Study On Plant Measurement Based On Aeroscape In Desert

Forestry mapping and plant surveying by aeroscape are main tasks of plant resources investigation. Base on the theory of bundle aerotriangulation, Using OrthoBASE module of ERDAS software, 130 digital airscapes consisted of 10 strips were orthorectified by GPS-supported Aerial Triangulation. Those were shoot in the Wu Lan Bu He Desert in Inner Mongolia in 2006. Then we obtained 1 sq km area images (1:1000 scale), and Image resolution is 0.1m. This is the first time that through digital aerial photograph system by PPP(Precision Point Position) navigation generated orthophoto image in China forestry. Image displacement caused by camera tilt and terrain fluctuation is eliminated or reduced greatly. And image errors mainly caused by camera lens distortion photographic material deformation atmospheric refraction and earth's curvature are eliminated or reduced greatly. Digital aerial photograph system by PPP(Precision Point Position) navigation has shorter production cycles, highly accuracy map, no ground control points outside the workload, so it can carry out in atrocious weather such as desert, cold and high latitude areas, and suffice the needs of digital forestry in those areas.We measured indicators of Nitraria tangtorum and Elaeagnus angustifolia included east-west and north-south crown ranges, height and circumference by using the production of orthophoto image and shadow-based altimetry. Though the analysis of measurement precision, we concluded, the relative error is 20%, which fall in the range of precision in desert plants survey.