[mapguide-users] Precision problem viewing map

[Stefan Dalakov]

Hi all,
I am facing a strange and unexpected problem regarding precision of map 
and coordinates display. I see that my data is not displayed on the 
exact place - there is a shift in Y coordinate. I have a raster layer 
with bounding rectangle
Xmin=..., Ymin=7070400, Xmax=.... Ymax=7071600. But when I move the 
mouse pointer at the lower left corner I see Y=7070320 (at scale 1:2000 
let say) or similar value, and the difference depends on the scale. If I 
zoom down, the difference changes, and at scales close to 1:50 it is ok. 
The situation is similar at the upper right corner. I observe exactly 
the same effect with all other layers.
I wouldn't care too much about this - even if there is a shift, all 
layers are shifted equally, but when I digitize a polygon it is also 
shifted. Imagine I digitize a polygon to follow a feature on the raster 
image, coordinates are recorded , the feature is added to data source, 
but when it is added, due to this shift it appears not where it has been 
digitized, but shifted.
I guess you did not understand anything of this, but you can visit

http://www.bgmapguide.com:8008/mapguide/rakvag/main.php

click on "draw a new suggestion" and try to digitize 2 adjacent polygons 
- you will see them overlap
Please be gentle to the server - it is an old tired horse.
And to save some time - all layers and the map are in the same 
coordinate system.
This effect is not depending on the browser (tested with FFox 2 & 3, 
Safari and IE) and is not depending on the screen resolution


Best regards : Stefan Dalakov