<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#ffffff">
I might start by thinking of this as a visual chatroom or
multiplayer game. From what I've read and experimented a little
with, an AJAX solution where you poll the central server for
position updates (and send your own) or a Comet solution (Like AJAX,
but it's more push-flavored) or, looking to the future, a WebSockets
solution would serve you.<br>
<br>
The advice I got from this board (and even in this thread), which I
think to be sound, is to start with AIAX. Poll the server as often
as you want to check for updates. Later in development, consider
upgrading to one of the above-mentioned.<br>
<br>
I suspect that your timestamp's required accuracy will depend on
your needs. If you do not need absolute precision of time, it might
be good enough to update positions "as received" with no regard for
absolute time. Next most "accurate" would be to use a variable in
the client-side javascript to keep track of a timestamp gotten from
the server with an offset from the time received. From there, your
solutions become more involved. I am working on an application
where absolute time is critical, and a little custom hardware at
each client is required, for example.<br>
<br>
<br>
The others are right, though. JSON, xml, .csv, these are all just
data transport formats. Use what works best for you. You may want
to experiment, as these all involve tradeoffs.<br>
<br>
Michael<br>
<br>
<br>
<br>
On 6/6/2011 5:35 AM, Nicholas Efremov-Kendall wrote:
<blockquote
cite="mid:BANLkTin1pMywA3VvRPFYkBRnx08ycs14vQ@mail.gmail.com"
type="cite">Yeah, you're going to need to get it to work in atomic
time was well to simultaneously update the positions your
describing. So, this is probably going to recall some sort of ajax
function tied to each client spitting the position data into a
server-side script and spitting the updated position data back
into the map. My guess is some sort of event listener on the
feature the user is positioning, and then on the back-end a
multi-user transactional database which stores and updates all the
positions on the map...
<div>
<br>
</div>
<div>So client-side you need your user interaction with the
feature, you should look into the various controls OL has which
let you interact with features in the map, and will probably get
some of the functionality you want. The ajax function here will
have to update the server with the user's position in order to
be able to give that data to other users. </div>
<div><br>
</div>
<div>I have no idea how you'd implement this on the server, but
you're going to have to have each user be able to modify some
sort of spatial database with each user logged into your
application. So that's another piece you'll need, some sort of
server-side login mechanism, which gives users access to modify
the table/dataset of users and positions. </div>
<div><br>
</div>
<div>Updating that database is going have to happen pretty often,
so you'll need something transactional and probably some sort of
complicated SQL...good luck!<br>
<br>
<div class="gmail_quote">On Mon, Jun 6, 2011 at 4:50 AM, Rossko
<span dir="ltr"><<a moz-do-not-send="true"
href="mailto:rossko@culzean.clara.co.uk">rossko@culzean.clara.co.uk</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
<div class="im">> I need a saveStrategy and a way to save
that changes (position, attributes<br>
of the point) at a central point.<br>
<br>
</div>
That's outside the scope of OpenLayers ; you are going to
need some kind of<br>
multiuser database. Choice of what to use may be forced upon
you, by what<br>
kind of server-side resources are available to you or what
environment you<br>
are used to working in.<br>
<div class="im"><br>
> I read something about geojson. Could this match to
my problem?<br>
<br>
</div>
It's just a data transport mechanism, it won't do any saving
or updating for<br>
you, although it could be part of your solution.<br>
<font color="#888888"><br>
--<br>
View this message in context: <a moz-do-not-send="true"
href="http://osgeo-org.1803224.n2.nabble.com/Save-Data-Multiple-User-access-at-same-Time-tp6442182p6444473.html"
target="_blank">http://osgeo-org.1803224.n2.nabble.com/Save-Data-Multiple-User-access-at-same-Time-tp6442182p6444473.html</a><br>
</font>
<div>
<div class="h5">Sent from the OpenLayers Users mailing
list archive at Nabble.com.<br>
_______________________________________________<br>
Users mailing list<br>
<a moz-do-not-send="true"
href="mailto:Users@lists.osgeo.org">Users@lists.osgeo.org</a><br>
<a moz-do-not-send="true"
href="http://lists.osgeo.org/mailman/listinfo/openlayers-users"
target="_blank">http://lists.osgeo.org/mailman/listinfo/openlayers-users</a><br>
</div>
</div>
</blockquote>
</div>
<br>
</div>
<pre wrap="">
<fieldset class="mimeAttachmentHeader"></fieldset>
_______________________________________________
Users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Users@lists.osgeo.org">Users@lists.osgeo.org</a>
<a class="moz-txt-link-freetext" href="http://lists.osgeo.org/mailman/listinfo/openlayers-users">http://lists.osgeo.org/mailman/listinfo/openlayers-users</a>
</pre>
</blockquote>
</body>
</html>