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NAME:
     Geo::Heatmap
     
     overlay a density map (aka heatmap) over googlemaps

     see example here

     http://www.trust-box.at//dev/gm/GoogleMapsHeatmap/www/GoogleMapsHeatmap.html

GET CODE
    https://github.com/MarkHofstetter/GoogleMapsHeatmap

SYNOPSIS
    Create a Heatmap layer for GoogleMaps

    my $ghm = Geo::Heatmap->new();
    $ghm->palette('palette.store');
    $ghm->zoom_scale( {
      1 => 298983,
      2 => 177127,
      3 => 104949,
      4 => 90185,
      5 => 70338,
      6 => 37742,
      7 => 28157,
      8 => 12541,
      9 => 3662,
      10 => 1275,
      11 => 417,
      12 => 130,
      13 => 41,
      14 => 18,
      15 => 10,
      16 => 6,
      17 => 2,
      18 => 0,
    } );
  
    $ghm->cache($cache);
    $ghm->return_points( \&get_points );
    my $image = $ghm->tile($tile);


    You need a color palette (one is included) to encode values to colors, in Storable Format as an arrayref of arrayrefs eg
      [50] = [34, 45, 56]
    which means that a normalized value of 50 would lead to an RGB color of 34% red , 45% blue, 56% green

    zoom_scale
      the maximum number of points for a given google zoom scale, you would be able to extract to values from the denisity log
      or derive them from your data in some cunning way

    cache 
      you need some caching for the tiles otherwise the map would be quite slow. Use a CHI object with the cache you like

    return_points
      is a function reference which expects a single hashref as a parameter which defines two LAT/LONG points to get all
      data points within this box
      $r->{LATN}, $r->{LNGW}), $r->{LATS}, $r->{LNGE}
      the function has to return an arrayref of arrayrefs of the points within the box

    tile 
      returns the rendered image