According to the legend information, in view of the different characteristics of the color, shape, texture and
spatial relationship of various elements on a geological map, techniques of color segmentation, boundary tracking, and mode identification are adopted to extract the main information, e.g. stratum, magmatite, construction, or ore occurrence, related to mineral products in the geological map to form a thematic information graph layer. The geological map thematic
information extraction method includes a geological map data preprocessing method, a geological map thematic
information extraction method, and an information output method. The method aims to solve the difficulty in geological map
information extraction, namely, takes a semi-structured standard geological map as a
research object and the geological map information extraction as objective, and extracts the main information, e.g. stratum, magmatite, construction, or ore occurrence, related to the mineral products in the geological map through the combination with legend information to construct the thematic information graph layer, thereby forming a set of techniques for converting the semi-structured data (image)
into structure data.