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

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15
votes
3answers
2k views

How do I find the distance between two coordinates in an ellipsoid?

Lets say I have two sets of latitude and longitude. How do I find the distance between the two locations if I assume the earth is a perfect ellipsoid (with an eccentricity of 0.0167)?
12
votes
6answers
3k views

What tools in Python are available for doing great circle distance + line creation?

I need to use Python to create a great circle distance -- both a number, and preferably some kind of 'curve' that I can use to draw in a client-side map. I don't care about the format of the curve -- ...
7
votes
2answers
2k views

Distance between lat/long points

I am attempting to calculate the distance between two latitude/longitude points. I have a piece of code that mostly works that I yanked from this post but I do not really understand how it works. ...
10
votes
1answer
549 views

Great-circle lines in Equirectangular projection

Just to check that I'm on the right track: Are all great-circles on the sphere and in equirectangular projection (i.e. latitude, longitude pairs) either: meridians (i.e. going pole to pole) of the ...
3
votes
2answers
448 views

What's the difference between vincenty and great circle distance calculations?

Python's geopy package features two distance measurements techniques: Great Circle and Vincenty's formulae. >>> from geopy.distance import great_circle >>> from geopy.distance ...
13
votes
4answers
284 views

Are long lines in shapefiles to be considered geodesics or straight lines in the 2D latlong space?

Is there a definition on how lines connect vertices in the shapefile format? In the simplest case, imagine a line with only 2 points, from 40,-118 to 40,-112 - that's somewhere random in the US - ...
3
votes
2answers
619 views

How do I find the points of intersection between a small circle and a great circle?

I only actually need to intersect a great circle arc i.e. the shortest path between two points, with a given small circle. I found this tutorial for intersecting two great circle arcs, but ...
1
vote
2answers
150 views

Draw great circle rays from a single point along specific directions

How can I draw great circle rays starting from a single given point P (for example, from coordinate [34 N, 116 W] in this map) and along directions D1, D2, ... (for example, 30, 45 and 135 degrees) in ...
2
votes
1answer
118 views

Can I cross the dateline in CartoDB?

I've created a lovely route map in CartoDB, but one of the lines crosses the dateline (from Colorado to Guam, FWIW) and finds its way there by hitting the dateline north of Alaska, bouncing back ...
1
vote
1answer
137 views

Where to start with great circle maps in CartoDB?

I've pulled together a series of maps in R based on Nathan Yau's excellent Great Circles tutorial and a nice zipcode package The maps show how many people from many zip codes descended on a single zip ...