What is GIS?
GIS is a computer program for storing, retrieving,
analyzing, and displaying data. It combines two kinds of information or
databases. GIS stands for Geographic Information System.
One is geographically referenced information: latitude & longitude
coordinates, spatial or location information, "where things are".
The second is attribute or descriptive information: characteristics or
qualities of that place, "what things are like". Attribute data could be
census information (e.g., population, housing), natural resources (e.g.,
trees, soil types), infrastructure (e.g., buildings, roads) or events
(e.g., # of accidents).
When
the geographic and attribute information are layered or put together,
GIS creates a map to show you what the place is like: where accidents
occur in your community, where teenagers live in your state, etc.
What layers of information you combine depends on your purpose — you
need different information to find the best location for a new soccer
field than you do to analyze the environmental damage from a tornado.
You may use existing data (e.g., census), or create your own (e.g., walk
around your neighborhood and use GPS to record the location of every oak
tree). The information is computerized (scan, keyboard entry) and stored
until you request that it be mapped in the way you define.
Here's a short movie clip about What is GIS..clip
and what is GIS important..clip
What is GPS?
GPS is a navigational system that can accurately
locate your position anytime, anywhere, and regardless of weather on
Earth. Developed by the United States Department of Defense, it uses 24
satellites orbiting the earth at altitudes of approximately 11,000 miles
to transmit data.
The handheld GPS receiver processes data from several satellites to
"triangulate" the receiver's exact location, using latitude and
longitude. Uncorrected positions determined from GPS satellite signals
produce accuracies in the range of 50 to 100 meters. When using a
technique called "differential correction", users can get positions
accurate to within 5 meters or less.
GPS has a number of important applications such as search and rescue
missions, helping pilots avoid collisions, and accurate application of
farm fertilizers and other chemicals. Recreational uses include a
navigational tool for orienteering, hiking, hot air ballooning, boating
and many other activities. GPS provides any point on earth with a unique
address (its precise location).
An important 4-H use of the GPS receiver is to identify or mark the
precise location of things or events in their community that are
important for your project or program, and then enter location
information (e.g., of pine tree, car accident that resulted in 3 deaths,
where nitrogen in the stream exceeds a certain level, etc.).
GPS tells us where while GIS tells us what. Together, they help us
locate, organize, and map our communities.
