Publication Date

1989

Description

For compilation of Grassland Ressource Map of China (GRMC), it was necessary first of all to collect reliable data which is accurate and fairly up-to-date. A national standard of grassland classification and legend system must be worked out. Content, method and level of representation must be made standard. Criteria must be set for integration, inclusions or omissions in the map units. China's vast grasslands stretch over areas totalling 1,5 billion hectares. No standard survey had been carried out before. Basic data and maps needed for compilation of GRMC on scale 1 : 1,000,000 was lacking. Thus beginning in 1979, large­scale surveys were carried out under a standard procedure in over 1,600 counties where grasslands are found. The main method was using topographic maps on a scale of 1 : 50,000 as base maps (for pastoral counties, the scale is 1 : 100.000), mak­ing field trips for investigations, mappings, and measuring grassland yields. Supplementary measures included checking with airphotos. Thus were produced maps of grassland types, grassland class/grade and state of grassland utilization on scales of 1 : 50,000 (county level), 1 : 100,000 (pastoral county level), 1 : 200,000 (regional level) and 1 : 500,000 (provincial level). Finally GRMC was produced by minimizing the above­mentioned three types of 1 : 500,000 scale provincial maps.

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Compilation and Study of Grassland Resource Map of China (Scale- 1: 1,000,000)

For compilation of Grassland Ressource Map of China (GRMC), it was necessary first of all to collect reliable data which is accurate and fairly up-to-date. A national standard of grassland classification and legend system must be worked out. Content, method and level of representation must be made standard. Criteria must be set for integration, inclusions or omissions in the map units. China's vast grasslands stretch over areas totalling 1,5 billion hectares. No standard survey had been carried out before. Basic data and maps needed for compilation of GRMC on scale 1 : 1,000,000 was lacking. Thus beginning in 1979, large­scale surveys were carried out under a standard procedure in over 1,600 counties where grasslands are found. The main method was using topographic maps on a scale of 1 : 50,000 as base maps (for pastoral counties, the scale is 1 : 100.000), mak­ing field trips for investigations, mappings, and measuring grassland yields. Supplementary measures included checking with airphotos. Thus were produced maps of grassland types, grassland class/grade and state of grassland utilization on scales of 1 : 50,000 (county level), 1 : 100,000 (pastoral county level), 1 : 200,000 (regional level) and 1 : 500,000 (provincial level). Finally GRMC was produced by minimizing the above­mentioned three types of 1 : 500,000 scale provincial maps.