shrug-l: RE: Lat/Long(decimal degrees) to Meters without Geometry service

Janelle Brown Janelle.Brown at citizensfla.com
Thu May 26 15:03:25 EDT 2011


Thanks everyone for all the great suggestions. 

 

The solution came from Scott Taylor at Division of Forestry. He
suggested I use the equatorial radius instead of the polar radius and
now the point is plotting exactly where it should. Thanks Scott!!

 

 

Janelle Brown

GIS Analyst, Corporate Analytics

Citizens Property Insurance Corporation

-------------------------------------------------------

ofc. 850.521.8373   |   cell 850.879.2374

 

 

From: Janelle Brown 
Sent: Thursday, May 26, 2011 2:02 PM
To: 'shrug-l at lists.dep.state.fl.us'
Subject: Lat/Long(decimal degrees) to Meters without Geometry service

 

Hello,

 

Does anyone have a javascript code that can convert decimal degrees
(wkid: 4326) points to meters (wkid: 3857)? I am not able to use the
geometry service for a number of reasons, so I believe the only way to
do this would be to convert the points mathematically. This is what I
have so far and it's kinda working (I'm off about 20-25 miles), but I'm
pretty sure there is some tweaking needed in the equations. If anyone
has any ideas or has already written some javascript code for this, I'd
be very grateful!

 

       function addPointToMap() {

            var xMin,yMin,xMax,yMax;

            var lon ,lat;

            var DEG_TO_RAD = 0.017453292519943296;                

            var PI = 3.14159267;

            var NUM = 6356752.3142;

            

            lon = -84.286616;

            lat = 30.437574;

      

            //Limit to World

            if(lat<=-90)lat=-90;

            if(lat>=90)lat=90;

            if(lon<=-180)lon=-180;

            if(lon>=180)lon=180;

            

var Y = Math.round(NUM * Math.log( Math.tan( ((lat * DEG_TO_RAD) +
(PI/2)) / 2 ) ));

            var X = Math.round(NUM * (lon * DEG_TO_RAD));

 

 

Thank you in advance!

 

Janelle Brown

GIS Analyst, Corporate Analytics

Citizens Property Insurance Corporation

-------------------------------------------------------

ofc. 850.521.8373   |   cell 850.879.2374

 

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