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Jul
11
awarded  Yearling
Jul
11
awarded  Supporter
Jul
11
answered Projection for polygon intersection confined into one hemisphere?
Jun
25
comment Calculated distance doesn't match Google Earth
And I answered the new question, providing a pointer to pypi.python.org/pypi/geographiclib as a possible way to address your needs.
Jun
24
answered Finding coordinate pair at any given distance along calibrated route?
Jun
24
revised Calculated distance doesn't match Google Earth
Add results of asking GE for distances.
Jun
24
comment Calculated distance doesn't match Google Earth
I checked some old correspondence about Google Earth from 2012. I see that GE back then didn't use spherical formulas for distance. However the results weren't consistent with ellipsoidal formulas either unless the flattening was allowed to depend on the position of the points. I will investigate tomorrow.
Jun
24
answered Calculated distance doesn't match Google Earth
Apr
2
comment What is the approximate error of the Pythagorean Theorem vs. Haversine Formula in measuring distances on a sphere at various scales?
Expand sin(A/2) for A small, using sin(x) = x - x^3/6, and you get this result.
Mar
7
comment Does it make sense to create graticules using UTM meters?
An enthusiastic contributor to Wikipedia started using the term "conjugate graticule" several years ago. But the use of "conjugate" is this context is a real stretch (it's borrowed from the terminology for ellipses). I recommend not using the "conjugate" modifier. (The term "conjugate graticule" no longer appears in Wikipedia.)
Mar
3
comment How do I figure out the grid references (Eastings and Northings) necessary to create a circular 1 mile radius around one location?
I'm not sure what I can add...? Did you try working out the results for X' and Y'? Perhaps you need to know that theta could be given in degrees, and then, of course, theta is in [-180d, 180d] (but you need to make sure that this is compatible with the way you're computing sine and cosine).
Mar
3
answered How do I figure out the grid references (Eastings and Northings) necessary to create a circular 1 mile radius around one location?
Mar
2
revised Given a flight path given in latitudes and longitudes, how do I find another flight path that is parallel to the path given?
Figure offset in second case to do a miter join
Mar
2
answered Given a flight path given in latitudes and longitudes, how do I find another flight path that is parallel to the path given?
Feb
24
awarded  Revival
Feb
23
awarded  Enthusiast
Feb
20
revised Relative areas projection independent?
Fix grammar
Feb
20
answered Relative areas projection independent?
Feb
17
comment Defining a line from geographic coordinate points.
The Wikipedia article Geodesics on an ellipsoid is a good resource. It describes the problem and outlines the solution.
Feb
15
comment Meridian convergence. True north, magnetic north and grid north
And in the southern hemisphere, the situation is reversed.