RE: [OpenMap Users] Lat/Lon Visibility ?

Don,

Ok, cool...I just remember having that problem before with that
algorithm with lat/lons, or something related. In a different app
though.

Martin

-----Original Message-----
From: Don Dietrick [mailto:dietrick@bbn.com]
Sent: Tuesday, March 02, 2004 1:31 PM
To: Chapman, Martin
Cc: openmap-users@bbn.com; Sperlongano Brian M NPRI
Subject: Re: [OpenMap Users] Lat/Lon Visibility ?

Hi Martin,

The forward method gives you a window pixel location for the lat/lon
coordinate. The algorithm simply tests whether that point is in the
window space. The projection.forward() algorithm will take care of the
dateline, etc.

- Don

On Mar 2, 2004, at 3:23 PM, Chapman, Martin wrote:

> Don,
>
> You can fix that though if you test for when that occurs and then
> forward project the negative x (lon) values by adding 360 to each x
> value. Then the alogorithm works.
>
> Martin
>
> -----Original Message-----
> From: Don Dietrick [mailto:dietrick@bbn.com]
> Sent: Tuesday, March 02, 2004 12:57 PM
> To: Sperlongano Brian M NPRI
> Cc: openmap-users@bbn.com
> Subject: Re: [OpenMap Users] Lat/Lon Visibility ?
>
>
> Hi Brian,
>
> You can do something like
>
> boolean isVisible(Projection proj, float lat, float lon) {
>
> Point p = proj.forward(lat, lon);
> return
> p.getX() >=0 &&
> p.getX() < proj.getWidth() &&
> p.getY() >= 0 &&
> p.getY() < proj.getHeight();
> }
>
> - Don
>
>
>
> On Mar 2, 2004, at 2:33 PM, Sperlongano Brian M NPRI wrote:
>
>>
>> This is probably a really simple question, but is there a way to
>> determine if a particular Lat/Lon is visible on a MapBean or
>> Projection?
>>
>> Thanks,
>> Brian
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