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Lots of metrics confirm that China is expanding at an impressive rate. ISPRS participants on a technical visit to the the National Geomatics Centre of China were given some more: when NGCC's 1:1 million coverage was updated in 2003, cartographers discovered they had to change 8 per cent of the political boundaries, 14 per cent of the railways, 23 per cent of the residential areas and 37 per cent of the roads.

The NGCC was established in 1995 with a mission to create a digital map of China. It responded with a series of mapping programs at scales of 4 million, 1 million, 250,000 and 50,000. Larger scale mapping, all the way down to 1:500 scale, exists for certain areas, but is undertaken by provincial or municipal authorities.

The databases were originally no more than digitised maps. However, over the years, they have all been updated using a variety of technologies, especially satellite imagery. This imagery is mainly sourced from Landsat's Thematic Mapper and the Spot satellites.

The 1:1 million map series was completed in 1993. It was used to generate a digital elevation model with 600 metre postings.

The 1:250,000 series was completed in 1998. An update program was completed in 2002.

The 1:50,000 series was finished in 2005. It is composed of 24,322 map sheets. An update program started in 2006 was used to derive a digital elevation model with 25 metre postings, the best available for China.

Each database is organised into five themes: geodetics, topographic, imagery and thematic. The thematic theme contains datasets covering administrative boundaries and transport routes.

Apart from the map databases, NGCC also maintains the National Geodetic Database, with its origin in Xi'an. There is a national high precision network consisting of 300 Level A points and 2500 Level B points.

NGCC also runs the National Gravity Network and the Crustal Movement Monitoring Network. The latter is based on 1200 GPS stations.

Data from these sources is available for the cost of distribution. However, potential users require a certificate before NGCC will accept an order for anything larger than 1:1 million scale. For Chinese citizens, this is evidently not much of a problem. Senior engineer Li Li told the group that school teachers, for instance, could obtain the data for educational purposes.

NGCC also has plans for an English language website, although no date has been established for its completion. The plan is that all annotation on the maps will use western lettering.

In the immediate future, NGCC will devote considerable resources to supporting plans for the development of China’s west. It is currently undertaking the mapping for an ambitious scheme to pump water from the south up to the deserts of the north.

The organisation is also developing programs to better understand the desert environment so new development can occur with minimal ecological damage.

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