map->scale

[Tim Schaub]

>    I'm trying to migrate a CGI application of map server to a 
> PHPMapScript driven one, and in the former exists the scale 
> environment variable but in the other, and according to the 
> documentation, there isn't, and the app should set it.

If you have a reference to your map in PHP (say $theMap), you can get the map scale from $theMap->scale (see http://mapserver.gis.umn.edu/docs/reference/phpmapscript-class/classes/mapobj)

The map scale is updated after a drawMap() or preparequery().
 
If you really wanted to calculate it yourself, I'm guessing you can do something like this:

function getScale($theMap) {
  if($theMap->units == MS_PIXELS) {
    return 1;
  }

  $inchesPerMapUnit = array(
    MS_INCHES => 1,
    MS_FEET => 12,
    MS_MILES => 63360,
    MS_METERS => 39.370079,
    MS_KILOMETERS => 39370.07874,
    MS_DD => 4374720);

  $mapUnitWidth = $theMap->extent->maxx - $theMap->extent->minx;
  $mapPixelWidth = $theMap->width;

  // assuming the map is wider than zero pixels
  return $inchesPerMapUnit[$theMap->units] * $mapUnitWidth * $theMap->resolution / $mapPixelWidth;
}

No guarantees that that is how they do it (I didn't test it).  But it seems to me like it should work.

Tim Schaub
http://www.commenspace.org


>    Thanks in advance,
> 
> Diego.
> 
> P.S.: excuse my poor english
> 
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