[OpenLayers-Users] FW: Synchronizing SIMILE Timeline and OpenLayers javascript mapping library

[Andrew Murdoch]

Hello,

I'm trying to get the SIMILE Timeline tool to synchronize events between the timeline bars and an OpenLayers GIS web-map interface.  Has anyone done similar work?  I cross-posted this to the MIT SIMILE general mailing list.

My initial plans to solve this problem include getting data from the Geoserver web-map server (supplying GIS data to OpenLayers) in GeoJSON format.  It seems that Timeline expects a particular format for JSON (or XML) input files however, so I think I need to parse my GeoJSON attribute data and create a Timeline formatted JSON (or XML) file on the fly.  Ideally, Timeline would let you tie certain attribute properties from the GeoJSON file to the needed Timeline properties (start, end, etc.) but I think I'll be able to reformat my data in javascript for the Timeline tool.

My question is how to synchronize the event source loaded into Timeline with the map frame presented by OpenLayers.  Is there a way to extract the events shown in the highlighted slider bar to JSON or XML format on the fly?  Should I wait for a mouse-up event to extract the events shown?  Once I have a JSON file of events (with their latitude and longitude attributes) I think I can load the JSON into OpenLayers as a Vector Layer and refresh the map.  I may need to reformat the Timeline output back to GeoJSON format for import to OpenLayers however.

Does it  sound like I'm on the right track, or am I making this way too complicated?  What methods do I need to call to extract the events shown in the highlighted slider bar and what format would that extract be in?  Are there JSON javascript libraries I should consider using for the format conversions back and forth between Timeline JSON format and GeoJSON format?

Thanks so much for your consideration of this problem.
Andrew Murdoch



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