Eyes in the Sky II > GIT Web Course > Module 2 > Week 5 > Getting to Know Querying in GIS > Getting to Know Querying in ArcGIS

Week 5: Monitoring Invasive Species

Getting to Know Querying in ArcGIS

Learn to create and execute GIS database queries to investigate the spread of zebra mussels.

top of page

Launch ArcGIS, Open the Invasive Species Project File, and Add a New Layer

Shortcut1

Movie Icon

Click Add Data to open up the movie in a new window at the SERC media library. Click its name to play it. Close the window when you are done.

loading the player

top of page
Zebra mussels; Dreissenna Polymorpha

Zebra mussels are small shellfish named for the striped color of their shells. They typically attach to objects by threads on their shells. The zebra mussel is native to the Black, Caspian, and Azoz Seas. They were first described in Europe, by Pallas, in 1769.

small zebra mussel image Zebra Mussel

Zebra mussels were first discovered in the Great Lakes of North America in 1988. It is likely that their introduction was due to a ballast exchange from a cargo ship. By 1990 they had spread rapidly to all of the Great Lakes. Soon thereafter they escaped to the Illinois and Hudson Rivers, eventually moving into the Mississippi River system. By 2008, Zebra Mussels had spread across the United States, all the way to California.

Zebra mussels are a significant invader because they can spread both in and out of the water. In their freshwater habitat they can disperse in all life stages. They are prolific biofouling agents and therefore have profound effects on water supply pipes, including nuclear power plant cooling intake pipes. Not only do they damage man made structures, they are disruptive to entire food webs. Zebra mussels primarily consume phytoplankton. Additionally, they consume other suspended materials in the water column. Consequently, areas with dense invasions of zebra mussels have unusually transparent water. In fact, during the invasion of zebra mussels in Saginaw Bay, Michigan the sampling areas experienced a 60-70% reduction in Chlorophyll –a concentrations.

top of page

Adjust the Layers and Zoom in to the Zebra Mussel layer

top of page

Find A Feature By Its Attributes

The Find tool 5211 Find Button is a quick way to locate a feature. However, this type of search works best if you know how to spell, and capitalize, what you are looking for.
top of page

Find the zebra mussels in Ohio.

top of page

Find the US State of Ohio.

Movie Icon

Find Tool Video

loading the player

top of page

Question a Database with Select by Attribute

Another way to find features, especially for larger or more complex searches is to Select by Attribute (This is the same concept as the Database Query in AEJEE).

top of page

Find all the zebra mussels sighted in the year 1988.

top of page

Find all the zebra mussel records from New York, NY.

top of page

Put these two queries together to find all the zebra mussel records in the state of New York in the year 2005.

top of page

Set up a query to find a set of zebra mussels within the date range between 1997 and 2000.

top of page

See how the zebra mussel invasion progressed over time

In the Select by Attributes window, select groups of YEARS with the less than operator. Movie Icon
Query Builder Video
loading the player

top of page

Create and Explore More Database Queries

Practice querying using combinations of set (<, >, =) and Boolean operators (And, Or, Not, etc.)

Try the following:

  1. Use the zebra mussel layer to answer the question:
    Where are the zebra mussels that are in Ashtabula County AND Ohio?
    The equation is: ("COUNTY" = 'Ashtabula') and ("STATE" = 'OH')
    The result of this query is 3.
  2. Substitute OR in the equation above with the zebra mussel layer:
    ("COUNTY" = 'Ashtabula') or ("STATE" = 'OH')
    This query yields 95 records because it gives you BOTH records that are either in the county of Ashtabula or that are in the State of Ohio. The expression "OR" is more inclusive than the operator "AND".
  3. In the US Rivers layer, try this equation that combines both set and Boolean algebra.
    ("SYSTEM" = 'Mississippi') and ("LENGTHCOMP" >= 1361.4323989)
    What question does this query answer?
    What rivers in the Mississippi River system have a length greater than or equal to 1361.4323989?
    Six rivers are selected.
  4. The US States layer has interesting data to practice with.
    What happens when you enter this expression?
    not ("STATENAME" = 'Texas')
    The query shows all the US States other than Texas. The result is listed as 50 States because the District of Columbia is included as a state.
  5. Try this equation with the US States layer:
    ("POPULATION" >= 1211537) and ("MEDIANAGE" <= 35.0)
    What question does this query answer?
    What states have a population greater than 1211537 and a median age less than or equal to 35?
    Twelve states are selected.
  6. The wildcard symbol % combined with the expression LIKE allows you to set up a query that is a bit more open ended. Enter this equation in the Select by Attributes in the US States layer:
    ("STATENAME" like 'A%')
    What result do you get and why?
    This query returns four states: AZ, AL, AR and AK. They are all the States that start with the letter A.
top of page

Build Your Own Database Query and Take a Screenshot

Design and execute a query of interest to you or that you might use in your teaching. Here are a few suggestions.

Once you have built and executed a query, take a screenshot of the map and the Select by Attribute window. In your discussion group, post the question you asked, the equation you used, and the result of your query along with the screenshot. This is the screenshot that is needed for your required weekly activity.

Follow the instructions below to make a screen shot:

top of page

Explore More If You Have Time

top of page

Resources

top of page

Movies on this Page

top of page

How to download movies

top of page

Flash Video Versions

Download these versions to play on your computer. You'll need an appropriate movie player to view the file, such as Flash Player, Real Player (Mac / Win), or Adobe Media Player.

Movie Icon Adding Layers ArcGIS

Movie Icon Find Tool ArcGIS

Movie Icon Query Builder ArcGIS

top of page

iPod Versions

Download these version to play on your iPod or iPhone.

Movie Icon Adding Layers ArcGIS

Movie Icon Find Tool ArcGIS

Movie Icon Query Builder ArcGIS


« Previous Page      Next Page »