switch2osm使用open street map离线地图中文乱码方框解决办法
----------written by shenwenkai-------------
ubuntu linux环境下，按照网址（https://switch2osm.org/serving-tiles/building-a-tile-server-from-packages/提供的方式，执行至sudo /etc/init.d/renderd restart
打开http://localhost/osm/slippymap.html就可以看到样例图；但是如果不出意外，中文会出现方框，无法正常显示。
下面说明解决方法：
- 1）安装unifont字体
sudo apt-get install unifont
- 2）修改/etc/mapnik-osm-data/inc/fontset-settings.xml.inc的内容为：
<!--Settings for Mapnik Fonts
To see the fonts you have installed with Mapnik do:
ls `python -c "import mapnik;print mapnik.fontscollectionpath"`-->
<FontSet name="book-fonts">
<Font face-name="unifont Medium" />
</FontSet>
<FontSet name="bold-fonts">
<Font face-name="unifont Medium" />
</FontSet>
<FontSet name="oblique-fonts">
<Font face-name="unifont Medium" />
</FontSet>
修改/etc/renderd.conf的内容为：
[renderd]
stats_file=/var/run/renderd/renderd.stats
socketname=/var/run/renderd/renderd.sock
num_threads=4
tile_dir=/var/lib/mod_tile ; DOES NOT WORK YET
[mapnik]
plugins_dir=/usr/lib/mapnik/2.0/input
font_dir=/usr/share/fonts/truetype/unifont
font_dir_recurse=true
[default]
URI=/osm/
XML=/etc/mapnik-osm-data/osm.xml
DESCRIPTION=This is the standard osm mapnik style
;ATTRIBUTION=©<a href=\"http://www.openstreetmap.org/\">OpenStreetMap</a> and <a href=\"http://wiki.openstreetmap.org/w\
iki/Contributors\">contributors</a>, <a href=\"http://creativecommons.org/licenses/by-sa/2.0/\">CC-BY-SA</a>
;HOST=tile.openstreetmap.org
;SERVER_ALIAS=http://a.tile.openstreetmap.org
;SERVER_ALIAS=http://b.tile.openstreetmap.org
;HTCPHOST=proxy.openstreetmap.org
- 3）修改/etc/mapnik-osm-data/osm.xml的关键词，把配置文件中的FontSet name="bold-fonts"等字体集设置全部改为字符类型设置face-name="unifont Medium"。
- 4）删除缓存文件 sudo rm -rf /var/lib/mod_tile/default/*
再次打开，中文名称应该就可以正常显示了。
附加：
可以根据如下命令的运行情况，来判断mapnik是否正确运行。
sudo su www-data
$ renderd –f
renderd[26014]: Rendering daemon started
renderd[26014]: Parsing section renderd
renderd[26014]: Parsing render section 0
renderd[26014]: Parsing section mapnik
renderd[26014]: Parsing section default
renderd[26014]: config renderd: unix socketname=/var/run/renderd/renderd.sock
renderd[26014]: config renderd: num_threads=4
renderd[26014]: config renderd: num_slaves=0
renderd[26014]: config renderd: tile_dir=/var/lib/mod_tile
renderd[26014]: config renderd: stats_file=/var/run/renderd/renderd.stats
renderd[26014]: config mapnik: plugins_dir=/usr/lib/mapnik/2.0/input
renderd[26014]: config mapnik: font_dir=/usr/share/fonts/truetype/unifont
renderd[26014]: config mapnik: font_dir_recurse=1
renderd[26014]: config renderd(0): Active
renderd[26014]: config renderd(0): unix socketname=/var/run/renderd/renderd.sock
renderd[26014]: config renderd(0): num_threads=4
renderd[26014]: config renderd(0): tile_dir=/var/lib/mod_tile
renderd[26014]: config renderd(0): stats_file=/var/run/renderd/renderd.stats
renderd[26014]: config map 0: name(default) file(/etc/mapnik-osm-data/osm.xml) uri(/osm/) htcp() host()
renderd[26014]: Initialising unix server socket on /var/run/renderd/renderd.sock
renderd[26014]: Created server socket 5
renderd[26014]: Renderd is using mapnik version 2.0.0
renderd[26014]: DEBUG: Loading font: /usr/share/fonts/truetype/unifont/unifont.ttf
Running in foreground mode...
renderd[26014]: Starting stats thread