Geographic Information Systems

Geographic Information Systems

If the latest GIS systems can convert vector data into raster form and vice versa, is it now irrelevant to maintain a distinction between vector and raster GIS?

Despite the ability of nearly all GIS and CAD/CAM systems to complete vector-to-raster conversions and vice versa, there still exists the need for keeping vector-based and raster-based data separately managed and stored. There are inherent differences between vector and raster data, each with specific attributes necessary for completing effective GIS-based data analysis. The intent of this short essay is to explain why it is still very relevant to keep a distinction between vector and raster-based GIS data.

One of the most prevalent uses of vector-based data in GIS and CAD/CAM systems is providing data and file compatibility to other design and drafting systems and applications. Vector data's inherent characteristics of being able to define X, Y coordinates and the use of quadrants to define relative locations of vector data in a design plane is critical for the development of proposed building, production plant, or larger projects that require the eventual integration of raster data to define which aspects of a project are accomplishable or not.

Vector-based data is invaluable in defining a series of points or nodes throughout multiple layers of as design file, making the computation of points, lines, curves, arcs, polygons and more graphics primitives usable in a Cartesian coordinate pair design space. The multiple layering of AutoCAD and other CAD/Cam applications that work in conjunction with GIS systems are a case in point. Vector-based data can be used for extensive calculations and the definition of complex geometric shapes and conceptual maps relatively quickly due to the majority of vector-based design standards having a set of graphics primitives included as a basic part of their command sets and Application Programmer Interfaces (APIs). In the context of GIS, vector-based data executes more efficiently than raster data and is therefore considered less computationally intensive. This level of computational performance is achieved however due to the much more complex data structure that vector-based design files rely on to store their data points and graphic primitives.

Taking the perspective of having raster data separated from vector data, the many applications of raster-based data in GIS that are made possible through the representation of data as pixels that can be multiple bytes deep in terms of context and color. In addition, pixels that comprise a raster image are organized into grid sizes, grid resolutions, and rely on extensive georeferencing. Raster-based data is captured both from large-scale photography from airplanes in addition to the satellite imagery. While raster-based image data has a relatively simple data structure, is compatible with remotely sensed and scanned data, and has relatively simply spatial analysis features, raster data sets require greater storage space, projection transformations are made more difficult as this imaging technology does not rely on a coordinate space like vector and it is much more difficult to represent relationships with the data as a result. In summary, vector and raster data need to be kept separate due to their inherent unique contributions each provides to GIS-based analysis. Each makes a unique contribution to the development of GIS imagery analysis and systems development.

How does the "human factor" enter into GIS development and implementation?

The human factor relates to the aspects of changing how designers, engineers, and researchers apply recently introduced GIS systems' new features and functions to their existing jobs. The introduction of a GIS system that is first defined through the development and implementation of the applications all based on defining and then re-designing the processes by which GIS systems users will be able to do their jobs more efficiently is at the center of the human factors associated with GIS systems. Commonly referred to as change management, human factors are the study of how processes can be made more efficiently by the selective development and integration of GIS systems-based components and applications.

At the center of the human factor of GIS systems development and implementation is the resistance to change that many of those who will ultimately benefit from the system show on a consistent basis. The fact that resistance and fear of change makes more GIS system implementations fail than any company or organization would care to admit underscores how critical of an issue this is for any organization looking to roll out a GIS system. Overcoming resistance to change is the greatest challenge of all in terms of the human factors if GIS system development and implementation. The tendency is for people to see a new system as a potential replacement of their role and the fear of their importance somehow being lessened or made less important dominates their minds. Overcoming the fear of change and attempting to lead those more affected and paradoxically with the most to gain from a new GIS system design and implementation is the foundation of change management theories used throughout organizations.