Questions tagged [altitude]

The height of an object or point in relation to sea level or ground level.

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Sudden change in altitude during measurement with GNSS

We work For some time now we have been working with QField and the GNSS receiver from Emlid. We get the accuracy via bluethoot from the receiver to QField. Lately, however, the measurements have been ...
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Including height information when exporting images from SlantView 2

I have a set of images that were collected with a slantrange multispectral sensor (S3P). To include the radiometric calibration information from the sensor, I use SlantView 2 (Ver. 2.17.4). I will ...
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Determing altitude above mean sea level (amsl) or isobaric (hPA) levels for GFS surface coordinates

GFS provides surface coordinates for their data variables, such as for geopotential height, temperature, and u, or v wind vectors, however, it is not clear what the altitude is at the surface. Is ...
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Flight visualization in QGIS

In the CSV file I have accurate data on location, altitude, and time. In Google Earth point by point I manage to create the following visualization, is it possible to create the same visualization in ...
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3 votes
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101 views

Obtaining area modified by altitude using PostGIS

How to change area calculation, making use of altitude? I am supposing that at Z=0 is the default (geoid surface) for PostGIS. So we can expect different area when Z=800 or Z=8000... But, using the ...
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sunAngle() calculation in R giving wrong results

I need to find the hourly sun angle (angle at which the sun strikes the Earth) for a particular position (latitude, longitude) for a given day in Belgium. I used sunAngle() from "oce" ...
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Which height data is correct? [closed]

I own the following device - https://interrex-tracking.com/lego-small/ the device is attached to a bird, and every day I receive information about time and date, X and Y locations, altitudе and geoid ...
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Uncorrected pressure altitude to WGS84 altitude

I'm trying to convert the altitude returned by an ADS-B receiver into its WGS84 altitude. It's been a wild ride trying to determine which type of altitude is returned from ADS-B (I get completely ...
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2 votes
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Trying to delineate areas (riparian zones) from a DEM, with same height difference to a polyline (reach)

I'm trying to delineate riparian zones. The idea is to define a mean depth of the drainage net (constant), and then, draw a buffer around the reaches that will include all the terrain within this ...
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Relation between Solar Radiation and Elevation: Satellite Data

I used DSR (Downward Shortwave Radiation) data from MCD18A1 product and GHI (Global Horizontal Irradiation) data from SOLARGIS to create solar maps: Using this elevation map: I see that the solar ...
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QField: get the altitude into an attribute

I'm trying to collect the altitude from the GPS of my phone in the a field a create. Here's the situation: A have a point geometry file saved in a gpk A field "Altitude", type double And in ...
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Getting altitude with Trimble TDC 100 and QField

In our company we got Trimble TDC 100 and install QFlied for data collection. We collect points and polylines. Our aim is to get vertex and points while saving their altitude (height above the mean ...
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Generating new data in curve (polyline) by interpolation of existing data in this curve

I am trying to add altitude data on the vertex of a polyline in QGIS. I have extracted points from the vector layer of the polyline to update the Z-value. I have altitude for some points, new points ...
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How to properly point the Sun in CesiumJS?

I prepared a Cesium sandcastle example based on this answer from @FSimardGIS, but something is going wrong: only one of many rays correctly points to the Sun, the other appears random. What's wrong ...
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Seeking maps to use on iPhone/Android app

How can I get data of the earth map on the iOS sdk "Swift" containing data altitude too? I would like to use all world map, gps position (but I think that's not a matter) and altitude of all ...
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2 votes
1 answer
134 views

Get altitude value from WMS

If I load a WMS service into QGIS I could query with the selection tool for every pixel the altitude value. Where does QGIS get this altitude value from? A WMS does not normally have any altitude ...
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Altitude information for European highways

I need to calculate the gradient in major European highways. Fot this I need altitude data for each highway, let's say every 100 meters. Are there such kind of data publicly available? If not, I am ...
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Speed of reading a GeoTIFF using geotiff.js

I am have created my own API to return elevations from GeoTIFF files using geotiff.js (https://geotiffjs.github.io/), but it is slow compared to public APIs. For example, table below shows the tests ...
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Why is QGIS not recognising altitude from CSV file?

I used the Google Earth method for creating a KML file of points with latitude, longitude, and altitude as necessary information. After that I converted the KML file to GPX and then to CSV, through ...
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3 votes
1 answer
176 views

GPS: what limits the _rate_ of change in altitude?

I have a GPS tracker/transmitter I use in rockets. I use it to locate and recover a rocket. I realize that Altitude is not the strong suit in GPS, and don't expect it to be really accurate. Neither do ...
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264 views

WSG84, GPS, GEOID and other altitudes

INTRO A bit of tool introduction, but the problem is not related to this directly. I have an app in CesiumJS. I am using Cesium World Terrain, and get altitude using Sample Terrain Most Detailed ...
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Correcting slope of river bed on DEM using QGIS or ArcGIS

I have a DEM that has incorrect value of altitude/slope in the river bed area. This is a result of the interpolation of elevation value that are close to the river and creates lots of errors. In fact ...
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140 views

Android app to get altitude of places to use in field visit?

I want to verify the height of the ground which is provided to me with the help of an app if available. Of course, I am aware an app will not give me exact value but for me, it works if it shows ...
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Extracting data from ASCII file? [closed]

I have ASCII files for a country that map altitude. I'd like to extract information on slopes for specific cities in my country. My goal is to have at least a rough idea of physical constraints in ...
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TIFF to KMZ passing altitude data

I am currently trying to create a KMZ from a GeoTIFF by using gdal_translate. This Works fine and I am accomplishing this by using by using this command gdal_translate.exe -of KMLSUPEROVERLAY c:\in....
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WGS84 to MSL and opposite

I am using CesiumJS to create point in a map using World Terrain to get the elevation of my points. The point in Cesium are using WSG84. When I calculate the altitude using sampleTerrain I retrieve ...
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Altitude differences in different CRS

Currently I am working on a project in Kosovo. After gaining autonomy the country "invented" their own CRS, which is driving me crazy sometimes. It doesn't even have an EPSG-Code, it goes by "Kosova ...
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Adding Altitude to a marker in WebGLEarth

Im trying to add an altitude to a marker in WebGLEarth but i cant figure out how to do it. I cannot find anything in documentation either. The idea is that my markers act as satellites so i need the ...
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Qneat3 / shortest distance calc sensitive to altitude?

I'm trying to calculate shortest distance using Qneat3 (using both the shortest path and OD-matrices for different purposes). And am wondering if there is any possobility to factor in altitide (it is ...
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Convert MSL to WGS height

I need to find the coordinates for a given location in WGS coordinates. This mean geodetic latitude, longitude, and altitude (with respect to the reference ellipsoid). I was informed the coordinates, ...
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Focal length vs Principal point

I have set of areal imagery. One of a parameters I get with images is camera's Principal Distance , what I'm looking for is Focal length, but I don't have Focal length at the moment I tried to ...
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How to plot a point on the highest elevation of a raster on a polygon. QGIS

I have a shp with more than 1700 polygons on a elevation raster. I need to plot a point that represents the highest altitude location within the polygons, and then export those points as a new shp.
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Why is my aspect not displaying the full data?

I am trying to get the slope aspect for the altitude shown above. Can someone please advise me on why this may not be working properly?
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2 votes
1 answer
989 views

Is kml altitude mode "absolute" equivalent to altitude over WGS84 ellipsoid?

I am working with an aviation software which outputs points with altitudes over WGS84 ellipsoid. Now I want to represent those points in Google Earth, writing a kml file. I know I have to convert the ...
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1 answer
368 views

GPS Altitude uncertainty and postional uncertainty in Lat/Long [closed]

I'm working on flight sensors for a project and I'm supposed to model GPS device noise. I looked a lot for it online and could not get a convincing answer. I need the uncertainties of altitude and ...
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6 votes
2 answers
4k views

Choosing datatype for holding Latitude, Longitude and Altitude in PostGIS?

I'm trying to take advantage of the many functions available in Postgis for dealing with latitude and longitude coordinate systems. However, I would like to add some altitude information to my ...
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ISA Model and GFS data

I have a newbie question... I always used the International Standard Atmosphere model whenever I needed to calculate the temperature in a given altitude. It always looked accurate to me... However,...
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1k views

Correcting incorrect altitudes of points recorded by my Android or how to calculate Geoid Height in QGIS

I tried to edit my question with more details and I also think that lot of people can benefit from this question! I was recording a track with my Android and later I found out that I end up having ...
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5 votes
2 answers
8k views

Inaccurate altitude GPS data with my Android?

I've been recording tracks with GeoTracker on my Android. In places I have points that have altitudes higher than the peaks of a mountain. Like one altitude difference is 46 m. How is it possible to ...
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3 votes
2 answers
371 views

Does Magnetic Deviation depend on altitude? [closed]

Magnetic declination, sometimes called magnetic variation, is the angle between magnetic north and true north. Declination is positive east of true north and negative when west. Magnetic ...
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2 votes
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991 views

Height above sea level measurement

I would like to use height above sea level in the gravity equations. What is the source for getting it? Can i use altitude measurements from Altimeter or GPS 'z' measurement? For your kind information,...
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Calculating highest point, lowest point, average altitude in specified area around click position in Cesium? [closed]

I have successfully computed the height of a location where user clicks in cesium but my next step is a bit complex. What I want to do is that when user clicks at some point on globe, at any zoom ...
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3 votes
2 answers
141 views

Exporting grid line nodes with ELEV attributes as data frame? [closed]

I would like to have a data frame of nrow x ncol where nrow = rows of my grid lines and ncol = col of my grid lines. The purpose is to use the ELEV data for 3D topography modeling in R. This is what ...
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1 vote
0 answers
56 views

Use of Airbus WorldDem altimetric values (EGM2008)

In France, the altimetric values are issued from a mesure of heights above the sea level based on the Marseille's tide gauge. If i didn't mess it up, the system is named NGF - IGN69 for mainland (See ...
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QGIS: Show line ELEV on hover or select?

I've installed the value tool plugin, but cannot figure out where it outputs. I tried map tips in qgis. How can I see the elevation of a line or selected point on hover or select?
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2 votes
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283 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 ...
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2 votes
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Three-Dimensional Routing

I have created a route by hand using the Tracing Tool available in QGIS, placing the waypoint on top of an Open Street Map layer. I wanted to export all the coordinates to another program, so I saved ...
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1 vote
1 answer
669 views

Extract height values from vector to CSV

I have generated a CSV file (using the MMQGIS plugin) expecting to obtain all the coordinates of a vector layer that I have created. But the output file only contains the latitude and longitude ...
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2 votes
1 answer
193 views

Get Altitude for Multiple Objects

I use QGIS and I has two layers: one with point objects (more than 1000) and one with surface (it is a version of DCW). I want compute altitude of all points. Basically, I want to get an array where ...
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Faulty altitude point between contours

I have point(picket?) between 2 contour lines with even number altitudes. Now i got these new 5 meters steps contour in between. As you see, this point between red lines was OK, but now that this 175 ...
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