CODEWITHSUNDEEP
c#geolocationcoordinatesbing-maps
Mehdi Bugnard
Mehdi Bugnard

Reputation: 3979

How to calculate the coordinates of the 4 corners (edge) of the map with BingMap?

I work with bing from some days. I can display an image with my bing map coordinates lontitude and latitude.

But I would like to calculate the coordinates of location in the 4 edges of my image. For now the only thing I know is the central point of origin. The problem is that I'm limited to API. I work for a games xna c # and unfortunately can not use the Class Map from microsoft :-(. http://msdn.microsoft.com/en-us/library/hh846504.aspx

I know the following values: (sample value)

LevelZoom: 17

ImageWidth: 800 px

Imageheight: 800 px

Lat: 46.6023

Longitude: 7.0964

Is it possible to calculate the coordinates of the 4 corners of my image with these 5 values ​​known? Here is a drawing explaining what I want. enter image description here Thanks a lot

Upvotes: 2

Views: 2590

Answers (1)

Arno 2501
Arno 2501

Reputation: 9397

Based on the scale 1.19 m/pixel given by the bing maps api for a level 17 zoom this gives us 800 * 1.19 = 95'000 meters edges (http://msdn.microsoft.com/en-us/library/aa940990.aspx)

You should be able to calculate it this way : (alorithm : https://gis.stackexchange.com/questions/2951/algorithm-for-offsetting-a-latitude-longitude-by-some-amount-of-meters)

 //Position, decimal degrees
 lat = 46.6023
 lon = 7.0964

 //Earth’s radius, sphere
 R=6378137

 // DO THE SAME FOR B C D

 //offsets in meters for A
 dn = -47600
 de = -47600

 //Coordinate offsets in radians
 dLat = dn/R                      // -0.0074629942881440144669203562106
 dLon = de/(R*Cos(Pi*lat/180))    // -0.00746374633301685016002447644032

 //OffsetPosition, decimal degrees
 latA = lat + dLat * 180/Pi // 46.174701924759107796879309401922
 lonA = lon + dLon * 180/Pi // 6.6687588357618898589751458712973

This use a simplified flat earth calculation which is not the most accurate method but should meet your need though.

Upvotes: 4

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