GIS contains spatial data (unlike other information systems).  Spatial data includes coordinates that define geographic objects.  Geodesy was mentioned in the last post. Geodesy is “the science of measuring the shape of the Earth (Bolstad).”  Because it’s hard to perceive the curvature of the Earth on a human scale, we’ve been using flat maps for the majority of our lifetime.  Flat maps distort geometry due to not being able to take into consideration the curvature of the Earth.

A flat map complicates defining coordinates because measurements are affected by the distortion created by flat maps.  The irregular shape of the Earth and imperfect measurements also complicate the defining of coordinates.  Earth is not a perfect sphere shape and is actually very deformed because of natural forces.  Our measurements contain error but with improvements over time and with the sophistication of models, our measurements of positions on Earth improve.

All these differences in defining coordinates cause us to create “several sets of coordinates that define the same location on Earth (Bolstad).”  The points created at a location on Earths’ surface are coordinates that depend on how the points from a flat map are translated onto a curved map surface, what type of reference is used in creating the coordinates and what shape of the Earth is taken into consideration when formulating the measurements for the points.





Bolstad, Paul. (2012).  GIS Fundamentals:  A First Text on Geographic Information Systems.  White Bear Lake, MN:  Eider Press.


New Developments in GIS

            Any changes in the GIS field are based on advancements made in computers, electronic hardware, high speed connections (wireless or wired), and increased intricacy in GIS software and users. Global Navigating Satellite System (GNSS) will change with improved GNSS-receivers, miniaturization of GNSS technology, and system integration.

            GNSS receivers will continue to decrease in price, shrink in size, and increase accuracy, making the technology more appealing to use.  Chip GNSS systems have been getting smaller, some are smaller than the size of a single postage stamp.  These small devices will be able to be easily incorporated into electronic devices such as wrist-watches, allowing outdoor enthusiasts (hikers, runners, and bicyclists) to monitor their location, speed, route, and log miles travelled.  GNSS miniaturization allows the ability to collect more data in the field than in the past.  New systems will add functions to GNSS such as the ability to take photos or videos of a feature, this could allow companies (i.e. utility companies) to easily identify a problem and identify the tools and/or parts that are needed to correct the problem.

            Continents are moving around the Earth on tectonic plates, sometimes at rates of an inch per year (or faster!)  This movement leads to the changes of relative positions over several decades.  Geodesists (a scientist or a technician who engages in inquiry or applies research in the field of geodesy (Bolstad)) must factor in the movements to improve datums (NAD83 and ITRF).  NAD83 is a datum used mostly in North America while ITRF is a datum used by the rest of the world.  Both these datums are Earth-centered systems based on the coordinate location of points and their velocities. 

            Improved remote sensing includes more satellites, higher spatial and temporal resolution, improved digital cameras, and new sensor platforms (Bolstad).  The Pleiades system is an example of this trend of improvements; these two satellites provide daily panchromatic and multispectral imaging.  Aerial cameras are also improving in spatial resolution with higher radiometric sensitivity.  These higher spatial resolutions will aid in many new accomplishments; detailed land surveys, property and asset management, business intelligence, strategic planning, and much more.




Bolstad, Paul. (2012).  GIS Fundamentals:  A First Text on Geographic Information Systems.  White Bear Lake, MN:  Eider Press.

Another Introduction to GIS

There are several definitions used while explaining geographic information systems (GIS).  One of the most popular definitions for GIS is “a computer-based system to aid in the collection, maintenance, storage, analysis, output, and distribution of spatial data and information. (Bolstad)”  GIS helps us gather and use spatial data;  it is concerned with absolute and relative location of features (the where) and it’s concerned with properties and attributes of those features (the what).

GIS quantifies locations by recording their coordinate positions on Earth (latitude/longitude).  GIS tools are essential in business, government, education, and non-profit organizations (Bolstad).  It helps us identify and address environmental problems by providing information on where the problems occur and who are affected by them.  Using GIS we are able to identify the source, location, and extent of environmental impacts.

Advances in three key technologies have helped aid in the development of GIS; imaging, GNSS, and computing.  Cameras these days provide detailed aerial and satellite images, images can be easily converted to accurate spatial information over broad areas.  Global Navigation Satellite Systems (GNSS) is a positioning technology that’s now incorporated in cars, planes, boats, and trucks. Powerful field computers are now lighter, faster, more capable, and less expensive, allowing spatial data display and analysis capabilities to always be at hand.

Geographic information science (GISci) includes the technical aspects of GIS as well as seeks to redefine concepts in geography in the context of the digital age, making GIS dependent on GISci.  GISci not only investigates technical questions but also explores more basic questions, such as, “How might we best represent spatial concepts? (Bolstad)”





Bolstad, Paul. (2012).  GIS Fundamentals:  A First Text on Geographic Information Systems.  White Bear Lake, MN:  Eider Press.