Questions tagged [ellipsoid]
An ellipsoid is a closed quadric surface that is a three-dimensional analogue of an ellipse. In geodesy, a reference ellipsoid is a mathematically-defined surface that approximates the geoid, the truer figure of the Earth, or other planetary body.
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Finding the right Projection/CRS for a 2000's era shapefile of Bosnia Herzegovina
I have been looking for a historic soil map shapefile of Bosnia & Herzegovina for a while and finally found one - a UN FAO project archive had the files available, albeit designed for ArcView. The ...
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Intersect a 'circular' sector with a 'square' on WGS84
I wold like to get the intersection(if empty or not) and area of a circular sector defined by the origin(lat, lon), bearing and angle width with a 'square' defined by lines of constant lat and lon on ...
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Making transformations between ellipsoids using PyPROJ
I am transforming coordinates between the Ellipsoids WGS84 and Hayford International using the code
from pyproj import CRS, Transformer
Define CRS objects for WGS84 and Hayford International
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Reprojecting image with ground control points in geodetic CRS to equidistant cylindrical CRS on sphere
I'm working with some satellite data from the Mars Reconnaissance Orbiter context camera (CTX). As a sanity check for some later processing that I would like to do, I'm trying to take the raster data ...
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QGIS ellipsoidal area values changing very slightly between calculations while planimetric values stay the same
I have a number of vector shapefiles that I need to calculate the geodesic/ellipsoidal area for. These shapefiles are accessed and updated regularly, with the area recalculated each time they are ...
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How can Cartesian and ellipsoidal perimeters and areas be so different in an EPSG:3857 layer?
For a particular polygon of mine in a "EPSG:3857 - WGS 84 / Pseudo-Mercator" layer, the derived measurements QGIS reports are:
Ellipsoidal perimeter: 1015 m
Cartesian perimeter: 1218 m
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Projection alignment
I am trying to align my coordinates with known geodesic markers in QGIS 3.34.1 but all my measured points are out with a bearing of about 35 degrees and 2.6m away. My distances are correct when ...
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QGIS measurement tool seems unrealistic
I have created a buffer of 150m around a point. This should give (a polygonal approximation of) a circle with radius 150m.
I tried to verify this with the measurement tool, and I am baffled to see a ...
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Create one-sided-ellipsoid from 'geometry by expression'
I am looking for a way in which, I can create a buffer around a point.
The buffer is meant to be a semi-ellipsoid.
In theory it should be a mixture of 'single_sided_buffer' and 'make_ellipse' ...
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Coordinate reference system for wide areas in Canada
I am using imagery from different sensors (Sentinel 2 and high resolution satellite) in several areas in Canada. I am trying to accurately represent areas (polygons), however when merging information ...
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Convert XYZ file with WGS84 Ellipsoid elevations to EGM96 Geoid elevations
I have multiple files in XYZ format in UTM horizontal + WGS84 ellipsoid vertical that I need to convert to UTM horizontal EGM96 geoid elevations. There are about 250'000 points in a an area that is ...
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How to calculate the curvature of a segment of an ellipsoid
I'm an artist trying to sculpt shapes that I would describe as ellipsoids. I am wanting to sew together fabric to form these shapes, and although I know the dimensions of the ellipsoid I want to form, ...
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How to convert wgs84 from ellipsoidal height to mean sea level i.e. height above goid, with pyproj?
I want to convert wgs84 coordinates with ellipsoidal height to wgs84 coordinates with height above goid. Therefore I have set up a new conda environment and installed pyproj, proj_data, see conda list ...
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Measuring distance using QGIS
Normally if you measure the distance of line and polygon in Cartesian is smaller compare to Ellipsoidal in QGIS.
However, when I am measuring the distance Cartesian system gives greater value compare ...
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Error in WGS84 to Mercator coordinate transformation
I'm trying to convert the (lat,lon) of WGS84 into Mercator (x,y). Below I've listed all the relevant information given in the file.
Datum="WGS84"
Ellipsoid="WGS84"
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