[Mapserver-users] Zoom error with Python

[Sven Jacobi]

Hello,


I'm using Mapserver inside Zope and I'm writing External methods 

(Python Scripts) to call the C-libraries.

I receive errors when I try to zoom in a map, but when using the same code

for zooming out or panning, it works?!

Below there's the small part of code responsible for that. I have no idea

where this might come from...

 

Any help?


Thanks,


Sven


The error is as follows:

Traceback (most recent call last):

  File "/home/jacobi/Funkland/Zope-2.5.1b2-src/Extensions/mapserv.py", line 
79, in ?

    drawmap(['1','5'], '3', '1', '200', '200')

  File "/home/jacobi/Funkland/Zope-2.5.1b2-src/Extensions/mapserv.py", line 
45, in drawmap

    myimage=mymap.draw()

  File "/home/jacobi/Funkland/site-packages/MapScript.py", line 1941, in draw

    val = MapScriptc.mapObj_draw(self.this)

RuntimeError: msSearchDiskTree(): Unable to access file.

 

Exception exceptions.RuntimeError: 'msSearchDiskTree(): Unable to access file. 
\n' in <method mapObjPtr.__del__ of mapObj instance at f155c> ignored</italic>

--------------------------------------------------------------------------

def drawmap(layer, zoomfactor, zoomdirection, imgx, imgy):

 mymap = mapObj("/home/jacobi/public_html/Funkland/brenschel2.map")

 mymap.prepareImage()

 mymap.width=600

 mymap.height=400 


#----- Zooming und Panning

 zoomfac = int(zoomfactor)

 zoomdir = int(zoomdirection)

 xi = int(imgx) 

 yi = int(imgy)


 #Zoomfaktor auslesen

 if (zoomdir == 0):

  zoom = 1

  print 'zoom0'

 elif (zoomdir == -1):

  zoom = 1.0/zoomfac

  print 'zoom-1' 

 elif (zoomdir == 1):

  zoom = zoomfac

  print 'zoom1'

  print zoom


 #Berechnung der "Zellengroesse"

 cx = (mymap.extent.maxx - mymap.extent.minx)/mymap.width

 cy = (mymap.extent.maxy - mymap.extent.miny)/mymap.height


 #Berechnung der Mapkoordinaten aus den Imagekoordinaten

 x = mymap.extent.minx + cx * xi 

 y = mymap.extent.maxy - cy * yi

 

 #Berechnung des neuen Extends

 mymap.extent.minx = x - 0.5 * ((mymap.extent.maxx-mymap.extent.minx) / zoom) 

 mymap.extent.miny = y - 0.5 * ((mymap.extent.maxy-mymap.extent.miny) / zoom)

 mymap.extent.maxx = x + 0.5 * ((mymap.extent.maxx-mymap.extent.minx) / zoom)

 mymap.extent.maxy = y + 0.5 * ((mymap.extent.maxy-mymap.extent.miny) / zoom)

 #print mymap.extent.minx


#----- END Zooming und Panning


 myimage=mymap.draw()


#----- Layeroptionen

 if (len(layer)!=1):

	for i in range (0,len(layer)):

                #print i

		if (layer[i]=='1'):

			layer0 = mymap.getLayer(0)

			layer0.status = 1

 			layer0.draw(mymap, myimage)

		elif (layer[i]=='2'):

			layer1 = mymap.getLayer(1)

			layer1.status = 1

 			layer1.draw(mymap, myimage)

		elif (layer[i]=='3'):

			layer2 = mymap.getLayer(2)

			layer2.status = 1

 			layer2.draw(mymap, myimage)

		elif (layer[i]=='4'):

			layer3 = mymap.getLayer(3)

			layer3.status = 1

 			layer3.draw(mymap, myimage)

		elif (layer[i]=='5'):

			layer4 = mymap.getLayer(4)

			layer4.status = 1

 			layer4.draw(mymap, myimage)


#----- END Layeroptionen


 #myimage=mymap.draw()

 mymap.drawLabelCache(myimage)

 out = myimage.saveImage("brenschel.png",MS_PNG,50,0,50)

 return out 


drawmap(['1','5'], '3', '1', '200', '200')</smaller>