Highlight Features

[Armin Burger]

Rob,

the easiest way would be using the querymap function like
...
// Execute a query (here an attribute query)
$queryString = "('[subdivname]' = '$sSubDivsion')";
$your_layer->queryByAttributes('subdivname', $queryString, MS_MULTIPLE);

// Draw map
$mapImg = $map->drawQuery();  // instead of $map->draw()
...

You can specify colors for highlighting in a QUERYMAP tag in the map file.


A more flexible solution (but more complex) is to add an additional
layer containing only the selected feature and add this layer to the map 
on top of the base layer:
1) create a new layer
2) get the shape index of the feature to be drawn and then add
    it to the new layer
3) define the styles/colors etc for this feature

If you're interested I can send you some code for this latter version.

Armin

Rob Sosnowski wrote:
> Hello All,
> 
> Using PHP/Mapscript 4.4.  Trying to highlight feature in polygon layer,
> such as subdivisions.  I use:
> 
>    $layer->setFilter("");
>    $sFilter = "('[subdivname]' = '$sSubDivsion')";
>    $layer->setFilter($sFilter);
> 
> PROBLEM: ONLY THAT SPECIFIC FEATURE IS DRAWN.  If I use:
> 
>    $sFilter = "('[subdivname]' != '$sSubDivsion')";
> 
> PROBLEM: ALL FEATURES DRAWN EXCEPT ONE OF INTEREST, WHICH IS OK EXCEPT IN
> PLACES WHERE THE BOUNDARY OF THE FEATURE OF INTEREST HAS NO SURROUNDING
> POLYGONS.  WHEN THIS IS THE CASE, THE BOUNDARY OF FEATURE IS NOT SHOWN.
> 
> 
> QUESTION: HOW DO I DRAW ALL FEATURES WITHIN POLYGON LAYER AND ALSO
> HIGHLIGHT THE FEATURE(S) OF INTEREST IN A DIFFERENT COLOR
> 
> Thanks, Rob
> 
>