
10
votes
4
answers
16k
views
Getting elevation at lat/long from raster using python?
I was wondering if anyone has some experience in getting elevation data from a raster without using ArcGIS, but rather get the information as a python list or dict?
I get my XY data as a list of ...
- 2,536
10
votes
6
answers
2k
views
seeking "Available Sky" implementations
I'm looking for implementations of an algorithm called "Available Sky". ArcGIS (Spatial Analyst or GRID) is preferred, but solutions in GDAL, SAGA GIS or others are perfectly acceptable.
The ...
- 28.2k
7
votes
1
answer
6k
views
Querying Elevation Data in Postgis
Problem: I have a bunch of raster data (DTED) and I want to use this to make elevation queries using PostGIS (if it makes sense). E.g. I want to ask the question "what is the elevation at (lat1,lon1), ...
- 237
5
votes
1
answer
2k
views
Converting elevations into correct units with pyproj?
I am converting a point from wgs84 into a state plane coord system (epsg: 32051, which is defined in US survey feet) using pyproj, but the transform isn't changing the z values into feet:
point_4326 =...
- 614
5
votes
4
answers
4k
views
Google Earth Polygon surface area to follow the curvature of the earth model
Question:
When drawing a polygon in Google Earth with latitude, longitude and elevation values at each node, how do you ensure that the surface area of the polygon also represents the desired ...
- 509
4
votes
2
answers
2k
views
Kriging values greater than the most extreme value of the input layer?
I'll admit I don't understand kriging to the fullest. Yet, I've read that the weights should add up to 1 as in IDW and Natural Neighbors.
However, surrounding the biggest elevation points of my ...
- 646
4
votes
1
answer
1k
views
Performing viewshed analysis with Dutch AHN files in QGIS?
i downloaded the new (dutch hight data) AHN files, and was trying to perform a viewshed analysis at some point near UTRECHT.
The plugin (grass plugin) works ok, i tried it before with a dem map.
...
- 459
4
votes
2
answers
1k
views
Extracting peaks from DEM and creating 5 m elevation buffer around each peak in ArcGIS Desktop?
I have a DEM available and would like to identify all the peaks that are likely to be bare rock. I want to be able to isolate these areas and create a 5m elevation buffer around them to represent the ...
user107580
4
votes
1
answer
389
views
Creating color physical map using SRTM V2 GeoTIFF tiles in QGIS
Trying to make a physical map (don't pay attention to the colors, I'm experimenting). The map is based on DEM SRTM V2.
But I have experienced some trouble with making a smooth transition between ...
- 347
3
votes
3
answers
9k
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 ...
- 89
3
votes
3
answers
5k
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, ...
- 5,797
3
votes
2
answers
3k
views
Plotting and analyzing extracted elevation data in R?
I have a shapefile of county boundaries for New York state and elevation data downloaded through the elevatr package.
library(elevatr)
library(raster)
library(sf)
library(USAboundaries)
counties <...
- 434
1
vote
1
answer
992
views
Replicate elevation profile extraction (3D Analyst toolbar) in ArcPy
How can I replicate in ArcPy the 3D Analyst Toolbar operations which extract an elevation profile from a transect line drawn atop an elevation layer? This will be incorporated into an automated ...
- 443
14
votes
2
answers
3k
views
What is smallest contour interval possible when derived from DTM?
I am converting a 2m DTM to contours, and would like to have the smallest interval possible.
Is there a theoretical limit, or even a rule of thumb for defining contour intervals based on the ...
- 6,127
14
votes
1
answer
1k
views
Creating Buffer Polygon following Elevations using ArcGIS Desktop?
What I'm looking to do is put a 100 m buffer on a polygon, but rather than the buffer being at a fixed width "as the crow flies" I want it to follow the slopes of my Lidar DEM.
I have ArcMap (with 3D ...
- 141
11
votes
2
answers
1k
views
Elevation profile sample point algorithm
In generating an elevation profile, samples from the underlying raster must be taken. If the objective is to create a profile of maximum quality, how should the locations of sample points be ...
- 6,127
11
votes
2
answers
1k
views
Generating DEM from isolines and spot heights using GRASS?
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 ...
- 660
11
votes
3
answers
24k
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
{
"...
- 537
10
votes
3
answers
20k
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 ...
- 203
9
votes
4
answers
6k
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 "hypsography"...
- 1,824
8
votes
7
answers
6k
views
Is there an online tile-based elevation service?
I am working on an application that requires the elevation at a given lat/long coordinate for lots of closely spaced coordinates along any given irregular path. (The path is a trace of a glider/hang-...
- 181
8
votes
2
answers
9k
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?
- 81
7
votes
1
answer
1k
views
Which is better for measuring actual ground elevation, NED or SRTM?
I know that NED DEM layers are created using mainly Lidar point clouds and that the SRTM derives its data from shuttle-based radar. I have both of these loaded into QGIS and can see that over my study ...
- 2,314
6
votes
2
answers
6k
views
How to read GeoTIFF using PHP?
My current pet project involves creating a web service that uses the CGIAR SRTM worldwide elevation data set. Each request to the service will query for elevation data from a small geographic area.
...
- 163
6
votes
1
answer
8k
views
Displaying elevation profile and storing DEM elevation back to KML line using 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 ...
- 1,237
5
votes
1
answer
4k
views
How to obtain a DTM/DEM from DSM
I need to obtain a grid of bare ground elevation (removing all edifices, trees, roads and man-made elements) for quantitative geomorphological analysis from a high resolution (1 m) DSM obtained by ...
- 53
5
votes
1
answer
1k
views
QGIS: Edit elevation in DTM to get correct slope of a river
I am new to QGIS and just need it to do a hydrolocic analysis of an area of which
I later make a flow model with HEC-RAS 2D.
I made it according to this tutorial: https://www.youtube.com/watch?v=Ro-...
- 51