Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

I am experiencing a small screen space offset when using a WMS layer (origin is GeoServer 2.1.4). Looking at the requests from QGIS (1.7.4) to my GeoServer I realised that the aspect ratio between the WIDTH/HEIGHT and the BBOX is different. Calculating the aspect difference back into screen space gives a difference of ~1 pixel - I wonder if it could be the reason for my offset?

Due to devices with non-square pixels it makes sense that the aspect ratio can differ.

But what is the reason for QGIS not enforcing equality between the aspect ratios?

share|improve this question
1  
rounding error? –  iant Jun 28 '12 at 12:44
    
Where in the proces do you propose the rounding error? –  Chau Jun 28 '12 at 12:58
    
probably in the bounding box as that is a floating point calculation as opposed to screen size (integer pixel count)? –  iant Jun 28 '12 at 14:21
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.