Wetland resource investigation of the north suburban of the Zhangye City Based on the Airborne CCD images

摘要

The CCD images were obtained during the intensive observation period of the Watershed Allied Telemetry Experimental Research. 49 scenes of CCD images with 1-m spatial resolution were used for the pre-processed and investigation on the north suburban wetland resource for the Zhangye City. The pre-processing includes radiometric correction, preliminary geometric correction, preliminary image mosaicing, offset position processing, color matching, differential GPS measurement of the Ground Control Points, geometric precision correction. The image mosaicing exists a series of problems. The biggest problem is the disagreement of the hues. The software of Geoway ColorPro was used to match the colors. The manual interpretation method was applied to extract the patch boundary and type from the mosaiced image. Some questionably patch types were confirmed based on the field investigation. Three main conclusions can be obtained according to the investigation. Firstly, the wetland patches are more fragmentized than the patches of the other land use types. Secondly, the wetland area occupies 45.8 percentages of the total investigation area. The first three wetland types are herb swamp, forest and shrub, and Inland salt marsh. Finally, the investigation results were widely applied to the different departments of the local government.