General image manipulation functions in a geographic information system

Historically, potential computer users with wide ranges of applications have found the computer very complex and difficult to use. In addition, their prohibitive costs have driven away many people who could have used them. Newer computers are even more complex, but they tend to be easier and cheaper to use. As such, their range of applicability has increased dramatically. Where the first computer was used to solve very demanding and time-comsuming scientific ballistic applications, today's computers are used in scientific applications, in business applications, and even in automobiles and washing machines. The large number of areas in which computers are being introduced is partly due to the availability of computers which can do the application. However, in some instances, it is the nature of the application that creates the demand for a computer to do the job. For instance, some jobs, such as very large payroll or inventory systems, are very cumbersome and error prone if done manually. The amount of data is simply too much for a human staff. One specific example of an application where computers are becomming necessary is in the area of geographic information processing. Computerized geographic information processing is a logical development in the use of location-specific data. Location specific data is information that is concerned with, or can be distributed over, land areas. Examples of this are land ownership, use, and population. All of these examples of location specific data have traditionally been done by hand. The involvement of computers into these areas was caused by the bulk of data and its need to be easily and quickly retrieved. Moreover, the data for land ownership, which may come from county records, the population data, which may come from the census bureau, and other data such as land use and cover must be frequently merged and manipulated together in a manner which would be very impractical if done manually. This is now beginning to change with the advent of computerized geographic information processing. Several local, state, and federal agencies are now developing, or have recently developed, systems for their own use. The data for the systems has come from both ground-truth and aerial photographs as well as from existing information. Since the launch of the Landsat satellite series, new information is becoming available at a staggering rate. For example, a scene of Landsat data covers an area of about 185 by 185 kilometers square. Only …