4.10 GEOS Fuctions with PHP Mapscipt

[Yewondwossen Assefa]

Chris,

  I have actually tested the within function yesterday with 2 shape 
files using the latest mapserver and I was getting the results as 
expected. If you can provide me with a small data set that I can use to 
do some tests,  I can look into it.

Later,

CamKhmer wrote:
> Hi Yewondwossen,
> 
> Thanks for your feedback, as you said districts are within provinces. I
> tried switching the statement and running it through an if statement like
> so:
> 
> if($oDistShape->within($oProvShape)) {
>       echo "true";
> }
> else {
>       echo "false";
> }
> 
> This just returned false on every attempt as the argument isn't recieving
> any value, true or false. I really don't think this is a syntax issue. The
> method just won't return a result if the shapes are from serperate shape
> files, is this how it is supposed to work or is this an issue with the
> Mapscript implimention?
> 
> Regards,
> 
> Chris
> 
> 
> Yewondwossen Assefa wrote:
> 
>>Chris,
>>
>>  The within function returns true or false so tests should be done like 
>>this if ($oProvShape->within($oDistShape)) echo "1" else echo "0".  The 
>>blank page in your case simple means that the within function returned 
>>false.
>>
>>  Is it possible that the test you are doing is inversed? : by looking 
>>at the name of the layers, I am assuming that districts are inside 
>>provinces so a call $oProvShape->within($oDistShape) would return false 
>>and the $oDistShape->within($oProvShape); would return true.
>>
>>  I have checked the documentation of php mapscript and it was stated 
>>incorrectly leading to the confusion. It is now updated and reflects the 
>>correct syntax.
>>
>>  Let me know if that solves your problem.
>>
>>Best Regards,
>>
>>CamKhmer wrote:
>>
>>>Hi Steve,
>>>
>>>Thanks for your response. I am not receiving the response I was expecting
>>>from the shapeObj->within() method when I pass to it a shapeObj from a
>>>separate layer. I was expecting that GEOS would compare the geometry of
>>>shape A and shape B then determine whether one was within the other, if
>>>this
>>>was the case I thought that this method could take any valid shape object
>>>regardless of its source, but this appears not to be the case. Here's a
>>>thinned down version of what I'm trying to do (apologies for posting an
>>>elongated chunk of code up):
>>>
>>><?php
>>>$oMap = ms_newMapObj($szMapFile);
>>>
>>>function getShapeByName($oMap, $sLayerName, $sColumnName, $sShapeName){
>>>	$oLayer = $oMap->getLayerByName($sLayerName);
>>>	$oLayer->open();
>>>
>>>	//returns all the shapes in the layer
>>>	$status = $oLayer->whichShapes($oMap->extent);
>>>
>>>	//Loop through each of the shapes
>>>	while ($shape = $oLayer->nextShape()) 
>>>		   {
>>>			   $shapeIndex = $shape->index;
>>>			   $oShape = $oLayer->getShape(-1,$shapeIndex);
>>>			   $sName = $oShape->values[$sColumnName];
>>>
>>>			   //return if we have the shape we're after
>>>			   if($sName == $sShapeName) {
>>>			   		return $oShape;
>>>			   }		   		   
>>>		   }
>>>	return null; 	   
>>>	//$oLayer->close();	
>>>}
>>>
>>>//Get the province shape obj
>>>$oProvShape = getShapeByName($oMap, 'provinces_fill',
>>>'NAME','KHAMMUANE');
>>>
>>>//Get the district shape obj
>>>$oDistShape = getShapeByName($oMap, 'districts', 'NAME', 'NAKAI');
>>>
>>>//This shows I have the shape object so we know there are no problems
>>>prior
>>>to this
>>>print_r($oProvShape);
>>>print_r($oDistShape);
>>>
>>>//See if one shape is within another
>>>$inside = $oProvShape->within($oDistShape);
>>>
>>>//Should return true or false
>>>echo $inside;
>>>?>
>>>
>>>The above code just returns a blank screen, if I replace:
>>>
>>>$inside = $oProvShape->within($oDistShape);
>>>
>>>with:
>>>
>>>$inside = $oProvShape->within($oProvShape);
>>>
>>>It returns 1 as expected, which indicated to me that shape objects from
>>>one
>>>shape file can't be passed as an argument for the within() method of a
>>>shape
>>>object from a different shape file. Is this the case? If so is there any
>>>work around you can think of that doesn't involve dumping all the layers
>>>in
>>>a single shape file.
>>>
>>>Thanks for any input you can give me.
>>>
>>>Chris
>>>
>>>
>>>
>>>Steve Lime wrote:
>>>
>>>
>>>>Chris: The GEOS operators work at the shapeObj level and have no
>>>>connection to 
>>>>parent layers (you can create shapeObj's without mapfiles).
>>>>
>>>>Are you seeing strange behavior?
>>>>
>>>>Steve
>>>>
>>>>
>>>>
>>>>>>>CamKhmer <chrisscrazydays at HOTMAIL.COM> 10/24/2006 7:27:14 AM >>>
>>>>
>>>>Hi Guys,
>>>>
>>>>I have just begun experimenting with the GEOS functions now available in
>>>>4.10 via mapscript and have a question.
>>>>
>>>>Can shape objects from layer object A be passed as arguments to shape
>>>>object
>>>>methods in layer object B? (Each layer has a separate shape file)
>>>>
>>>>I am trying to create a function that determines if shape A (district) is
>>>>within shape B (province), as stated above both layers are separate
> 
> layers
> 
>>>>in separate shape files.
>>>>
>>>>I know I have the objects needed as both can be output using print_r(), I
>>>>know the method is working as if I pass a shape object from the same
> 
> layer
> 
>>>>I
>>>>get the results as expected.
>>>>
>>>>Is it just the case that shape objects from different layers or shape
>>>>files
>>>>can’t be passed as objects to shapeObj methods? If so it there any
>>>>feasible
>>>>way around this or am I just going to have to put both districts and
>>>>provinces in the same layer and output them through class references?
>>>>
>>>>Thanks for your ideas,
>>>>
>>>>Chris
>>>>
>>>>-- 
>>>>View this message in context:
>>>>http://www.nabble.com/4.10-GEOS-Fuctions-with-PHP-Mapscipt-tf2500940.html#a6971770 
>>>>Sent from the Mapserver - User mailing list archive at Nabble.com.
>>>>
>>>>
>>>
>>>
>>
>>-- 
>>----------------------------------------------------------------
>>Assefa Yewondwossen
>>Software Analyst
>>
>>Email: assefa at dmsolutions.ca
>>http://www.dmsolutions.ca/
>>
>>Phone: (613) 565-5056 (ext 14)
>>Fax:   (613) 565-0925
>>----------------------------------------------------------------
>>
>>
> 
> 


-- 
----------------------------------------------------------------
Assefa Yewondwossen
Software Analyst

Email: assefa at dmsolutions.ca
http://www.dmsolutions.ca/

Phone: (613) 565-5056 (ext 14)
Fax:   (613) 565-0925
----------------------------------------------------------------