EXPLORING AND EVALUATING THE CONSEQUENCES OF VECTOR-TO-RASTER AND RASTER-TO-VECTOR CONVERSION

Spatial data can be represented in two formats, raster (grid cell) or vector (polygon). It is inevitable that conversion of the data between these two formats be essential to the best use of the data. Most geog raphic information systems (GIS) now provide software for such a conve rsion. The objective of this study was to explore and evaluate the con sequences of data conversion on the accuracy of the resulting data lay er. Simple shapes were chosen to document the results of the raster-to -vector and vector-to-raster conversion processes. These shapes includ ed a square, a triangle (not aligned with the grid), a circle, a hole within the circle, and a non-convex shape. Error matrices were employe d to represent the changes in area through the conversion process. A s econd set of data including a circle, a thin rectangle, and a wide rec tangle were used to examine the effect of grid cell size on both prese nce/absence of a feature as well as to maintain the feature's shape. F inally, recommendations for continuing this work and its application t o information derived from remotely sensed data were presented.