.. _labelencoding:

*****************************************************************************
 Display of International Characters in MapServer
*****************************************************************************

:Author: Jeff McKenna
:Contact: jmckenna at gatewaygeomatics.com
:Last Updated: 2010-08-10

.. contents:: Table of Contents
    :depth: 3
    :backlinks: top

Credit
======

The following functionality was added to MapServer 4.4.0 as a part of a project sponsored by the 
Information-technology Promotion Agency (IPA), in Japan.  Project members included: Venkatesh Raghavan, 
Masumoto Shinji, Nonogaki Susumu, Nemoto Tatsuya, Hirai Naoki (Osaka City University, Japan),
Mario Basa, Hagiwara Akira, Niwa Makoto, Mori Toru (Orkney Inc., Japan), and Hattori Norihiro 
(E-Solution Service, Inc., Japan).

Related Links
=============

- MapServer `ticket:858 <http://trac.osgeo.org/mapserver/ticket/858/>`__ 

Requirements
============

- MapServer >= 4.4.0
- MapServer compiled with the libiconv library

How to Enable in Your Mapfile
=============================

The mapfile :ref:`LABEL <label>` object's parameter named *ENCODING* can be used to convert strings from its original 
encoding system into one that can be understood by the True Type Fonts.
The *ENCODING* parameter accepts the encoding name as its parameter.

This uses GNU's libiconv ( http://www.gnu.org/software/libiconv/ ) so theoretically, every string 
with an encoding system supported by libiconv can be displayed as labels in MapServer as long as 
it has a matching font-set.

Step 1: Verify ICONV Support and MapServer Version
--------------------------------------------------

Execute ''mapserv -v' at the commandline, and verify that your MapServer version >= 4.4.0 and it includes ''SUPPORTS=ICONV'', such as:

::

   > mapserv -v

     MapServer version 5.6.5 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP OUTPUT=PDF OUTPUT=SWF OUTPUT=SVG 
     SUPPORTS=PROJ SUPPORTS=AGG SUPPORTS=FREETYPE SUPPORTS=ICONV SUPPORTS=FRIBIDI SUPPORTS=WMS_SERVER 
     SUPPORTS=WMS_CLIENT SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT SUPPORTS=WCS_SERVER SUPPORTS=SOS_SERVER 
     SUPPORTS=FASTCGI SUPPORTS=THREADS SUPPORTS=GEOS SUPPORTS=RGBA_PNG SUPPORTS=TILECACHE INPUT=JPEG 
     INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE

Step 2: Verify That Your Files' Encoding is Supported by ICONV
--------------------------------------------------------------

Since MapServer uses the libiconv library to handle encodings, you can check the list of supported encodings 
here: http://www.gnu.org/software/libiconv/

Unix users can also use the *iconv -l* command on a system with
libiconv installed to get the complete list of supported encodings on
that specific system. 

Step 3: Add ENCODING Parameter to your LABEL Object
---------------------------------------------------

Now you can simply add the ENCODING parameter to your mapfile LAYER object, such as:

.. code-block:: mapfile

   MAP
    ...
    LAYER
      ...
      CLASS
        ...
        LABEL
          ...
          ENCODING "SHIFT_JIS"
        END
      END
    END
   END


One of the benefits of having an "ENCODING" parameter within the LABEL object is that different LAYERS with different encoding systems can be combined together and display labels within a single map.  For example, labels from a Layer using Shapefile as it source which contains attributes in SHIFT-JIS can be combined with a Layer from a PostGIS database server with EUC-JP attributes.
A sample Mapfile can look like this:

.. code-block:: mapfile

   LAYER
     NAME "chimei"
     DATA chimei
     STATUS DEFAULT
     TYPE POINT
     LABELITEM "NAMAE"
     CLASS
       NAME "CHIMEI"
       STYLE
         COLOR 10 100 100
       END
       LABEL
         TYPE TRUETYPE
         FONT kochi-gothic
         COLOR 220 20 20
         SIZE 10
         POSITION CL
         PARTIALS FALSE
         BUFFER 0
         ENCODING SJIS
       END
     END
   END

   LAYER
     NAME "chimeipg"
     CONNECTION "user=username password=password dbname=gis host=localhost port=5432"
     CONNECTIONTYPE postgis
     DATA "the_geom from chimei"
     STATUS DEFAULT
     TYPE POINT
     LABELITEM "NAMAE"
     CLASS
       NAME "CHIMEI PG"
       STYLE
         COLOR 10 100 100
       END
       LABEL
         TYPE TRUETYPE
         FONT kochi-mincho
         COLOR 20 220 20
         SIZE 10
         POSITION CL
         PARTIALS FALSE
         BUFFER 0
         ENCODING EUC-JP
       END
     END
   END 

Step 4: Test with the shp2img utility
-------------------------------------

- see :ref:`shp2img commandline utility <shp2img>`

Example Using PHP MapScript
===========================

For PHP Mapscript, the *Encoding* parameter is included in the LabelObj Class, so that the 
encoding parameter of a layer can be modified such as:

::

    // Loading the php_mapscript library
    dl("php_mapscript.so");

    // Loading the map file
    $map = ms_newMapObj("example.map");

    // get the desired layer
    $layer = $map->getLayerByName("chimei");

    // get the layer's class object
    $class = $layer->getClass(0);

    // get the class object's label object
    $clabel= $class->label;

    // get encoding parameter
    $encode_str = $clabel->encoding;
    print "Encoding = ".$encode_str."\n";

    // set encoding parameter
    $clabel->set("encoding","UTF-8"); 


Notes
=====

During initial implementation, this functionality was tested using the different Japanese encoding systems: 
Shift-JIS, EUC-JP, UTF-8, as well as Thai's TIS-620 encoding system.