CAD file conversion to GIS layers: Issues and solutions

CAD data created for drawings and Geographic Information System (GIS) data are created for different purposes. As a result the software´s data models are inherently different, and the files differ in their structure and attributes. CAD data contain information to draw it with features organized by mixed layers. While GIS data has an additional functionality, its feature can hold huge amounts of data describing the features. Moreover, GIS data is “spatially informed” regarding adjacency and other spatial relationships. Thus, the conversion of CAD files to GIS shape file may face problems and data may get corrupted. Furthermore, in order to keep the geometric properties integrity and accuracy, we should be able to keep a correct topological database. Accurate topological data leads to correct and reliable spatial analysis, in addition to cost reduction. The aim of the topological knowledge in GIS is to increase spatial analysis opportunities. Hence, we should be able to evaluate a topological database, in addition to the geometric properties. Different issues will be addressed in this work; a step-by-step methodology will be presented using a case study to demonstrate the problems, and provided solutions using different software and programs. Examples of problems and solutions when transferring CAD data into GIS data layers are provided to allow correct and full functionality of the GIS.