# Re: [OpenMap Users] Rotation of map in Lambert projection

From: Rob Ratcliff <rratcliff_at_ticom-geo.com>
Date: Tue, 13 Feb 2007 11:00:13 -0600

It looks like Chris's version of the LambertConformal works much better!
Thanks Chris!
(I'm testing it out now on the imagery data server.)

--------------------------------------------- Previous Posting
------------------------------------

Speaking of the Lambert projection, shouldn't one be able to use this
projection to convert from State-plane coordinates to Lat/Lon and
vice-versa?

I tried it using this approach:

LatLonPoint center = new LatLonPoint(30.1167,-100.3333);
LambertConformal lambert = new
LambertConformal(center,1000000.0f, 500,500,
-100.3333333333333,
30.11666666666667, 31.88333333333333,
29.66666666666667,700000,3000000);
Point2D pt = new Point2D.Double();
lambert.LLToWorld(30.015643,-98.179725, pt);
System.out.println(pt.toString());
and get this:
Point2D.Double[0.039672363330592424, 1.6755878139863907]

I should be getting numbers for easting and northing in the hundreds of
thousands to millions.

Does anybody know how to transform these numbers into Easting and
Northing in meters or feet?

(I need to be able to convert back and forth in order to display some
imagery data from a server that expects the bounding box to be specified
in the state-plane coordinate system.)

Thanks

Rob

p.s. Here is the definition of the SP coordinate system I'm using:

/*
*

*
can_1983",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]

*
],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["False_Easting",700000],PARAMETER["False_Northing",3000000],

*
PARAMETER["Central_Meridian",-100.3333333333333],PARAMETER["Standard_Parallel_1",30.11666666666667],PARAMETE

*
R["Standard_Parallel_2",31.88333333333333],PARAMETER["Latitude_Of_Origin",29.66666666666667],UNIT["Meter",1]]

*
http://www.cnr.colostate.edu/class_info/nr502/lg3/datums_coordinates/spcs.html

* lines.append("<ENVELOPE minx='3112576.5229230225'
miny='10112154.75590226' " +
* "maxx='3112956.9819749305' maxy='10112501.491367795' " +
* "name='Initial_Extent' />");
*/

Chris van Lith wrote:
> Hi Frédéric,
>
> Enclosed you will find my update of the openmap projection. I also
> found some strange things and thus changed the projection to my needs.
> it has been used for belgium. maybe it is useful for you.
>
> Met vriendelijke groeten
> Chris van Lith
>
> ------------------------------------------------------------------------
> *From:* Frédéric PRACA [mailto:frederic.praca_at_freebsd-fr.org]
> *To:* openmap-users_at_bbn.com
> *Sent:* Mon, 12 Feb 2007 16:59:40 +0100
> *Subject:* [OpenMap Users] Rotation of map in Lambert projection
>
> Hello,
> I try to display a LambertConformal raster map on OpenMap but I am
> not able to
> change the meridian used to display the world layer. I tried to
> change the
> getUpperLeft and getLowerRight code to this :
> return new LatLonPoint(90.0, -180.0 + centralMeridian);
> and return new LatLonPoint(-90.0, 180.0 + centralMeridian);
> respectively.
> I expected the world map to rotate in order to have my
> centralMeridian in a
> vertical way but the world layer stays with the meridian 0° vertical.
>
> Do you have any clue to change this ?
>
> Regards,
> Fred
>
> --
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Received on Tue Feb 13 2007 - 13:08:44 EST

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