[mapguide-users] Reading data in real time?

[Andrew DeMerchant]

Yep, it would be fixed geographic points with changing attributes 
(likely color-coded based on 3 different ranges of numbers). I sort of 
figured that MG wouldn't know enough to poll on it's own, but thought 
that maybe there was some way of telling it...that maybe it had a 
mechanism to do it, but that it needed some information somewhere to 
actually DO it.

Andrew


Dave Wilson wrote:
> You would have to write a routine to refresh on your own. Otherwise 
> MapGuide would have to have a mechanism to poll the data and see 
> changes. This isn't an easy task. Unless transaction log information 
> or some equivalent is exposed there is no way for MapGuide to know 
> specifically what data changed and whether a refresh makes sense.
>  
> What if a website used 5 maps pointing to 30 or so layers coming from 
> a database. How would it know which ones to poll for changes? If the 
> data was updating every second it would take probably a second or 2 to 
> poll the database and find out a change has occurred in order to start 
> a refresh.
>  
> What kind of data are you trying to track that changes every second? 
> I'm guessing it's not positioning, but some attribute changing?
>  
> Dave
> ------------------------------------------------------------------------
> *From:* mapguide-users-bounces at lists.osgeo.org 
> [mailto:mapguide-users-bounces at lists.osgeo.org] *On Behalf Of *Andrew 
> DeMerchant
> *Sent:* Wednesday, February 14, 2007 6:14 AM
> *To:* MapGuide Users Mail List
> *Subject:* [mapguide-users] Reading data in real time?
>
> If I had a database that was constantly being updated (say every 1 
> second) with data, and I had made a themed layer for that data, would 
> MapGuide handle the refreshing of the layers on it's own? Would it see 
> that the data has changed, and then force that layer to refresh from 
> the database, or would I have to write something to refresh every few 
> seconds? We're not really talking about a lot of data here, really - 
> just maybe 100 geographic points, with 1 number each point (which 
> would be themed based on the range that that number falls in)......
>
> Andrew
>
> -- 
> 	*Andrew DeMerchant*
> *Computer Technologist*
> ph.1-877-2GEMTEC x.163
> fax 506-453-9470
>
> /GEMTEC Limited <http://www.gemtec.ca>
> /191 Doak Road
> Fredericton, NB, Canada
> E3C 2E6
>
> ------------------------------------------------------------------------
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-- 
	*Andrew DeMerchant*
*Computer Technologist*
ph.1-877-2GEMTEC x.163
fax 506-453-9470

/GEMTEC Limited <http://www.gemtec.ca>
/191 Doak Road
Fredericton, NB, Canada
E3C 2E6

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