[OpenLayers-Users] GeoJSON layer on top of google - repeated load of features

[Adorian Ardelean]

OK I found solution: I had to place stylemap as option when defining
specimen vector layer.

Hope all is ok now.

Thank you,
Adorian

http://mybiosis.info

On Wed, Jul 2, 2008 at 8:16 PM, Adorian Ardelean <mynature at gmail.com> wrote:

> Hi,
>
> *Yes* the position of features on map is OK now  (I initially added in the
> same place only this: "projection: new OpenLayers.Projection("EPSG:4326")".
> Thank you!
>
> However, the style map does not function yet.
>
> Works OK under:
> specimens2 = new OpenLayers.Layer.GML("specimens", "geojson.php", {format:
> OpenLayers.Format.GeoJSON, projection: new
> OpenLayers.Projection("EPSG:4326"), styleMap: new
> OpenLayers.StyleMap(style)});
>
> but not as
> var p = new OpenLayers.Format.GeoJSON({externalProjection: new
> OpenLayers.Projection('EPSG:4326'),internalProjection:
> map.getProjectionObject(), styleMap: new OpenLayers.StyleMap(style)});
>
> Tthis is a template context styling depending on value of parameters in
> GeoJSON file.
>
> Any quick hints?
> Adorian
>
>
>
>
> On Wed, Jul 2, 2008 at 3:55 PM, Eric Lemoine <eric.c2c at gmail.com> wrote:
>
>> Hi. How about that:
>>
>> var format = new OpenLayers.Format.GeoJSON({externalProjection: new
>> OpenLayers.Projection('EPSG:4326'),internalProjection:
>> map.getProjectionObject()});
>>
>> Note that i haven't tested this.
>>
>> Eric
>>
>> 2008/7/2, Adorian Ardelean <mynature at gmail.com>:
>> > Hi,
>> >
>> > First of all thank you for the prompt suggestion. Worked perfectly and I
>> was
>> > able to include also a style to work with properties defined within
>> GeoJSON
>> > file:
>> > *
>> > specimens = new OpenLayers.Layer.GML("specimens", "geojson.php",
>> {format:
>> > OpenLayers.Format.GeoJSON, projection: new
>> > OpenLayers.Projection("EPSG:4326"), styleMap: new
>> > OpenLayers.StyleMap(style)});*
>> >
>> > The situation I've encountered now is that data from this layer has to
>> be
>> > regenerated with every zoomend event (I do some clustering on server
>> side to
>> > limit the number of features to less than 100 points - the return could
>> be
>> > easily in hundreds or more). The part with zoomend event I can handle.
>> > However, I do not know what is the best strategy to handle this
>> situation
>> > further:
>> >
>> > 1. delete the whole layer and recreate a new GML layer (using code
>> above)
>> > every time? This produces some problems in handling controls (as I
>> interpret
>> > from reaction of the scripts). The controls dedicated to layer
>> "specimens"
>> > does not function anymore. I have to redeclare it again.
>> >
>> > 2. create a vector layer and load and delete features with zoom events
>> > without removing layer and controls.
>> >
>> > For second solution I have found the piece of code below, (which also
>> works)
>> > but returns me to the initial question how do I specify in this context
>> > projection an style parameters?:
>> >
>> > *OpenLayers.loadURL("geojson.php", {}, null, styleMap: new
>> > OpenLayers.StyleMap(style)}, onLoadgml, onLoadFailedgml);
>> >
>> > function onLoadgml(r) {
>> >      if (r.status == 200) {
>> >         var p = new OpenLayers.Format.GeoJSON();
>> >          var f = p.read(r.responseText);
>> >          specimens.addFeatures(f);
>> >      }
>> > }*
>> > *
>> > ....
>> >
>> > *I would somehow prefer the second strategy. Could somebody give me a
>> hint
>> > on how to include *{format: OpenLayers.Format.GeoJSON, projection: new
>> > OpenLayers.Projection("EPSG:4326")* in script so that OL renders vector
>> > features at the right place*?
>> >
>> > *All the best,
>> > Adorian
>> >
>> > On Sat, Jun 28, 2008 at 5:32 PM, Christopher Schmidt <
>> > crschmidt at metacarta.com> wrote:
>> >
>> >> On Sat, Jun 28, 2008 at 04:39:19PM +0200, Adorian Ardelean wrote:
>> >> > Hi,
>> >> >
>> >> > I am trying to load a GeoJSON file in a layer on top of a google map
>> >> > (OpenLayers 2.6).
>> >> >
>> >> > I used for now:
>> >> > var colfeatures = new OpenLayers.Layer.GML("specimens",
>> "geojson.php",
>> >> > {format: OpenLayers.Format.GeoJSON});
>> >> > map.addLayer(colfeatures);
>> >> >
>> >> > Entities show up on the map somewhere close to 0,0. For other vector
>> >> > entities (coordinates) I push through code this is solved with
>> >> >
>> >> > var g = new OpenLayers.Projection("EPSG:4326");
>> >> > var p = new OpenLayers.Projection("EPSG:900913");
>> >> >
>> >> > and .tranform(g,p)
>> >> >
>> >> > but I do not know how to apply this directly on features read from
>> >> GeoJSON.
>> >> > Is there a way to loop through all entities in colfeatures and apply
>> >> > transform(g.p) or can somebody suggest me a better approach?
>> >> {format: OpenLayers.Format.GeoJSON} ->
>> >>  { format: OpenLayers.Format.GeoJSON,
>> >>   projection: new OpenLayers.Projection("EPSG:4326")
>> >>  }
>> >>
>> >> Regards,
>> >> --
>> >> Christopher Schmidt
>> >> MetaCarta
>> >>
>> >
>> >
>> > http://mybiosis.info
>> >
>>
>
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