What to do with calculated coordinates?

[neveldo]

What to do with calculated coordinates?

[neveldo]

Hello ! I'm glad you appreciate jQuery Mapael.

I'm currently working on a tutorial for creating maps for jQuery mapael. It will be available very soon, with the release of mapael 1.0.0 ! Here is the part regarding the getCoords() function :

"If you want to go further with your map, you may want plot cities by latitude and longitude on it. We assume that the projection of your map is an equirectangular one.

With this projection, the algorithm to convert a latitude and a longitude to x and y coordinates is as simple as that :

x = xFactor + latitude + xOffset
y = yFactor * longitude + yOffset

You just have to found the proper values for xFactor, yFactor, xOffset and yoffset in order to be able to plot cities by latitude and longitude on your map.

To get the values of xFactor and xOffset, you just have to resolve an equation with two unknowns. Plot two points at the max left and the max right of your map with x and y coordinates. Go to Google Map in order to find the matching latitudes for these two points (Right clic > More info about this place on Google map) .

You can now find the values for xFactor and xOffset by resolving this equation (tedious way, there is a tool for that, see below ;-) ) :

x1 = xFactor + latitude1 + xOffset
x2 = xFactor + latitude2 + xOffset

Then, you have to do exactly the same thing to get the values of yFactor and yOffset.

You can use the getCoords() generator tool that will resolve equations and generate the getCoords() method for you !"

The getCoords() generator is available here : http://www.neveldo.fr/mapael/getcoords.php .

I hope it will help you !

[demogorgorn]

Thank you very much for your quick answer!
It's great that you've created automatic coordinates calculator! Thank you for thinking of users!

[neveldo]

You are welcome :) Feel free to contribute to 'mapael-maps' repository (https://github.com/neveldo/mapael-maps) by adding your brand new map !

[demogorgorn]

Of course I will contribute the new my to the mapael's repository after finishing it. It's a map of Commonwealth of Independent States. Neveldo, thank You very much!

[shahzadasaeed]

Hi Neveldo,

I am using this for one of my project. but i am confusing in Coordinates system that is How we can calculate X1, Y1??

Thanks

[neveldo]

Hi,

All the steps are explained in this tutorial : http://www.vincentbroute.fr/mapael/create-map.php , did you check it ?

[Indigo744]

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