Method for printing large map at client side based on Flex

The invention discloses a method for printing a large map at a client side based on Flex, belonging to the technical field of geographic information. According to the invention, dynamic selection of a map printing range can be carried out in multiple manners (such as circular selection, rectangular selection, polygonal selection and administrative region selection) by utilizing an API at a Web client side; and screenshot printing at the client side based on FLEX is carried out in combination with the scale of a map to be printed. By means of the method, the map at the client side is subjected to dynamic translation and screenshot joint by monitoring a graphic layer updating event at a WebGIS client side and taking the size of a current screen as the unit; for the jointed map, two manners including a manner of printing in real time and a manner of deriving to a local picture can be selected; and thus, the problems that a printing graphic layer is limited and the printing length is limited due to the service-ba