1. An identifying system for automatically identifying a geometrical element in an image, the image being retrieved from an image capturing apparatus and located in a coordinate system, the identifying system comprising: a collecting module for collecting dots from the image as a dot muster and retrieving coordinates of all dots of the dot muster from the coordinate system; a curve fitting and geometrical element identifying module for calculating a line-offset and a circle-offset according to the coordinates of all the dots of the dot muster when three dots or more are included in the dot muster, identifying that the dot muster is a line when the circle-offset is greater than or equal to the line-offset, and identifying that the dot muster is a circle when the circle-offset is less than the line-offset; a storing module for storing the coordinates of all the dots of the dot muster, data produced during the curve fitting process, and result data of curve fitting and geometrical element identifying; a setting module for customizing a style in which the result data is outputted, and choosing to partially or completely output the result data; and an outputting module for outputting the result data.