[OpenLayers-Users] Interactive hot spots on a map for large, complex vector geometries

[Martin Davis]

Another technique designed to meet this requirement is UTFGrid:

https://www.mapbox.com/foundations/an-open-platform/#utfgrid

OpenLayers apparently has support for UTFGrids:

Doc:
http://dev.openlayers.org/apidocs/files/OpenLayers/Control/UTFGrid-js.html
Example:  http://openlayers.org/dev/examples/utfgrid.html

The tricky part is generating the UFTGrid!  Not sure what tools there are
out there for doing this.  It would be nice if there was a map server which
could generate these on-the-fly...



On Wed, Jun 25, 2014 at 3:35 AM, Rob Marjot <rob.marjot at gmail.com> wrote:

> Dear list,
>
> I'm in the quest of developing a performant webmapping application
> involving large, complex vector objects (pipelines) originating from CAD.
> In the application, these objects need to be interactive.
>
> Whether complex or not: the vectors will only be (possibly partly: clipped
> by the map extents) rendered to a limited number of pixels. In OpenLayers
> 3, this idea is exploited: before rendering vectors are pre-processed by
> quantizing (and removing duplicate / co-linear) coordinates. (The
> algorithm has been implemented by Tim Schaub
> <http://tschaub.net/blog/2014/03/04/topology-preserving-simplification.html>
> ).
>
> Applying quantization (and clipping) dramatically reduces the serialized
> (GeoJSON) size of the geometries. Yet, since my coordsys is in meters,
> exchanging pixel coordinates will reduce the size even further...
>
> My question: is there a layer type that takes pixel coordinates, relative
> to a map corner? Effectively, this would allow me to create hotspots on a
> map that was rendered purely serverside.
>
> I fully understand (and tend to accept) the downside of required traffic
> upon each panning / zooming. It will be acceptable to request a refresh of
> hotspots with a delay of a 1 sec or so.
>
> Otherwise, I'm open to any suggestion taking another approach :))
>
> Thank you in advance!
>
> Rob
>
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