You can speeden up the process a lot if you need to do large comparisions. I
keep an array of bounds and only do Contains on polygons from which the
bounds are inside. You can also just put that in the method itself
v2 syntax:
/**
* @desc Check if polygon contains point.
* @return boolean
**/
GPolygon.prototype.Contains = function(point) {
if(!this.getBounds().contains(point)){
return false;
}
var j=0;
var oddNodes = false;
var x = point.lng();
var y = point.lat();
for (var i=0; i < this.getVertexCount(); i++) {
j++;
if (j == this.getVertexCount()) {j = 0;}
if (((this.getVertex(i).lat() < y) && (this.getVertex(j).lat() >= y))
|| ((this.getVertex(j).lat() < y) && (this.getVertex(i).lat() >= y)))
{
if ( this.getVertex(i).lng() + (y - this.getVertex(i).lat())
/ (this.getVertex(j).lat()-this.
getVertex(i).lat())
* (this.getVertex(j).lng() - this.getVertex(i).lng())<x ) {
oddNodes = !oddNodes;
}
}
}
return oddNodes;
};
Comparing to bounds is a maximum of eh, maybe 4 operations so a LOT faster,
this would make it a lot faster.
2010/4/23 Martin Revert <[email protected]>
> There's an issue reported about this, but it is in Need More Info
> status since february 2010.
> It would be nice to have a Polygon.isLatLngInside
> Circle.isLatLngInside and Rectangle.isLatLngInside methods in the API
> from scratch.
>
> For circles I guess that is more easy and less CPU consuming to
> estimate the difference between the total distance of the center and
> the point (using Havershine's formula) and the total radius. For
> irregular polygons, I think Björn's suggestion is the way to go but if
> need use that for many polygons yo could expect severe time delays
> when that prototype is invoked.
>
>
> On 21 abr, 11:23, Björn Brala <[email protected]> wrote:
> > The group will prabably make the code unreadable. Here's a link:
> >
> > http://www.geostart.nl/GPolygon.contains.js
> >
> > 2010/4/21 Björn Brala <[email protected]>
> >
> >
> >
> > > You should sjust the Contains function to v3.
> >
> > > The things you need to change is getVertextCount() to (getPath().length
> im
> > > guessing)
> >
> > > And perhaps some of the other methods, but the base should be the same.
> >
> > > /**
> > > * @desc Check if polygon contains point.
> > > * @return boolean
> > > **/
> > > GPolygon.prototype.Contains = function(point) {
> > > var j=0;
> > > var oddNodes = false;
> > > var x = point.lng();
> > > var y = point.lat();
> > > for (var i=0; i < this.getVertexCount(); i++) {
> > > j++;
> > > if (j == this.getVertexCount()) {j = 0;}
> > > if (((this.getVertex(i).lat() < y) && (this.getVertex(j).lat() >=
> y))
> > > || ((this.getVertex(j).lat() < y) && (this.getVertex(i).lat() >=
> y)))
> > > {
> > > if ( this.getVertex(i).lng() + (y - this.getVertex(i).lat())
> > > / (this.getVertex(j).lat()-this.getVertex(i).lat())
> > > * (this.getVertex(j).lng() - this.getVertex(i).lng())<x ) {
> > > oddNodes = !oddNodes;
> > > }
> > > }
> > > }
> > > return oddNodes;
> > > };
> >
> > > 2010/4/21 Charles <[email protected]>
> >
> > > Hi, I want to know if it's possible in v3 to know if a polygon
> > >> contains a certain coordinate.
> >
> > >> I have polygons representing the districts of a city and users enter
> > >> their address (which I reverse geocode to get the latlng of where they
> > >> live) to know in which district they are. I have no problem with
> > >> drawing polygons or getting the coordinates, the only thing missing is
> > >> getting to know of the coordinate is in a certain polygon.
> >
> > >> I know that in v2 there was a GPolygon.contains method but it seems it
> > >> is not in v3. I've searched a lot today and all I found were tutorials
> > >> for binding clicks... this is not what I want.
> >
> > >> Thanks
> >
> > >> --
> > >> You received this message because you are subscribed to the Google
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> > >> "Google Maps JavaScript API v3" group.
> > >> To post to this group, send email to
> > >> [email protected].
> > >> To unsubscribe from this group, send email to
> > >> [email protected]<google-maps-js-api-v3%[email protected]>
> <google-maps-js-api-v3%[email protected]<google-maps-js-api-v3%[email protected]>
> >
> > >> .
> > >> For more options, visit this group at
> > >>http://groups.google.com/group/google-maps-js-api-v3?hl=en.
> >
> > > --
> > > Bjorn Brala
> > > ----------------
> > >www.GeoStart.nl/english/- Google maps - Swis Webdesign
> > >www.twitter.com/bbrala
> >
> > --
> > Bjorn Brala
> > ----------------www.GeoStart.nl/english/- Google maps - Swis
> Webdesignwww.twitter.com/bbrala
> >
> > --
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> > To post to this group, send email to
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> > To unsubscribe from this group, send email to
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> .
> > For more options, visit this group athttp://
> groups.google.com/group/google-maps-js-api-v3?hl=en.
>
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>
--
Bjorn Brala
----------------
www.GeoStart.nl/english/ - Google maps - Swis Webdesign
www.twitter.com/bbrala
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