Dear Jody Garnett,
Yes this is working !!!! ... Thank you for all your help.
But I have some other issue, that is when I click on the image, I am able to
convert
the screen to map coordinate and bring it to center of the map in the image
along with some zoomin ability.
But when I now click on the second image, I am not getting the center of the
map properly,
I guess the reason for this is mapExtent is changing and also zoomfactor is
changing.
for this reason I created the following two methods, to keep the latest
envelope (Map extent)
in the session.
that is., one which runs when zoomin operation and other for zoomout
operation:
public void setMapEnvelopeZoomin(Point2D worldcenterpoint){
Envelope env = this.mapContext.getAreaOfInterest();
double x = worldcenterpoint.getX();
double y = worldcenterpoint.getY();
double minx = 0.0;
double miny = 0.0;
double maxx = 0.0;
double maxy = 0.0;
double width = env.getWidth();
double height = env.getHeight();
minx = (x) - ((width/2) * this.getZoomFactor());
maxx = (x) + ((width/2) * this.getZoomFactor());
miny = (y) - ((height/2) * this.getZoomFactor());
maxy = (y) + ((height/2) * this.getZoomFactor());
System.out.println("zoomin minx=" + minx + ", miny=" + miny + ", maxx=" +
maxx + ", maxy=" + maxy);
if((minx != Double.NaN) || (miny != Double.NaN) || (maxx != Double.NaN) ||
(maxy != Double.NaN)) {
Envelope enew = new Envelope(minx, maxx, miny, maxy);
this.mapContext.setAreaOfInterest(enew);
}
}
public void setMapEnvelopeZoomout(Point2D worldcenterpoint){
Envelope env = this.mapContext.getAreaOfInterest();
double x = worldcenterpoint.getX();
double y = worldcenterpoint.getY();
double minx = 0.0;
double miny = 0.0;
double maxx = 0.0;
double maxy = 0.0;
double width = env.getWidth();
double height = env.getHeight();
minx = (x) - ((width *2) / this.getZoomFactor());
maxx = (x) + ((width *2) / this.getZoomFactor());
miny = (y) - ((height * 2) / this.getZoomFactor());
maxy = (y) + ((height * 2) / this.getZoomFactor());
System.out.println("zoomout minx=" + minx + ", miny=" + miny + ", maxx=" +
maxx + ", maxy=" + maxy);
if((minx != Double.NaN) || (miny != Double.NaN) || (maxx != Double.NaN) ||
(maxy != Double.NaN)) {
Envelope enew = new Envelope(minx, maxx, miny, maxy);
this.mapContext.setAreaOfInterest(enew);
}
But this function, works good for first few zoomins and zoomouts, but
sometimes, it gets -values and then fails...
Do you know, what mistake I am making in these funtions.....
If this is not the right method, then please let me know how to change the
mapextent (Envelope) when the
center and zoomfactor of the map changes..
Once again thank you for all
Regards
Govardhan
----- Original Message -----
From: "Jody Garnett" <[EMAIL PROTECTED]>
To: "Govardhan" <[EMAIL PROTECTED]>;
<[email protected]>
Sent: Tuesday, November 28, 2006 11:38 PM
Subject: Re: [Geotools-gt2-users] NEED TO convert the image coordinate to
Map coordinate
> HI Mr Govardhan:
>
> I understand that sample code is *needed* by a library - and you are
> correct in asking on the user list: in talking to Jesse he told me of a
> Render Utilities class that helps with transforms ....
>
> http://javadoc.geotools.fr/2.2/org/geotools/renderer/lite/RendererUtilities.html
>
> I have not looked at this class before either -- their is a
> worldToScreenTransform( mapExtent, paintArea) method that returns a
> Transform.
>
> AffineTransform world2screen = RendererUtilities.worldToScreenTransform(
> mapExtent, imageArea );
>
> From there you can call transform.createInverse() to get a transform
> going from screen to world ...
>
> AffineTransform screen2world = world2screen.createInverse();
>
> And then finally we need to take your points x and y and transform them:
>
> Point2D screen = new Point2D( x, y );
> Point2D world = screen2world.transform( ptSrc, null );
>
> This world point should be something useful in your data set. The
> mapExtent you will need to figure out from the code you used to generate
> the image, and the imageArea is the size of your image I expect.
>
> Give that a go - and get back to me; if it still does not work I will
> try and spend my coffee break on it.
> Jody
>> Dear Jody Garnett,
>> Thank you for the info, but I am very new to this kind of operation, I am
>> having tough time to
>> do this, inverse, can I get some sample code which can give me some push
>> to do the same.
>>
>>
>> Best Regards
>> Govardhan
>>
>>
>> ----- Original Message ----- From: "Jody Garnett"
>> <[EMAIL PROTECTED]>
>> To: "Govardhan" <[EMAIL PROTECTED]>
>> Cc: <[email protected]>
>> Sent: Sunday, November 26, 2006 7:10 AM
>> Subject: Re: [Geotools-gt2-users] NEED TO convert the image coordinate to
>> Map coordinate
>>
>>
>>> Trying to think - you got an affine transform.
>>>
>>> So you need to get the transform.inverse() and then use that to
>>> "back-project" the screen coordinate - what pops out should be in the
>>> Map coordinate system.
>>>
>>> Cheers,
>>> Jody
>>>> Hi All,
>>>> I am using streamingRenderer and created a jpg image of the Map,
>>>> now I am able to bring this map on the browser.
>>>> When I click on the Map, I get x,y any where between 0-640 (w) and
>>>> 0-480 (h), but now I need to convert this clicked point
>>>> to Map coordinate point, so that I can bring that clicked point to the
>>>> center of the map in my next image generation.
>>>> PLEASE Help me in doing this, I am having really very hard time to
>>>> achieve this.
>>>> I am able to zoomin and zoomout by changing the zoomfactor in
>>>> AffineTransform , but Not able to bring the center of the map
>>>> where user is click on the image.
>>>> Best Regards
>>>> Govardhan
>>>> Congruence Software Solutions Pvt Ltd
>>>> KusumPrakash Arcade, site no:9
>>>> 1st Main, SanjayNagar
>>>> Bangalore-94
>>>> (O) 001-91-41674163
>>>> (V) 678-248-2437
>>>> (M) 001-91-9980036996
>>>> http://www.congruence.co.in
>>>> ------------------------------------------------------------------------
>>>>
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>>>
>>
>>
>
>
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