The measure of separation between two entities or locations that may or may not be connected, such as two points.

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8
votes
4answers
3k views

How to find the minimum edge to edge distance of polygons?

I have a a map of about 3000 polygons in ArcGIS 10. I'm looking to find the distance between each one of them. I know how to do it using the lat and long coordinates of the centroid, but I'm looking ...
5
votes
5answers
13k views

For every point, distance to nearest polygon of type X?

In ArcGIS how might one calculate as an attribute value the distance to the nearest polygon of type X? Say we have a point layer of wildlife observations and we want to know how far each of them is ...
11
votes
6answers
5k views

Which tools and methods can be used to create isochrones?

I'd like to get an idea for what's involved in creating isochrones for a series of sites, with a reasonable degree of accuracy to the estimates. A general outline would be great, though my scenario ...
8
votes
4answers
1k views

Looking for a fast, open-source raster cost-distance function to use in code

I've been scouring the internet for a fast, open-source cost-distance function that I can embed inside my code. The functionality should basically work like the ArcGIS implementation where I can ...
2
votes
1answer
2k views

How to calculate distance between two locations using stored procedure in MySQL?

I have a database with locations with its lat and long coordinates. The area of locations is quite small with lots of them quite near each other. Im using this stored procedure in my project. ...
2
votes
1answer
636 views

How is distance between zip codes calculated?

Specifically, where can I find a database of zip codes, their lat/lon centers, and intervening "obstacles" (for example, zip codes that are geographically close but separated by the Chesapeake Bay).
5
votes
5answers
758 views

Getting a square mile bounding box anchored by coordinates?

Let's say I have a lat/lng coordinate pair. I want to determine the coordinates that would create a square mile box. The existing coordintae pair would be the top left of the box, and the coordinate ...
21
votes
6answers
14k views

Trilateration using 3 latitude and longitude points, and 3 distances

I want to find out an unknown target location (latitude and longitude co-ordinates). There are 3 known points (latitude and longitude co-ordinate pairs) and for each point a distance in kilometers to ...
15
votes
6answers
4k 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 -- ...
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)?