question about the map of China

I want to convert the map of China(osm format, from http://download.geofabrik.de/osm/ ) into .rdm file and use it in the opensource GPS software ROADMAP. But there is something wrong when I do that. The map roadmap shows is not correct, only a few cities in the west part can be found, besides that there are only messy roads. I have built the map several times. So I think the .osm file I download maybe is not reliable, because I tried other osm maps from that website, which are all good. So I want to askļ¼š
1)Are there some defects with the file: http://download.geofabrik.de/osm/asia/china.osm.bz2
or
2)what mistake did I make when I converted the map file using the Roadmap tool buildmap_osm?
my Email: gangliu@ambarella.com
waiting for reply!Thank you very much!

Hi, I am not familiar with the ROADMAP tool. Did you compare result with the MAPNIK map from OSM: http://www.openstreetmap.org/?lat=37.11&lon=84.41&zoom=6&layers=B000FFF

the amount of data is extremely low in the west of China. That has nothing to do with the geofabrik download but very few people have been there to create the data.
I checked in a different way (JOSM) the data base around Kashgar and that looks consistent with the Mapnik map, so you can use the Mapnik result as a basis for comparison.

Interesting to hear if there is an active OSM community in China.

Success mapping, Hugo

The problem has been solved. Thank you very much for you reply!