[mapserver-users] Re: shade a county

[Mark Brooks]

I figured it out.  It was actually pretty easy.  For reference to others 
who might need to do this also, I'll post my methodology.  I also have 
one outstanding question at the end...

Mapscript snippet looks like this:

// Make a new point object
$cnty_layer = $map->getLayerByName('cnty');
$my_point = ms_newpointObj();
$my_point->setXY($lon,$lat);

// Run a point query on the county layer.
// layer must have a class with a LAYER TEMPLATE value
if ($cnty_layer->queryByPoint($my_point,MS_SINGLE,1)==MS_SUCCESS){
    $cnty_result = $cnty_layer->getResult(0);  // Get the result
    $cnty_layer->open();    // Open layer for use with getShape()
 
$cnty_shape=$cnty_layer->getShape($cnty_result->tileindex,$cnty_result->shapeindex); 


    // Draw the shape onto the shaded county layer
    $cnty_shade = $map->getLayerByName('shade_red');
    $cnty_shape->draw($map, $cnty_shade, $image);
}


Mapfile snippet that goes along with the above looks like this:

LAYER
    NAME shade_red
    TYPE POLYGON
    STATUS ON
    TRANSPARENCY 50   # use OPACITY in mapserver v5
    CLASS
         NAME "Red County"
         COLOR 187 0 0
    END
END


Notice the transparency in the layer above.  I'm still on mapserver 4.x. 
  The problem is that the layer doesn't draw with any transparency, no 
matter what I put as the value.  Any ideas?

Mark


Mark Brooks wrote:
> I have a shapefile of type polygon of all counties in the United States. 
>  Given a latitude/longitude point, I want to shade/hatch the county that 
> it's in.  I'm not sure of the best way to do this.  Any suggestions?  
> I'm working with PHP Mapscript by the way.
> 
> Mark