Image Acquisition

Abstract

Images of one form or another provide a significant source of information for GIS. As the development of multimedia technology matures, the integration of images into a GIS environment has become more important. Images can be classified in many different ways, such as by their type (digital or analogue), by the imaging device used to capture them (frame camera or linear scanner), or by the imaging platform that carried the device (aircraft or spacecraft). Section 9.2 discusses the two types of images-digital and analogue. Section 9.3 describes the different types of imaging devices-cameras and scanners. Scanners are divided into two types, those that convert analogue images to digital and those that capture the digital image in real time. Factors specifically relating to air-borne imagery — those taken from aircraft typically with large and medium format cameras (often referred to as aerial photogrammetry) — are addressed in section 9.4, while section 9.5 discusses imagery obtained from space-borne sensors. This imagery typically comes from real-time scanning systems and is known as satellite remote sensing.