Geo-location on a diagrammatic map

1. A computer-implemented method of locating a point on a diagrammatic map comprising:

storing in a map database a plurality of map features that appear on a diagrammatic map that does not have a uniform scale, each map feature having a geographical location describing a location of the map feature on a standard map having a uniform scale, and a position on the diagrammatic map expressed in terms of an internal coordinate system of the diagrammatic map;

receiving from a client device a geographical point having a corresponding geographical location on the standard map;

selecting a set of map features from among the plurality of map features that appear on the diagrammatic map based on the geographical locations of the map features, the selected map features in the set having geographical locations on the standard map forming a triangle around the geographical location of the geographical point on the standard map; and

determining a position on the diagrammatic map for the geographical point based on a weighted combination of the geographical locations of the map features in the set on the standard map and the positions of the map features in the set on the diagrammatic map.

2. The method of claim 1 wherein the geographical point and the geographical locations for each map feature comprise latitude and longitude coordinates on the standard map.

3. The method of claim 1 wherein selecting a set of map features comprises:

determining a first map feature that is closest to the geographical point on the standard map; and

determining two additional map features wherein the two additional map features and the first map feature are vertices forming a triangle that encompasses the geographical point on the standard map.

4. The method of claim 3 wherein determining two additional map features further comprises:

determining distances from the first map feature to a plurality of map features on the standard map; and

selecting the two additional map features whose distance to the first map feature is the shortest.

5. The method of claim 1 wherein determining a position on the diagrammatic map for the geographical point based on a weighted average of the geographical locations of the map features in the set comprises:

determining a first line between a first and a second of the map features in the set;

determining a second line between a third of the map features in the set and the geographical point;

determining an intersection between the first and second lines; and

determining a contribution of each of the map features in the set to the weighted average based on the first and second lines and the intersection.

6. The method of claim 1 wherein the diagrammatic map comprises a map for a public transit system.

7. The method of claim 1 wherein the diagrammatic map comprises a map of a ski park.

8. A computer-implemented system comprising:

a processor for executing program code; and

a non-transitory computer-readable storage medium storing program code executable to:

store a plurality of map features that appear on a diagrammatic map that does not have a uniform scale, each map feature having a geographical location describing a location of the map feature on a standard map having a uniform scale, and a position on the diagrammatic map expressed in terms of an internal coordinate system of the diagrammatic map;

receive a geographical point having a corresponding geographical location on the standard map;

select a set of map features from among the plurality of map features that appear on the diagrammatic map based on the geographical locations of the map features, the selected map features in the set having geographical locations on the standard map forming a triangle around the geographical location of the geographical point on the standard map; and

determine a position on the diagrammatic map for the geographical point based on a weighted average of the geographical locations of the map features in the set on the standard map and the positions of the map features in the set on the diagrammatic map.

9. The system of claim 8 wherein the geographical point and the geographical locations for each map feature comprise latitude and longitude coordinates on the standard map.

10. The system of claim 8 wherein selecting a set of map features comprises:

determining a first map feature that is closest to the geographical point on the standard map; and

determining two additional map features wherein the two additional map features and the first map feature are vertices forming a triangle that encompasses the geographical point on the standard map.

11. The system of claim 10 wherein determining two additional map features comprises:

determining distances from the first map feature to a plurality of map features on the standard map; and

selecting the two additional map features whose distance to the first map feature is the shortest.

12. The system of claim 8 wherein determining a position on the diagrammatic map for the geographical point based on a weighted average of the geographical locations of the map features in the set comprises:

determining a first line between a first and a second of the map features in the set;

determining a second line between a third of the map features in the set and the geographical point;

determining an intersection between the first and second lines; and

determining a contribution of each of the map features in the set to the weighted average based on the first and second lines and the intersection.

13. The system of claim 8 wherein the diagrammatic map comprises a map for a public transit system.

14. The system of claim 8 wherein the diagrammatic map comprises a map of a ski park.

15. A computer program product, comprising:

a non-transitory machine-readable storage medium having executable computer readable program code embodied therein for locating a point on a diagrammatic map, the code comprising computer readable program code executable to:

store a plurality of map features that appear on a diagrammatic map that does not have a uniform scale, each map feature having a geographical location describing a location of the map feature on a standard map having a uniform scale, and a position on the diagrammatic map expressed in terms of an internal coordinate system of the diagrammatic map;

receive a geographical point having a corresponding geographical location on the standard map;

select a set of map features from among the plurality of map features that appear on the diagrammatic map based on the geographical locations of the map features, the selected map features in the set having geographical locations on the standard map forming a triangle around the geographical location of the geographical point on the standard map; and

determine a position on the diagrammatic map for the geographical point based on a weighted average of the geographical locations of the map features in the set on the standard map and the positions of the map features in the set on the diagrammatic map.

16. The computer program product of claim 15 wherein the geographical point and the geographical locations for each map feature comprise latitude and longitude coordinates on the standard map.

17. The computer program product of claim 15 wherein program code to select a set of map features comprises program code to:

determine a first map feature that is closest to the geographical point on the standard map; and

determine two additional map features wherein the two additional map features and the first map feature are vertices forming a triangle that encompasses the geographical point on the standard map.

18. The computer program product of claim 17 wherein the program code to determine two additional map features further comprises program code to:

determine distances from the first map feature to a plurality of map features on the standard map; and

select the two additional map features whose distance to the first map feature is the shortest.

19. The computer program product of claim 15 wherein determining a position on the diagrammatic map for the geographical point based on a weighted average of the geographical locations of the map features in the set comprises:

determining a first line between a first and a second of the map features in the set;

determining a second line between a third of the map features in the set and the geographical point;

determining an intersection between the first and second lines; and

determining a contribution of each of the map features in the set to the weighted average based on the first and second lines and the intersection.

20. The computer program product of claim 15 wherein the diagrammatic map comprises a map for a public transit system.

21. The computer program product of claim 15 wherein the diagrammatic map comprises a map of a ski park.