# Formula for calculating "true" isometric tile row/number?

**URL:** <https://forum.kirupa.com/t/formula-for-calculating-true-isometric-tile-row-number/316345>\
**Category:** flash\
**Created:** [November 18, 2010, 10:30pm UTC](https://forum.kirupa.com/t/formula-for-calculating-true-isometric-tile-row-number/316345 "2010-11-18T22:30:44Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![pepeu](https://avatars.discourse-cdn.com/v4/letter/p/f04885/32.png) [@pepeu](https://forum.kirupa.com/u/pepeu)\
**Post date:** [November 18, 2010, 10:30pm UTC](https://forum.kirupa.com/t/formula-for-calculating-true-isometric-tile-row-number/316345/1 "2010-11-18T22:30:44Z")

</div>

Hi, I’m trying to do a isometric game, diamond shaped stage. And want to know how the formula for translating the mouse position over a tile into the correct row/column of it.

I position them with something like this:

```php
for (var i=0; i<=rows-1; i++) {
    for (var j=0; j<=columns-1; j++) {
        var tileName = "t_"+i+"_"+j;
        var tile:Tile = new Tile();
        tile.name=tileName;
        // logic to display the right frame of tiles and such, blablabla...
        
        tile.x=(j-i)*tileHeight;
        tile.y = (j+i)*tileHeight/2;

        gameArr.push(gameGrid.addChild(tile));
    }
}

```

Usually the tiles are half as high as their width. A classic 2:1 ratio. Then I could use the following formula for transforming mouse position to a tiles row/column:

```php
var column:int = mapSize-(((mouseY/ tileHeight) + (mouseX - (mapSize * tileHeight)) / tileWidth) - mapSize) *-1;

var row:int = mapSize-(((mouseY/ tileHeight) - (mouseX - (mapSize * tileHeight)) / tileWidth) -mapSize) *-1;

```

If the grid is 50 x 50, then mapSize is 50.

But I’m trying to do what I think is called “true” isometric. Where the angles are 60 120 60… eh, anywho, the height is slightly higher. My tiles for instance, are 15 x 8.3.

…So, any ideas on how the formula would look like? How do I translate the mouse position to the current tiles row and column it is over.

Just to be clear, my “north” is upper right side.  
Like this:  
[[0, 1, 2],  
[3, 4, 5],  
[6, 7, 8]]  
And then rotates clockwise 45 degrees.