[Mapserver-inspire] options/questions regarding multi language support

[Stephan Meißl]

Hi Stefan,

thanks for the great write-up of the possibilities. Could you maybe
start a wiki page and collect the discussion (pro/cons) there? 

As I see it the main question is if we want a quick hack for INSPIRE
(e.g. A1 and B2) or something in the direction of "real" language
support (e.g. AB3).

I'm inclined to opt for a scalable solution like your method 3 or even 5
but understand that for the moment a simpler solution might be
favorable.

Curious about other opinions.

cu
Stephan


On Wed, 2011-05-25 at 20:33 +0200, Stefan Leopold wrote: 
> hello
> 
> in the following I try to summarize the different options available
> when implementing multi language support for the inspire view service,
> hope you can provide me some hints about your preferences, pros/cons,
> foreseeable problems during implementation,... as it definitely
> affects client usage too
> 
> -----------------------------------------------------
> 
> as far as I understand, we have to differentiate between two types of
> "data" for multi language support:
> 
> #A# language specific metadata values
> "wms_title" "my title"
> "wms_title" "mein titel"
> 
> and
> 
> #B# language dependent reference data
> DATA "shapes/rivers_eng.shp" 
> DATA "shapes/rivers_ger.shp" 
> 
> -----------------------------------------------------
> 
> until now I can think of five different methods to handle them (I'm
> sure there are much more):
> 
> (1) key extension
> #A#
> "wms_title_eng" "my title"
> "wms_title_ger" "mein titel" 
> 
> #B#
> not appropriate imo
> 
> the main question here is: should the resolving happen at
> - write time (i.e. only wms_title goes into mapobject)
> or 
> - read time (everything goes into mapobject, corresponding key e.g.
> wms_title_ger is used for reading -> perhaps problematic to validate,
> also need
> to be aware that key has _langaguage extension)
> 
> (2) runtime substitution
> #A#
> not appropriate imo
> 
> #B#
> DATA "shapes/rivers_%language%.shp" 
> 
> with "language" being a request parameter or global setting
> 
> already implemented in mapserver -
> http://mapserver.org/cgi/runsub.html - for several (covering all
> required?) parameters
> 
> (3) externalization
> #A#
> "wms_title" "IDC_TITLE"
> 
> #B#
> DATA "IDC_SHAPES_RIVERS" 
> 
> with external files e.g.
> lang.eng
> IDC_TITLE=my title
> IDC_SHAPES_RIVERS=shapes/rivers_eng.shp (or
> IDC_SHAPES_RIVERS=shapes/eng/rivers.shp)
> 
> lang.ger
> IDC_TITLE=mein titel
> IDC_SHAPES_RIVERS=shapes/rivers_ger.shp (or
> IDC_SHAPES_RIVERS=shapes/ger/rivers.shp)
> 
> i think it's the most common way for internationalization and there
> are many tools available to externalize strings
> 
> again the question is: at which time the externalized value should be
> resolved (e.g. while parsing mapfile, during
> msApplySubstitutions, ...)
> 
> (4) merge (i.e. using INCLUDE)
> #A#
> not appropriate imo
> 
> #B#
> standard.map
> LAYER
> ...
>  NAME "rivers"
>  INCLUDE "rivers.map"
> ...
> 
> rivers.map
> DATA "shapes/rivers_ger.shp" 
> 
> already implemented in mapserver -
> http://mapserver.org/mapfile/Include.html - based on languange the
> corresponding map file (e.g. 
> shapes/ger/rivers.shp) is included
> 
> (5) override (i.e. override certain values of the original "unchanged"
> mapfile)
> 
> - with comments (probably generated by tool)
> #A# and #B#
> standard.map
> "wms_title" "my title" #1
> ...
> LAYER
> ...
>  NAME "rivers"
>  DATA "shapes/rivers_eng.shp" #2
>   ...
> 
> override.ger
> 1="mein titel
> 2="shapes/rivers_ger.shp"
> 
> - explicitly referencing key
> #A# and #B#
> standard.map
> "wms_title" "my title"
> ...
> LAYER
> ...
>  NAME "rivers"
>  DATA "shapes/rivers_eng.shp"
>  ...
> 
> override.ger
> "wms_title"="mein titel
> "layer[rivers]/DATA"="shapes/rivers_eng.shp" or "layer[0]/DATA"
> "shapes/rivers_ger.shp" or ....
> 
> problem is how to provide path in hierarchical structures like layers
> (perhaps XPath syntax?)
> 
> -----------------------------------------------------
> 
> patch #3608 - http://trac.osgeo.org/mapserver/ticket/3608 - currently
> uses #A#(1) applied at read time and #B#(2)
> 
> -----------------------------------------------------
> 
> 
> hope it is not too confusing, looking forward to your feedback
> br
> stefan
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