Re: [OpenMap Users] My comments on OpenMap used as an Applet

From: OpenMap Support <>
Date: Sat, 18 Jun 2005 11:47:28 -0500

Hi Mariusz,

On Jun 17, 2005, at 3:19 AM, Mariusz Chmielewski wrote:

> Recently i had to using the OpenMap implement an applet viewing the
> CADRG data i tried serveral different solutions to achieve that and
> here are some conclutions:
> - including the CADRG data inside the JAR of an applet itself is
> not a grat idea, but i tried it and it is not working the framework
> shows errors taht the A.toc file is wrong i guess that Open Map is
> not able to load CADRG (RPF layer) from inside the JAR

No, the RpfLayer can read data from within a jar. Sounds like a
configuration problem.

> - why do not allow the OpenMap Applet to load data from local
> resources after signing it by the trustred certificate is it so
> hard to implement??

Hopefully someone with experience with signed applets would be able
to answer this for you.

> - what should be done to implement such functionality (on server
> side i implement a service which loads CADRG - and sends only
> scraps of needed data to applet on the client side ) can CADRG data
> be sent over HTTP??

Sure, you can specify the RPF directory as a URL and the frames will
be passed that way.

> - i read the documentation about the linked layer but i do not
> understand how to provide the data for the linked layer i use JBoss
> Application server (shoud i provide a servlet taht sends the byte
> data for the map) or FTP service on the server??

You would need to implement a LinkServer that provided the OMRasters
for CADRG data, but that would be slow, since the LinkLayer doesn't
know how to cache things from the server, and you'd be constantly
refreshing images with pans and zooms.

There is a CORBA solution for an RPF server in the src/corba tree
that includes the client layer and server, but that really requires
you to be familiar with CORBA configurations.

> Is using applet a wrong idea for my application (shoud i use Web
> Service Instead )??

You could do that as well, but it depends on the connection speed of
the client and the size of the image you are sending (could be
slow). You would configure an ImageServer with a CADRG layer (to
start using a SimpleHttpImageServer), and use a SHISPlugIn to display
images from that image server. If the performance was acceptable,
then you would use the servlet to handle the connection requests for
the ImageServer instead of the SimpleHttpImageServer, which can't
handle heavy client loads.


- Don

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Received on Sat Jun 18 2005 - 12:52:55 EDT

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