[OpenLayers-Users] Vector-like feature interaction with large, complex layers

[Roald de Wit]

Hi Tom,

When your geometries are too many or too complex (or both) you need to 
compromise somewhere.
There are 2 more approaches you can take:

1) Use an approach similar to what Eric mentioned. Use a WMS layer, but 
on hover send a request to the server to get the id (and possible other 
attributes) of the feature 'under' the click and then another WMS 
request using that id to only draw that feature with a different style 
(to mimic highlighting) and draw that over the other WMS layer. This is 
not as responsive as 'real' features but works.

2) You can put FeatureServer [1] in between your client and your service 
and tell FS to simplify the geometries based on your zoomlevel (or 
resolution to be precise). FS can do some processing like simplify, 
buffer, etc. This approach works quite well, but *only* for simplifying 
the geometries (reducing the amount of vertices), not for reducing the 
amount of geometries. If you have too many geometries to show, you'd 
still need to revert to WMS

Does this help?

Regards, Roald

Tom B wrote:
> Thanks, Ian; hm, many of the polygons we're using are adjoining, like
> counties, and my guess is that generalizing them would make their borders a
> bit messy, and it might be a bit of work to try it out.  I'll ask our
> GeoServer/OL support person what he thinks about it, though.
>
> Any other ideas for this, by any chance?
>
> -Tom
>
>
>
> Ian Turton wrote:
>   
>> Could you generalize your polygons to speed up vector performance?
>>
>> Ian
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