Usualy this problem occurs where there is a bad data model.
Suppose you have only one file with duplicate value for your dimension, so the long/lat are duplicated also.
In apps using google maps, we use an expression for longitude like this Sum( round (256*pow(2,($(var_zoom)-1.....). The sum could create the problem.
2 solution :
- change sum with avg
- improve your data model keeping a table with only the locations.
Know that this is an old post, but I had the exact same problem and found the solution here :
So the problem is, that if you set the mapsize to e.g. 800x600 the scattechart thinks the scale is equal to the mapsize. But the dynamic picture from Google is maximum 600x600 for "free users", and therefore the bubbles are placed wrong compared to the dynamic image.
So follow the code from "pjohn" and your maps will look a lot better :-)
Kudos to pjohn : http://community.qlik.com/people/pjohn :-)