Convert long and lat to Coordinates on country only

Question

enter image description here the map of japan with pointer on it...

The problem is what will be the formula to to convert the lat ang long to get the right coordinates with the map of japan only..

i use php gd with both image the map and the pointer..

i already manage to plot the right coordinate in whole world using with this code --->

function getlocationcoords($lat, $lon, $width, $height)
{
   $x = (($lon + 180) * ($width / 360));
   $y = ((($lat * -1) + 90) * ($height / 180));
   return array("x"=>round($x),"y"=>round($y));
}

Any Help is appreciated..

thanks...

I don't understand what the problem is. Please describe it more clearly. — deceze, Jan 06 '14 at 08:18
You'd start by getting the coordinates of all four corners of that map, i.e. where exactly the map you have fits in in the global coordinate system. Then you simply calculate the position as an offset to those corners. This may be somewhat complicated if the projection system used is different. So, first of all, figure out what boundary coordinates your map has and what projection it's in. — deceze, Jan 06 '14 at 10:04
the map is Equirectangular projection you have idea with the math formula with it sir?? — webdev002, Jan 06 '14 at 23:48

Micromega · Accepted Answer · 2014-01-10T17:01:02.173

0

It's not so simple. You need to compute the map bounds and the delta of both axis, I.e. a factor. It's not very accurate but you can use the code and a bit of trial and error. For example if you use the same factor for both axis it looks weird and simply doesn't fit the map.

edited Jan 10 '14 at 17:01

answered Jan 07 '14 at 03:06

Micromega

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Ah.. any sample formula code? :( thanks – webdev002 Jan 07 '14 at 03:23
@webdev002:It works for me but you need to change it a bit:http://stackoverflow.com/questions/18838915/convert-lat-lon-to-pixel-coordinate. – Micromega Jan 07 '14 at 10:04
thanks a lot.. Where can i download and try your code sir?.. if it is fine with you.. – webdev002 Jan 09 '14 at 02:56
@webdev002:Can you elaborate? Is this homework? What do you mean "download"? – Micromega Jan 09 '14 at 07:12
i mean how can i try to run your code?.. just a complicated activity :( – webdev002 Jan 09 '14 at 08:01
@webdev002:You can look here:http://www.phpdevpad.de/geofence/. Then choose "jp". It should show Japan.Does it help? – Micromega Jan 09 '14 at 08:08
How can i get the source code of this sir?.. sorry if i ask to much :( – webdev002 Jan 10 '14 at 02:41
@webdev002:I want to show you a map projection.You can use the source code.You need to change it a bit. – Micromega Jan 10 '14 at 07:03
@webev002:There is source code and answer:http://stackoverflow.com/questions/18838915/convert-lat-lon-to-pixel-coordinate. – Micromega Jan 10 '14 at 07:09
@webdev002:You can also try this:http://stackoverflow.com/questions/10887692/php-map-projections. – Micromega Jan 10 '14 at 07:28

Convert long and lat to Coordinates on country only

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