Here’s what worked for me, without so much bs. int x = (int) ((MAP_WIDTH/360.0) * (180 + lon)); int y = (int) ((MAP_HEIGHT/180.0) * (90 – lat)); The lat,lon coordinates were given to me by Android devices. So they should be in the same standard used by all Google Earth/Map products.
I wrote an article about finding the bounding coordinates: http://JanMatuschek.de/LatitudeLongitudeBoundingCoordinates The article explains the formulae and also provides a Java implementation. (It also shows why IronMan’s formula for the min/max longitude is inaccurate.)
The big issue with plotting maps is that the spherical surface of the Earth cannot be conveniently converted into a flat representation. There are a bunch of different projections that attempt to resolve this. Mercator is one of the simplest: it assumes that lines of equal latitude are parallel horizontals, while lines of equal longitude … Read more
Wikipedia gives a pretty thorough discussion of the algebra here: http://en.wikipedia.org/wiki/Trilateration The first step, not really covered in the Wikipedia entry, is to convert your lat/long coordinates to Cartesian coordinates: x0 = cos( lon0 ) * cos( lat0 ) , y0 = sin( lon0 ) * cos( lat0 ) , z0 = sin( lat0 ) … Read more
Here is the query I use on the store locator I work with: SELECT `id`, ( 6371 * acos( cos( radians( :lat ) ) * cos( radians( `lat` ) ) * cos( radians( `long` ) – radians( :long ) ) + sin(radians(:lat)) * sin(radians(`lat`)) ) ) `distance` FROM `location` HAVING `distance` < :distance ORDER BY … Read more
For latitudes use: Decimal(8,6), and longitudes use: Decimal(9,6) If you’re not used to precision and scale parameters, here’s a format string visual: Latitude and Longitude ##.###### and ###.###### To 6 decimal places should get you to around ~10cm of accuracy on a coordinate.
No Library, No Nothing. Copy This! Using These Two Classes , You can Convert Degree(latitude/longitude) to UTM and Vice Versa! private class Deg2UTM { double Easting; double Northing; int Zone; char Letter; private Deg2UTM(double Lat,double Lon) { Zone= (int) Math.floor(Lon/6+31); if (Lat<-72) Letter=”C”; else if (Lat<-64) Letter=”D”; else if (Lat<-56) Letter=”E”; else if (Lat<-48) Letter=”F”; … Read more
The answers to Haversine Formula in Python (Bearing and Distance between two GPS points) provide Python implementations that answer your question. Using the implementation below I performed 100,000 iterations in less than 1 second on an older laptop. I think for your purposes this should be sufficient. However, you should profile anything before you optimize … Read more
This is called Reverse Geocoding Documentation from Google: http://code.google.com/apis/maps/documentation/geocoding/#ReverseGeocoding. Sample Call to Google’s geocode Web Service: http://maps.googleapis.com/maps/api/geocode/json?latlng=40.714224,-73.961452&sensor=true&key=YOUR_KEY
If the latitude coordinate is reported as -6.3572375290155 or -63.572375290155 in decimal degrees then you could round-off and store up to 6 decimal places for 10 cm (or 0.1 meters) precision. If the coordinate reference system (CRS) is not EPSG:4326 (e.g., EPSG:3857) then the x and y values measure a distance in meters from the … Read more