VO-IMPAT:Image Processing and Analysis Toolkit for the Virtual Observatory of China

The Image Processing and Analysis Toolkit for the Virtual Observation(VOIMPAT) of China,developed at National Astronomical Observatories,is a service providing simultaneous access to images of the Digital Sky Survey(DSS),astronomical catalogues,and other databases.The devising aim of VO-IMPAT is to federate multi-band astronomical data and to overlay catalogues from different bands upon the image of DSS,such as USNO,2MASS,NVSS,RASS catalogues.At present the aim has been realized.VO-IMPAT provides many essential image processing functions,which include zooming in and out,changing color-maps,contours,drawings,histogram,smooth,sharpen,rotate,tag and so on.Moreover different catalogues can be displayed with dissimilar colures and symbols.