Any line bisecting the surface of a sphere into two equal halves.

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1answer
50 views

How a draw a circle (on the surface of earth) on a mercator projection?

I would like to use R and leaflet to draw a circle (a real circle on the surface of the earth) on a mercator projection. In the following code, I have the center of the circle (with lng=0 and lat=60),...
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votes
1answer
17 views

How to find midpoint of 2 geographics locations?

I am trying to write a C++ program which finds the geographic center of two locations (defined by latitude and longitude, I can ignore the altitude). This center point shall be on the halfway of the ...
3
votes
0answers
105 views

Which projection can I use to see alignments on great circles?

I want to put on a QGIS map some historical sites to check if they are aligned. If an alignement exists, the points should stay on a great circle (is this correct?). I want to visually verify this ...
2
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0answers
381 views

How to prevent cross-world lines in ggplot world map?

I'm having issues displaying 'great circles' paths and polygons in ggmap, an extension of ggplot2. Please enter the following code to replicate my issues: https://gist.github.com/Robinlovelace/...
2
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0answers
173 views

Air corridor in spherical surface: calculating great circle tangent points with small circles

I have the necessity to draw on a sphere (earth) an air corridor. In the cartesian plane, this corridor is made by some circles and from outer tangents that connect these circles as you can see in ...
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0answers
781 views

Lines as Great circles on a map

How can I get line features to appear as great circles on a map, instead of straight lines? Thanks,
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19 views

What shows the Tissot's indicatrix on a mercator projection?

While reading this post on Quora: https://www.quora.com/Why-does-Google-use-the-Mercator-projection-on-their-maps-as-opposed-to-an-equal-area-proportion-map, I understand that with a mercator ...