[mapserver-users] zoomable slider (looking) map from Mapserver

[Brent Fraser]

Bob,

   I'm not sure I've successfully visualized your solution, but I do 
appreciate your problem.  While the web mapping community has come up 
with decent set of concepts and tools for spatially navigating data 
(pan, zoom, etc), we seem to be lacking a standard, intuitive (?) set of 
tools for temporally exploring data with a strong geospatial connection.

   Some of the temporal concepts stolen from geography that we'll have 
to deal with: event extents, event resolution/density, temporal scale 
(especially with respect to animation),...

   I think the eventual solution will be JavaScript-based, maybe nearly 
the size of OpenLayers effort.  I'm leaning towards having separate 
panel (like we tend to have for the legend, etc) for time navigation.  
For layout and interaction ideas, have a look at the D3 examples 
(https://github.com/mbostock/d3/wiki/Gallery), particularly the 
CrossFilter (http://square.github.com/crossfilter/) example.

   Sorry, no solution; just encouragement...

Best Regards,
Brent Fraser

On 4/9/2013 7:48 AM, Basques, Bob (CI-StPaul) wrote:
>
> All,
>
> Ok, granted weird title for a posting.
>
> I have a little reporting project that I'm thinking about related to 
> GPS tracking.  Bouncing the idea off of folks here in the hopes that 
> someone may have tried this somewhere else or maybe has a better way.
>
> I need to generate a slider control for handling sorting through the 
> GPS data for individual vehicles on a daily basis.  The idea is to 
> build a rapid, visually oriented, lookup system for the data.  To 
> begin with, I would like to start the process by querying for the data 
> for a single GPS ID for a 24 hour period, generate a time based slider 
> control that can be used to pick a point in time, and then have a 
> slippy map (OpenLayers) auto zoom to that location, once a location 
> has been decided on.
>
> I found an example on the Openlayers site for the slippy map part, I 
> have a service (yet to build) that can grab the location data by time 
> increments of 24 hours, but the slider part is looking like it might 
> be a bit intensive if built in a standard way.  The data for the GPS 
> devices can come in all sorts of time resolutions, some are based on 
> 15 -- 20 sec updating, while others are using 3 sec update 
> increments.  The resulting 24hr dataset can be somewhat sizeable as a 
> result.
>
> Here is my weird idea.  Make the Slider into a  MapServer map call 
> that is aggregated at certain time increments (Map tile pyramid 
> levels, only in a single direction, left/right)  if the  slider is 
> zoomed more resolution of time appears for picking the location in the 
> slippy map.  The slider becomes a real wide but not very tall map but 
> only for displaying, and picking by the user a new time increment.  
> This approach should therefore compensate for browser view size as 
> well as density of time data, by making an appropriately sized, scaled 
> tile on demand.  It should also be adaptable in the future to starting 
> out with larger time increments to show where GPS activity was, and 
> then to zoom in on that time increment for detailed analysis.
>
> Ok, I'm ready, tell me it's a stupid way to go . . .
>
> Bobb
>
>
>
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