How to calculate x and y pixel width for world file?

[Kralidis,Tom [Burlington]]

PS -- y_pixel_width should be:
 
y_pixel_width = (abs((maxy - miny)) / height) * -1

> -----Original Message-----
> From: Kralidis,Tom [Burlington] 
> Sent: 21 August, 2006 11:20 AM
> To: 'Paul Maine(ATS)'; 'MAPSERVER-USERS at LISTS.UMN.EDU'
> Subject: RE: [UMN_MAPSERVER-USERS] How to calculate x and y 
> pixel width for world file?
> 
> 
> Something like this would do the trick:
> 
> x_pixel_width = abs((maxx - minx)) / width y_pixel_width = 
> abs((maxy - miny)) / height
> 
> ..Tom
> 
> 
> > -----Original Message-----
> > From: UMN MapServer Users List
> > [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On Behalf Of Paul Maine(ATS)
> > Sent: 21 August, 2006 11:11 AM
> > To: MAPSERVER-USERS at LISTS.UMN.EDU
> > Subject: [UMN_MAPSERVER-USERS] How to calculate x and y pixel width 
> > for world file?
> > 
> > I am using ESRI SOAP webservices to obtain a map for use with 
> > Mapserver. I know that in order to use the map that is 
> formatted as a 
> > gif - that I need to create world file.
> > 
> > Since I know the extent of the map image - do I need to use a world 
> > file?
> > 
> > See the following for info on how to create a world file:
> > 
> > http://mapserver.gis.umn.edu/docs/howto/raster_data/#georefere
> > nce-with-world
> > 
> > 
> > How can I obtain the x and y pixel widths from the following 
> > information that is returned from the web service? I am 
> creating the 
> > map as an 800 x 800 pixel gif file.
> > 
> > Here is the relevant information that is returned by the webservice:
> > 
> > 
> > <n2:MapImageInfo xsi:type='n2:MapImageInfo'> ...
> >       <mapArea xsi:type='n2:MapArea'>
> > ...
> >        <extent xsi:type='n3:Envelope'>
> > ...        <projection xsi:type='xsd:string'>4326</projection>
> > ...
> >         <maxX xsi:type='xsd:double'>-117.10667</maxX>
> >         <maxY xsi:type='xsd:double'>34.13056</maxY>
> >         <minX xsi:type='xsd:double'>-117.25667</minX>
> >         <minY xsi:type='xsd:double'>33.98056</minY>
> > 
> > 
> > 
> > Thank You
> >