[mapserver-dev] Proposal to add built-in OpenLayers map viewer

[Daniel Morissette]

The need I'm trying to address is the ability for mapfile developers to
quickly test a mapfile just by typing a simple URL in their web browser.
While I can appreciate that admin tools and generic templates for all
sorts of viewers and frameworks would be nice to have, that is out of
scope for what I am currently proposing.

What I propose is to add a simple function to mapserv.c (just a few
lines, really) that will spit out a few lines of HTML/JavaScript to
instantiate a very simple OpenLayers based viewer for a given mapfile
in response to a mapserv CGI request with mode=openlayers or a WMS
GetMap request with format=application/openlayers. I do not envision the
use of external or configurable templates for this since that would
imply dependencies on external files an I would ideally like something
really simple aimed at mapfile developers that works out of the box with
just the standalone mapserv executable and a regular mapfile without any
special configuration.

Does my explanation make sense? Is this not considered useful enough by
itself to justify adding to the mapserv CGI? If there are no objections
to this little addition then I will write a RFC for it.

Daniel


Lime, Steve D (DNR) wrote:
> So where are we at? I do like the idea. The technical solution, IMHO,
> will probably point to how this might work operationally. For example,
> if the plan were to simply embed a HTML/OL template in code then a
> mode=openlayers would make sense. However, if the template were stored
> externally and a basic one shipped with MapServer then I’d opt for
> mode=browse&template=openlayers. The advantage of the external templates
> is extensibility and users could edit the one(s) provided or add their
> own. They could also disable the functionality altogether by removing
> all templates. The downside is setting up access and then security. If
> external templates used the templating code and magic strings that would
> mitigate many issues…
> 
>  
> 
> Steve
> 
>  
> 
> *From:* mapserver-dev-bounces at lists.osgeo.org
> [mailto:mapserver-dev-bounces at lists.osgeo.org] *On Behalf Of *Tamas Szekeres
> *Sent:* Friday, September 24, 2010 4:46 PM
> *To:* Daniel Morissette
> *Cc:* MapServer Dev List
> *Subject:* Re: [mapserver-dev] Proposal to add built-in OpenLayers map
> viewer
> 
>  
> 
> Daniel,
> 
> Adding a viewer with zoom and pan capabilities is a good idea which is
> better then having a single image in some cases. I foresee a reasonable
> Web administration interface to mapserver could also be established by
> such additions which would be a requirement too.
> However embedding code from a separate project seems to be a hassle,
> though the technical solution hasn't yet been mentioned in the ticket.
> 
> I would be in favour of doing either:
> 
> 1. Create a simple  (mapserver specific) .js to provide the required
> functionality (which could be extended later with further options)
> 2. Provide a (pluggable) interface for use by the potential viewers in
> mapserver, and  create a separate support package for at least one (like
> openlayers for instance) and include the external code to this package.
> 
> 
> (Just to put my 2 cents in)
> 
> Best regards,
> 
> Tamas
> 
> 
> 
> 
> 2010/9/24 Daniel Morissette <dmorissette at mapgears.com
> <mailto:dmorissette at mapgears.com>>
> 
> This was discussed at the code sprint in Barcelona, and I just created a
> ticket for it. We'd like to add this to 6.0... but I am realizing just
> now that maybe I should start with a RFC...
> 
> Anyway, here is what I wrote in the ticket, please feel free to comment,
> keeping in mind this has to remain __simple__:
> 
> http://trac.osgeo.org/mapserver/ticket/3549
> 
> Every once in a while we get requests for a simple way to test a
> mapfile. One way to handle this could be to do as GeoServer does and
> provide a built-in OpenLayers based map viewer. In the GeoServer case,
> this viewer is returned when one issues a WMS GetMap request with
> format=application/openlayers in it.
> 
> I propose that we provide a similar functionality in MapServer, which
> would be triggered in one of two ways:
> 
> 1- Using mapserv?map=/path/to/my.map&'''mode=openlayers''' ... in this
> case the viewer would be initialized based on the mapfile defaults, and
> some of the traditional mapserv CGI params may also work (such as map
> size, layer selection, etc.)
> 
> 2- Using '''format=application/openlayers''' in a WMS GetMap request as
> GeoServer does. Note that in this case the rest of the GetMap parameters
> would be used to configure the map to view (BBOX, WIDTH, HEIGHT, LAYERS,
> etc.)
> 
> Both cases would call the same function internally to produce a simple
> OpenLayeres viewer with one singletile layer for the whole map with the
> selected layers.
> 
> 
> --
> Daniel Morissette
> http://www.mapgears.com/
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> 
>  
> 
> 
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-- 
Daniel Morissette
http://www.mapgears.com/