What is GIS?
GIS is an acronym for Geographic Information
Systems. What does this phrase mean? Information systems help us manage what we
know by making it easier to organize, store, access, retrieve, manipulate,
synthesize, and apply the information to our benefit. Geographic, describes
where events, activities, and things happen or exist on the face of the earth.
This is a broad definition, and well it should be, because GIS is many different
things to many different people.
General Uses for GIS
- It can be used to simply create maps so that the “where” is
- It can be used to analyze data and relate it to other natural
- It can be used to take advantage of the tremendous amount of
information presented by remote sensed data from aerial photography and
Entomological Uses for GIS
- Map insect populations so we know where they are and are not so
we can work more efficiently and achieve enhanced control with reduced effort.
- Accurately calculate the area we need to treat so we can mix
just the pesticide we need.
- Identify other natural parameters which predict pest
populations. Using parameters which have already been mapped or can be mapped
using remote sensed platforms can reduce our in the field surveillance efforts.
- Relate risk information to others.
Necessary hardware and software
To effectively employ GIS for pest management, tools are needed
for both the field and office.
Requirements for georeferencing data
The key to utilizing GIS is to know, with some degree of
accuracy, where you are on the face of the earth, where your data was collected
from, and how to navigate to specific areas of the earth. Advances in just the
last decade have made this task so much easier, and there are many systems on
the market to choose from. Contact us for recommendations when purchasing a
Requirements for producing pest maps
Some GIS Terms
Layers – GIS produces maps using layers. It is
helpful to think of these as clear sheets with a specific type of information on
them. For instance the first layer of a map may be an outline of the land, the
second waterways, followed by a road layer and a building layer. In GIS programs
layers can be turned on and off and their properties such as color and
Projections – In order to represent the round earth
on a flat surface it is necessary to project the image of the earth. Over the
years many projections have been developed to do this. There are two key points
the GIS novice should be aware of. First, they should collect all their data
using Lat/Long decimal degrees, and Datum WGS1984. Second, they should have a
GIS professional assist them in setting up their GIS project and map and insure
that all the base layers have been converted to the same projection.
Remote Sensed Data – Remote sensed data is
information that has been collected without a human standing at a given point
and making and recording an observation. There are many types of remote sensed
data available today such as airplane and satellite based photography using many
different spectrums, and various types of radar. Resolution of 1 meter or better
is readily available and with this data it is possible to determine species of
vegetation, soil moisture, surface permeability, wetlands, water and soil
temperature, to name just a few. Remote sensing has two advantages, these
platforms can see things humans can’t, such as light in the nonvisible spectrum,
and such data collection is much less expensive than sending people in to record
GIS Helpful Links
There is a wealth of information available on the web about GIS,
how to use it, and where to get data, following are a few sites which provide a
more detailed overview:
The Value of Mapping Pests
Maps have been critical to mankind’s successes.
Frequently “where” is as important, or more important, than “what.” Maps best
answer the question of where and allow us to store and pass this information to
others. The amount, quality, and detail of information which can be mapped have
increased dramatically over just the last few decades. Here are some of the
benefits of mapping pest populations.
Better targeting for pesticide treatments
Mapping allows us to better target our pesticide
treatments or other intervention strategies so we can put our efforts where they
are the most productive. Generally, we have found that 80% of a pest population
is located on just 20% to 30% of an area of interest. Being able to identify
where the pest is and is not located allows us to achieve enhanced control with
The following case studies show how we have used
mapping, to great benefit, for pest management purposes.
Developing pest population predictions
Mapping allows us to develop pest population predictions based
on other landscape characteristics such as vegetation and soils. One of the
great advantages of entering your data into a Geographic Information System is
that you can take advantage of the tremendous amount of knowledge that is
already known and routinely tracked regarding the earth’s surface. The amount of
detail known about the earth's surface is incredible and continually increasing.
For instance, vegetation type, soil type, slope, streams and wetlands, and
rainfall amounts are mapped in some detail for the entire United States.
Learning the relationship between a pest and the mapped landscape features can
significantly reduce the amount of field work necessary to assess, avoid, or
The following are pest population prediction examples.
Improved risk communication
Mapping allows us to better communicate risk with the general
public. The tick threat map developed for the Boy Scout Jamboree is an example.
By looking at the map, the public can see where they are, where they are going,
and the relative risk of encountering ticks. We believe a map such as this
heightens awareness of the risk and results in more use of personal protective
measures, since the scouts could see that they would in fact be entering a high
risk area for ticks.
Mapping allows us to preserve knowledge so future workers can
take advantage of what is already known about the environment. Pest management
personnel construct their own mental maps through years of surveys. The problem
is that when they move on the new person must then start out with a blank map
and do considerable work to relearn what their predecessor had spent so much
time learning. By having access to mapped observations which illustrate where
pests are most likely to occur, individuals new to an area can save a tremendous
amount of surveillance work.
How the APHC Can Help
We offer several avenues of support to help you get
started and be successful.
- We provide suggestions on hardware and software.
- We provide 1 – 2 day training classes on field referencing data
and setting up your project.
- We provide on site assistance in implementing your GIS and
assist in determining the most efficacious sampling plan and analysis tools for
The APHC GIS Branch is another valuable resource.
- They provide training, troubleshooting, and a help desk for
ESRI’s ArcGIS software products.
- They assist in obtaining imagery and processing it so it is
compatible with your project.
- Contact information for the APHC GIS Branch can be obtained by
calling the toll free number for the Army Public Health
Army Public Health Center Programs