GIS allows us to view, understand, question, interpret, and visualize data in many
ways that reveal relationships, patterns, and trends in the form of maps, globes,
reports, and charts.
This project helps you answer questions and solve problems by looking at your data
in a way that is quickly understood and easily shared.
Map Where Things Are
Mapping where things are lets you find places that have the features you're
looking for and to see patterns.
People map quantities to find places that meet their criteria and take action. Public
health officials might want to map the numbers of physicians per 1,000 people in
each census tract to identify which areas are adequately served, and which are not.
A density map lets you measure the number of features using a uniform areal unit
so you can clearly see the distribution. This is especially useful when mapping
areas, such as census tracts or counties, which vary greatly in size. On maps showing
the number of people per census tract, the larger tracts might have more people
than smaller ones. But some smaller tracts might have more people per square mile—a
Find What's Inside
Use GIS to monitor what's happening and to take specific action by mapping what's
inside a specific area. For example, a district attorney would monitor drug-related
arrests to find out if an arrest is within 1,000 feet of a school--if so, stiffer
Find What's Nearby
GIS can hrelp you find out what's occurring within a set distance of a feature
by mapping what's nearby.
Map the change in an area to anticipate future conditions, decide on a course of
action, or to evaluate the results of an action or policy. By mapping where and
how things move over a period of time, you can gain insight into how they behave.
For example, a meteorologist might study the paths of hurricanes to predict where
and when they might occur in the future.
Data restructuring can be performed by a GIS to convert data into different formats.
For example, a GIS may be used to convert a satellite image map to a vector structure
by generating lines around all cells with the same classification, while determining
the cell spatial relationships, such as adjacency or inclusion. More advanced data
processing can occur with image processing, a technique developed in the late 1960s
by NASA and the private sector to provide contrast enhancement, false colour rendering
and a variety of other techniques including use of two dimensional Fourier transforms.
Since digital data is collected and stored in various ways, the two data sources
may not be entirely compatible. So a GIS must be able to convert geographic data
from one structure to another.