[mapserver-users] Image Maps

[Antti.Roppola at brs.gov.au]

How about rendering a view of the Shapefile and using the RGB values
as a key to generate the Image map?

Use something like imlib inside PHP to create an interim image using
your region as a class-item... This would probably hit the filesystem
less than the approach you are currently using, plus the rendered image
would never have more cases to consider than the number of pixels in it.

Basically sample down the detailed data before you start processing.

Antti

-----Original Message-----
From: Manuel Marichal Pérez [mailto:marichalperez at yahoo.es]
Sent: Friday, 2 August 2002 12:01 AM
To: Lista (MapServer)
Subject: [mapserver-users] Image Maps



	Hi, all. Image maps are a commonly question treated in Mapserver list.
	The solution suggested by MapServer experts is to use Mapscript to read
	the shapes and then build up a image map. If your application uses a
	java viewer (such us ROSA or other) you can build the map using XML (for
	example) and then read it from Java.

	Ok. I wrote a PHP/Mapscript function that read the DBF file and extract
	the polygons. Each polygon is assigned a label which is extracted from a
	column of the DBF itself. With this, I make an XML file including the
	map and ROSA read it to manage the "MouseOver" method. This idea works
	fine:

	http://www.buscamap.com/simpletest/index.html

	The problem here is the layer which the image map is build for. If the
	layer contains very much polygons, this method take a long time to build
	the image map. My question is: it is possible to reduce this time?.

	- MapServer is unable to make image maps itself (correct me if not, please)

	- If I include a clipping method in the function, I will obtain smaller
	  XML files, but the time is not reduced because if I want to know which
	  polygons fall in the view and which fall out of it I still have to read
	  its coordinates to know it.

	- I suppose indexes (shptree) don't help at all because the polygons are
	  read in order to be treated and then, index are unuseful here.

	:(

	What can I do if I need image maps in my application and the layer which I
	need for contains several polygons?. Any ideas?.

	Thanks in advance,
	Manuel Marichal Pérez
	marichalperez at yahoo.es






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