[postgis-users] How can i get accurate world coordinate (WGS84)with mouse click?

Curtis W. Ruck ruckc at yahoo.com
Mon Nov 27 21:31:56 PST 2006

>From what I see your Y (latitude) scaling in your translation from screenpoint to coordinate point application isn't accounting for latitudes further away from the equator.  

Inside your application you should have something that calculates the translation for longitude properly (longitude appears fine), so replicate the scaling that you are using for your longitude for your latitude also, don't reuse the scaling variable in your latitude math from your longitude math.


----- Original Message ----
From: Alex Chew <alex_chew at 163.com>
To: PostGIS Users Discussion <postgis-users at postgis.refractions.net>
Sent: Monday, November 27, 2006 10:39:47 PM
Subject: Re: Re: [postgis-users] How can i get accurate world coordinate (WGS84)with mouse click?



   Can you read image 


All red points are mouse clicked 

point in Screen Coordinate and green points are in World 


I am still got know idea 

about why this happened. 

X is accurate while Y is 



Would you please show me the way to a 





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