21
votes
Accepted
Meaning of "Elevation above surface of ellipsoid"?
The elevation above the ellipsoid (ellipsoidal height) is the elevation above a mathematical model that approximates the shape of the earth. The current most common one is WGS84. These are the ...
- 3,071
11
votes
Accepted
Why is SQL Server 2019's STDistance Very Slightly Different Than The Vincenty Formula? (Same Up To ~0.0001km)
SQL Server's STDistance function does not compute geodesic distances. Its algorithm essentially generates straight lines in 3D, densifies them and maps them on the ellipsoid in a manner described more ...
- 3,746
7
votes
Accepted
Difference in destination location between pyproj and geopy
It looks like you've done everything correctly. You can evaluate the errors from each method by performing the inverse calculations to find the distance given the origin and destination coordinates, ...
- 41.3k
5
votes
Difference between Vincenty and great-circle distance calculations?
My apologies for posting a second answer here, but I taking the opportunity
to respond to the request by @craig-hicks to provide accuracy and timing
comparisons for various algorithms for computing ...
- 3,176
5
votes
Meaning of "Elevation above surface of ellipsoid"?
An ellispoid is a mathematical model of the earth that approximates its three dimensional shape. See this definition. Elevation on top of the ellipsoid is 0, but since it's just an approximation one ...
- 1,571
4
votes
Accepted
How to measure distance between 2 GPS points in Pandas?
You can do it like this:
Cross join the two dataframes using pd.merge. (The key field is just an auxiliary to be able to compute a full cross join.)
df_all = pd.merge(df.assign(key=0), df_loc.assign(...
- 1,304
4
votes
Accepted
Translating X, Y coordinates to lat/long
Based on your comments there are two steps here:
Translating your known coordinates in latitude and longitude to the projected coordinates of EPSG:32723.
Calculating the distance to a given cell.
To ...
- 15.6k
3
votes
Why is SQL Server 2019's STDistance Very Slightly Different Than The Vincenty Formula? (Same Up To ~0.0001km)
Without having access to the source code of SQL Server it may be impossible to say. As a comparison, PostGIS ST_Distance query from the geography example of https://postgis.net/docs/ST_Distance.html ...
- 60.1k
3
votes
Difference in destination location between pyproj and geopy
The geopy pull request fixes your issue with geopy. You will need to
install the python package geographiclib first with
pip install geographiclib
- 3,176
2
votes
Meaning of "Elevation above surface of ellipsoid"?
An "ellipsoid" is a mathematical approximation of the shape of the Earth. Many different ellipsoids exist, but the two most widely used today are the GRS80 and the WGS84, which attempt to provide a ...
- 464
2
votes
Difference between Vincenty and great-circle distance calculations?
Whether using vincenty or haversine or the spherical law of cosines, there is wisdom in becoming aware of any potential issues with the code you are planning to use, things to watch out for and ...
- 121
2
votes
Difference between Vincenty and great-circle distance calculations?
It appears that the geopy.distance package offers a function "distance()" which defaults to vincenty(). I would recommend using distance() on principle, as it is the package recommendation, in case ...
- 133
2
votes
Accepted
Haversine accuracy worse when using geocentric radius vs average Earth radius
Ok I figured it out after some research. Instead of using the Geocentric radius I instead calculate the radius Use the “Radius of Curvature formula at azimuth α” formula from the paper (page 5):
http:/...
- 21
1
vote
Vincenty or (Project + Euclidean) for accurate distances
GeographicLib has the highest accuracy for measuring distances on ellipsoids of revolution, with a published accuracy of less than 15 nm.
For example, using GeodSolve to solve the inverse geodesic ...
- 41.3k
1
vote
Vincenty or (Project + Euclidean) for accurate distances
Per your points, your baseline is about 100m. I've made tests about this before, and on such short distances it barely makes a difference (in fact, sphere-Earth calculations such as haversine give ...
- 3,081
1
vote
Vincenty or (Project + Euclidean) for accurate distances
The scale factor – a measure of linear distortion – of national projected coordinates typically (e.g., for UTM) range between 0.9996 and 1.0010. In places this would amount to more than 1m,...
- 8,798
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