HJ satellite based mapping technologies of land use products for emergency response of agricultural disasters

Accurate and reliable information on land use is a basis of agricultural disaster warning and emergency action. The natural disasters typhoon, cold disaster, drought, and so on, have great influences on agricultural production in Guangdong Province, China. Through literature analysis at home and abroad, it was pointed out that Chinese HJ satellites have become important sources of remote sensing images due to short imaging period and broad coverage (about 2 days and 700km). It also advances the free sharing of OLI data on the new generation of remote sensor of Landsat. Considering the severe orbit deviation and frequent phenology changes of agricultural land use, this paper described and laid emphasis on the necessity and perspective of developing multi-scale (1:500,000, 1:20,000, 1:50,000) agricultural land use products of Provincial-City-County within Guangdong through the usage of relatively fixed ground control point database and spectral library based advanced hierarchical classification technologies supported by HJ satellite data. Such a tendency of quick disaster emergency response for land use dynamic implies a technological focus on the usage of above-mentioned advanced HJ satellite technologies. Based on Landsat images, we also built the 11 united ground control points (40 points at most for whole Guangdong Province) and standardized the technology system of land use remote sensing mapping with the combination of spectral library-based hierarchy classification technology. Selected key technologies for enhancing land use production mapping efficiency and accuracy that involve Landsat OLI and HJ satellites are presented and discussed. The HJ satellite is an effective information source for land use dynamic mapping under emergency action such as disaster damage evaluation, which can provide a short imaging period with wide spatial coverage and enhance the ability of land use data acquirement from one to three or four times or so in one year. The building of relatively fixed ground control points increase the efficiency of province-level land use mapping from one week to two days. The proposed method is especially useful for the development of land use products in cloudy and rainy south China.