An Automated Method for Digitizing Color Thematic Maps

There is an increasing need for methods of rapidly entering analog data into geographic information systems. Traditional methods of hand digitizing or hand tracing followed by scanning are costly and time consuming. We have developed a rapid, easy to use method for digitizing color thematic maps that makes use of standard image processing techniques. The method uses a digital camera followed by supervised spectral classification and post-classification smoothing. Although overall accuracy for an extremely challenging test map was 93 percent, our results indicate that for most applications expected accuracy is very high.