<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial, helvetica, sans-serif;font-size:10pt"><div style="font-family: arial,helvetica,sans-serif; font-size: 10pt;">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. <br><br>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.<br><br>Curtis<br><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;">----- Original Message ----<br>From: Alex Chew <alex_chew@163.com><br>To: PostGIS Users Discussion <postgis-users@postgis.refractions.net><br>Sent: Monday, November
27, 2006 10:39:47 PM<br>Subject: Re: Re: [postgis-users] How can i get accurate world coordinate (WGS84)with mouse click?<br><br>
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<div><font face="宋体" size="2"><font face="宋体" size="2">Hi，Markus</font></font></div>
<div><font face="宋体" size="2"><font face="宋体" size="2"> Can you read image
followed?</font></font></div>
<div><font face="宋体" size="2"><font face="宋体" size="2">All red points are mouse clicked
point in Screen Coordinate and green points are in World
Coordinate.</font></font></div>
<div><font face="宋体" size="2"><font face="宋体" size="2">I am still got know idea
about why this happened. </font></font></div>
<div><font face="宋体" size="2"><font face="宋体" size="2">X is accurate while Y is
error.</font></font></div>
<div> </div>
<div><font face="宋体" size="2">Would you please show me the way to a
resolution?</font></div>
<div><font face="宋体" size="2">Thanks</font></div>
<div><font face="宋体" size="2">Alex </font></div>
<div><font face="宋体" size="2"> </font></div>
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