Production of Digital Mosaics from Aerial Images

Abstract

This research deals with the mosaicking aerial images using Geographic Information System ( GIS ) . The digital mosaic is assembled from two strips of aerial images. Each strip consists of four images of Jadria in Baghdad city ( Iraq ) at scale ( 1 : 3000 ) . Three methods of mosaics are implemented and compared : controlled , uncontrolled and semicontrolled mosaics . The controlled mosaic is produced from Ground Control Points ( GCPs ) located in the study area . Eighteen control points are selected at the optimum locations ensure the required distribution and strength of mosaics . The coordinates of GCPs are measured using Total Station instrument. Images are georeferenced to ground control points using ArcGIS 9.3 . Uncontrolled mosaic is prepared by matching the image details of adjacent images . Semicontrolled mosaic is assembled utilizing some combinations of the specifications for controlled and uncontrolled mosaics . The controlled mosaic is the accurate methods. All images must have the same number of bands , the same spatial reference and the same pixel size ; otherwise the mosaic cannot be created . Digital mosaic is extremely useful for preparing updating maps used in engineering projects.