Basic Scale Topographic Mapping
1. Surveying & mapping of basic scale topographic map
China national basic scale topographic map is a full-element topographic map plotted or compiled according to the specifications of surveys, diagrams and scale system published by China. The national basic scale topographic map mainly consists of 11 scales including 1:500, 1:1000, 1:2000, 1:5000, 1:10k, 1:25k, 1:50k, 1:100k, 1:250k, 1:500k and 1:1 million. Of which, the mapping and updating of 1:1 million-1:250k national basic scale topographic maps are implemented by state-level competent department of surveying & mapping administration; the mapping and updating of 1:10k -1:5000 national basic scale maps are implemented by the competent department of surveying and mapping administration of the people’s governments of provinces, autonomous regions and municipalities; while the mapping of and updating of 1:2000-1:500 national basic scale maps are implemented by the people’s government of city with sub-district or county according to law.
In recent years, China has accelerated mapping of basic scale topographic maps, as a result, the coverage and up-to-date state of basic scale topographic map have been improved significantly and the quantity of the map has been increased rapidly. 1:1 million, 1:500k, 1:250k, 1:100k, 1:50k topographic maps have covered the entire land territory of China. The mapping and updating of 1:10k topographic maps have made great headway and covered over 50% of the total territorial area of China, of which 17 provinces, autonomous regions, municipalities and cities specifically designated in the state plan have been completely covered. The coverage of maps with the scale of 1:2000 and above for the built-up areas in 19 provinces, autonomous regions, municipalities, cities specifically designated in the state plan has exceeded 60%; the coverage of maps with the scale of 1:2000 and above for built-up areas in cities above the county level in 4 provinces and municipalities is 100%; and the coverage of high-resolution fundamental geographic information for the built-up areas in cities above the county level of 10 plus provinces is 100%. In 2009, China started surveying and mapping of sea islands (reefs).
2. Construction of the fundamental geographic information database
Since the 1990s, China has strived to organize and carry out construction and updating of its fundamental geographic information database and has so far completed national 1:4 million, 1:1 million, 1:250k and 1:50k fundamental geographic information databases and national geodetic surveying database; construction and updating of 1:10k fundamental geographic information database have been carried out in 30 provinces (autonomous regions, municipalities) across China. Thanks to the abundant fundamental geographic information data and improved up-to-date state, a multi-factor, multi-scale and multi-temporal fundamental geographic information data resources network has taken in shape. China updated its national 1:250k fundamental geographic information database twice, and the up-to-date state of data reached the level of the year of 2007; it updated the national 1:50k fundamental geographic information database and the up-to-date state of data reached the level of the period from 2006 to 2010. The data content became richer, shifting from core topographic features to full-element data and fully adopting the advanced national geodetic coordinate system 2000.
Since 2013, China has started to update its national fundamental geographic information database dynamically and updated the information including geographic name, boundary and transportation and so on rapidly, and planned to launch new version of the database annually. The coordinated updating mechanism of 1:250k and 1:50k fundamental geographic information databases has been established.
In terms of the construction of provincial 1:10k fundamental geographic information database, provincial 1:10k fundamental geographic information has covered a land area of approximately 4.62 million square kilometers. 80%~100% of the total area of 11 provinces (autonomous regions, municipalities) have been covered by 1:10k data; and 50%~80% of the total area of 5 provinces are covered by 1:10k data. Between 2006 and 2010, the first-generation 1:10k fundamental geographic information databases were updated in one third of the provinces (autonomous regions, municipalities) in China.
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