MapServer Application Design Questions

[Tamas Szekeres]

Folks,

According to the design principles I've issued and RFC that could
provide support for using one layer as the data source of another and
provide built-in operations on the shapes that is extensible for the
many of typical scenarios have been implemented by mapscript before.

In my opinion currently many of the mapscript applications implement
such common things like query a layer based on a shape or attributes,
create operations on the results, display the results in a separate
layer, issue a subsequent query based on the results of another query
that should instead be supported internally by mapserver. You could
simply create a mapfile and declare how the layers are connected to
each other and what transformations should be used in the processing
chain.

I don't think this kind of functionality would eliminate the need for
using scripting at the server side, but in some of the scenarios
(mostly for the stateless ones) it would be quite helpful and
supported for the CGI style applications as well.

I admit that this addition would anyway provide new direction to the
project and we should indeed consider how it violates the original
statement describing mapserver as:
"MapServer is not a full-featured GIS system, nor does it aspire to be"


Here's the link to the corresponding RFC for reference:
http://mapserver.gis.umn.edu/development/rfc/ms-rfc-22a

Best regards,

Tamas



2008/1/23, Ed McNierney <ed at topozone.com>:
>
>
>
>
> Adrian –
>
>
>
> If you are running a .NET/C# application, that application can – using
> ServerXMLHttpRequest calls – make as many requests to a MapServer CGI as you
> need to produce a single output page.
>
>
>
> I am not suggesting that that's the best design for your application.  But
> you started with a very specific question about thread safety and we're
> trying to back up to the broader question of application design (hence the
> edit I made to the Subject line), because it seems like that's what you are
> trying to accomplish.  If you'd like assistance with that, then you'll need
> to really describe your application in detail.  Your last email with lists
> of layers, etc. was a good description of your data (although you didn't
> talk about updates and/or update rates).  But you didn't, for example,
> describe the situation below.
>
>
>
> There are many users here with expertise in many different sorts of
> MapServer applications.  But we can't help if we only have little bits of
> information, and if you only send detailed, specific requests for "how to do
> it".  If you can take the time to really describe your application then you
> will both be in the best position to get advice from users on this list and
> we will be able to best use our time by providing information that's really
> useful!
>
>
>
> -          Ed
>
>
>
> P.S. It also really helps to include the previous message history in your
> replies, so we can all understand the context, and so users who might now be
> reading this message (because they didn't know much about thread safety but
> know a lot about application design) will know what's going on – thanks.
>
>
>
> Ed McNierney
>
> Chief Mapmaker
>
> Demand Media / TopoZone.com
>
> 73 Princeton Street, Suite 305
>
> North Chelmsford, MA  01863
>
> Phone: 978-251-4242, Fax: 978-251-1396
>
> ed at topozone.com
>
>
>
>
> From: UMN MapServer Developers List [mailto:MAPSERVER-DEV at LISTS.UMN.EDU] On
> Behalf Of adrian kruk
>  Sent: Wednesday, January 23, 2008 3:07 AM
>  To: MAPSERVER-DEV at LISTS.UMN.EDU
>  Subject: Re: [UMN_MAPSERVER-DEV] Is MapServer Thread-safe?
>
>
>
>
>
>
>
> My first reaction is to wonder why you feel you need MapScript (which leads
> to the whole issue of thread safety in the first place).  I would be
> inclined to build your application as I have done others, using the .NET/C#
> environment to process Web requests and then compute an appropriate WMS
> request to render the map image required.  You would use MapServer in simple
> CGI/WMS mode, sending HTTP requests for images which you then retrieve in
> your C# code and embed in an output page of your design.
>
>
>
>  Ok I will give an example of functionality. MapScript has map object, shape
> object, layer object, etc. With using these, it is simple to run query in
> one layer, get results as shapes and then run query on different layer,
> create new layer, then get image, i can store map object in application
> cache in very simple way, etc, etc.
>  It is possible in CGI/WMS? If it is tell me how to do it.
>
>
>
>
>
>