Hello Armin,
thank you for your detailed description.
[should go to the Wiki to some extend]
On Thu, 08 Jun 2006 19:45:28 +0200 Armin Burger <armin.burger at gmx.net>
wrote:
> Stephan,
>
> at the moment I have not access to the code because it's used only
> for an application at work. But I will describe the steps to keep in
> mind for pmapper and dynamic layers.
>
> There are 2 parts to consider:
>
> 1) The dynamic layers have to be initilized, ie. defined with all
> their properties. This has just to be done once when you want to add
> one or more layers. And it has of course to be repeated if you want
> to add other ones.
>
> 2) Once the layers have been initialized and are referenced for
> p.mapper, you have to add them to the map all the time you want to do
> something with them, ie. for every new map image creation or for
> queries.
>
>
> to 1)
> ---------------
> The script I attached has a function called
> 'dyn_initPMLayerGroups()'. This function has to be completely adapted
> to your application. Dynamic layers can have nearly indefinite
> compositions that I don't see a generic way of doing this. Typically
> one starts with a database query or user input that provides the
> necessary parameters.
OK, done.
Works as expected.
>
> For easier definition I typically use an existing layer as template,
> so I do not have to define all the properties by hand, just the ones
> that differ from dynamic layer to another (think about a layer with
> 10 classes and all the colors etc., would be quite tedious to code
> this all via Mapscript). One can of course also create dynamic layers
> based on different templates at the same time.
>
> The pre-defined layer definitions are saved in the
> $_SESSION['dynLayerList'] as well as the names of them in
> $_SESSION['allGroups'].
>
> The call at the end of this function
> $this->dyn_addLayersToMap($dynLayerList);
>
> adds the layers to the map. When referencing a layer list as argument
> these list is taken, otherwise the same function with argument
> 'false' is used in step 2) (see below).
>
> For each layer definition in this 'dynLayerList' a call is made to
> 'dyn_createMSlayer()' to actually create each single layer and add it
> to the map. You can see that this function uses the template layer
> specified in 'dyn_initPMLayerGroups()'.
>
> At the end of the 'dyn_initPMLayerGroups()' the initialization of
> groups ('new Init_groups') is called again in order to reference all
> these dynamic layers in the session var 'grouplist' for further use
> in p.mapper.
>
> In order to have a way to distinguish between static layers and
> dynamic layers the static ones are also additionally once referenced
> in 'allGroups0' in initmap.php like
> $_SESSION["allGroups0"] = $allGroups;
>
> The layers for templates should have set the status to 'OFF' and
> should not be referenced in allGroups in config.ini if they are only
> templates for dynamic layers. One could probably also define a second
> map file just for the dynamic layers, but I don't know if one can
> transfer the layer definition from one map to another.
OK, now I have some problems. My template does not get recognized by
pmapper. It is simple and called 'template'.
The getLayerByName() inside dyn_createMSlayer() fails. but I cannot say
why.
basically I need to do:
$templateLayer = $this->map->getLayerByName($templateLayName);
$newMSLayer = $templateLayer;
$newMSLayer->setMetaData("DESCRIPTION", $dyn_descr);
$newMSLayer->set("name", $dyn_name);
$newMSLayer->set("status", "ON");
$newMSLayer->set("data", $dyn_data);
This does not work with my template layer, but with others already in
the mapfile?!
What is wrong here?
>
>
> to 2)
> ---------------
> once dynamic layers are initialized they have to be added to the map
> every time the map image is created or the map is queried. In map.php
> there is already the function 'pmap_addCustomLayers()' where one
> needs to add
>
> $dyn = new DynLayer($this->map);
> $res = $dyn->dyn_addLayersToMap(false);
OK, done.
I inserted this:
include_once("dynlayer.php");
if (isset($_SESSION['dynLayerList'])) {
$dyn = new DynLayer($this->map);
$res = $dyn->dyn_addLayersToMap(false);
}
> You will have to do the same for the queries. So add this call also
> in query.php in function 'Query($map)', I hope this is sufficient,
> otherwise you have to investigate further. Printing should already be
> covered by map.php because the printing uses the 'PMap' class.
THis is the next step as soon as I have the getLayerByName-stuff sorted
out...
>
> The dynamic layers are added at the end of the map, so they are drawn
> on top of the existing static layers. I used also always the call
> 'dyn_moveStaticLayersDown()' in order to change the layer orders and
> to move the static layers down in the map file structure, that means
> they are displayed *on top* of the dynamic layers.
>
>
> A slightly different approach instead of 2) would be to initialize
> the layers like in 1), but then write everything to a temp map file
> (using eg. the session var as file name) and then reference this file
> as the map file in the session. This way you could more or less
> completely drop setp 2) because the used map file has always the
> dynamically created layers in it. I normally try to avoid working too
> much with temp files if it does not have real benefits. But you could
> think about that too.
>
> I hope this helps a bit. If you succeed you could also write a
> description for this in the FAQ on the Wiki...
Yes, this are very good hints and should go to the wiki, when I am done
with it.
Again, thanks for your help.
Best regards
Stephan
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