[mapserver-users] Reporting lat/long from projected map units

[Bistrais, Bob]

I have it functioning now, but the input and output values are the same,
I'm not seeing any conversion.

 

________________________________

From: Milo van der Linden [mailto:milo at dogodigi.net] 
Sent: Thursday, January 13, 2011 11:09 AM
To: Bistrais, Bob
Cc: mapserver-users
Subject: Re: [mapserver-users] Reporting lat/long from projected map
units

 

Mmm, that shouldn't be to hard. Let me try;

var source = new Proj4js.Proj('EPSG:YOUR_UTM_EPSGCODE');

var dest = new Proj4js.Proj('EPSG:4326'); . . .



// transforming point coordinates

var p = new Proj4js.Point(YOUR_UTM_X,YOUR_UTM_Y);




Proj4js.transform(source, dest, p);     



alert(p.x); //WILL ALERT YOUR NEW LON

alert(p.y); //WILL ALERT YOUR NEW LAT

 

2011/1/13 Bistrais, Bob <Bob.Bistrais at maine.gov>

I downloaded the code and am looking at the Wiki.  I don't see anything
to input screen or UTM coords.  Is it in the code somewhere? 

 

________________________________

From: Milo van der Linden [mailto:milo at dogodigi.net] 
Sent: Wednesday, January 12, 2011 12:44 PM
To: mapserver-users


Subject: Re: [mapserver-users] Reporting lat/long from projected map
units

 

(Sorry, my last posts went straight to you by accident, I prefer to stay
on the list, but gmail for applications not always agrees with me)

proj4js has project pages including documentation on the OSGeo wiki. The
userguide is here:

http://trac.osgeo.org/proj4js/wiki/UserGuide

and it immediately explains what you want

2011/1/12 Bistrais, Bob <Bob.Bistrais at maine.gov>

Yes, I can get UTM coordinates back.  Can you elaborate a bit on
proj4js?  I'm not familiar with that.

 

________________________________

From: Milo van der Linden [mailto:milo at dogodigi.net] 
Sent: Wednesday, January 12, 2011 11:10 AM


To: Bistrais, Bob
Subject: Re: [mapserver-users] Reporting lat/long from projected map
units

 

Well then one question remains:

Are you able to convert screen coords to UTM capturing an onclick event?
Because then all you need to do is enhance it with proj4js

2011/1/12 Bistrais, Bob <Bob.Bistrais at maine.gov>

Yes, a web mapping application.  Not using Open Layers.  We are using
PHP-Mapscript/HTML/JavaScript.  All queryable data is in shapefiles,
again, all of these are in UTM.

 

________________________________

From: Milo van der Linden [mailto:milo at dogodigi.net] 
Sent: Wednesday, January 12, 2011 11:03 AM
To: Bistrais, Bob


Subject: Re: [mapserver-users] Reporting lat/long from projected map
units

 

Are you talking bout a web-app? Do you use a client like OpenLayers?
What programming language(s) do you use? Is your datasource a database?
Like postgis?



If you can get UTM coordinates from the mouseclick, the next best option
(in my opinion) would be to use proj4js:

http://proj4js.org/

Simply embed the js-library ad an event for mouse handling and convert:
screen->utm->4326. 

2011/1/12 Bistrais, Bob <Bob.Bistrais at maine.gov>

This should be fairly straightforward, but I was wondering what is the
easiest and quickest way to convert coordinates on the fly.  All my data
is in UTM coordinates.  I want to report coordinates to the screen in
Lat/Long.  Changing the projections on the map files to lat/long
(EPSG:4326) is not an option, as this will cause problems elsewhere.  So
what I want to do is take point coordinates, either from a mouse click
or from UTM coordinates, project to lat/long, which will be reported in
a result window.  What is the quickest way to do this?


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