Initial Publication Date: March 13, 2010

Week 5: Monitoring Invasive Species

On This Page

Launch AEJEE, Open the Invasive Species Project File, and Add New Layer
Adjust the layers and Zoom in to the Zebra Mussel Layer
Find a Feature by Its Attributes
Question a Database with the Query Builder
Create and Explore More Database Queries
Build Your Own Database Query and Take a Screenshot
Explore More If You Have Time
Resources
Movies on This Page

Getting to Know Querying in AEJEE

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

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

AEJEE_logo
  • Launch AEJEE by double-clicking its icon on your desktop or by clicking its icon in the dock (Mac) or Launch Bar (Win).
  • Choose File > Open, navigate to ESRI/AEJEE/Data/Invasive_SpeciesAE and select the file inv_spc.axl. Then click Open.
  • Add a new layer to show the sightings of the invasive Zebra Mussels. Click the Add Data add layer button button. Navigate to the invasive_speciesAE folder. Click once on zebra_mussel.shp to select it. Then click OK.
  • zebra_mussel should now be the top layer on your map. Notice that the layer is automatically turned on when it is added.
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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.

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Adjust the Layers and Zoom in to the Zebra Mussel layer

  • Turn on the US States and US Rivers layers.
  • Make US Rivers the active layer buy clicking once on its name in the Table of Contents. Then zoom to the extent of the US Rivers layer by clicking the Zoom to Active Layer Zoom to Full Extent button.
  • Next, make zebra_mussel the active layer by clicking once on its name in the Table of Contents.
  • Click the Zoom to Active Layer Zoom to Full Extent button to zoom to the current extent of the zebra mussel invasion.
    The map shows the extent of the zebra mussel invasion in the United States as of 2008.

    zoomed to mussel
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Find A Feature By Its Attributes

The Find tool 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.

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Find the zebra mussels in Ohio.

  • Make zebra_mussel the active layer by clicking once on its name in the Table of Contents.
  • Right-click on the PC or control-click on the Mac the zebra mussel label in the Table of Contents. Then select Attribute Table. Spend some time looking through the fields and data records that are in the table. Use the scroll bars to move up and down and across the table. Look carefully at the State abbreviations.
  • Close the Attribute Table.
  • Click on the Find find button tool. When the Find window opens, move it so you can see the both map and the window.
  • In the Find window, under Value type in the name of the abbreviation for the State of Ohio, OH. Then select zebra_mussel from the list of Layers to Search. Click Find to search for the features in the layer that have "Ohio" as an attribute.
  • In the results section of the Find window, 98 records have been located. The first result is highlighted. Click Select to show the zebra mussel record in yellow on the map.
  • Click on other records in the list of results and watch the yellow dot move around on the map.
  • To select a group of records, hold the shift key down while clicking on results in the Find window.
  • When you are done, click the Clear All Results button (looks like an eraser) Clear Selections to clear all selections from the map.
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Find the US State of Ohio.

  • In the Find window, select US States in the list of Layers to Search. Click Find to search for the features in the layer that have "Ohio" as an attribute. Click Select to highlight the OH record.

  • Click the Pan To in order to center the map on the State of Ohio.
  • Experiment with using the Find find button tool to locate other States or other information listed in the attribute tables for Zebra Mussels, US Rivers or US States. When you are done, click the Clear All Results button (the eraser) Clear Selections to reset the map.
  • Close the Find window.
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Question a Database with the Query Builder

Another way to find features, especially for larger or more complex searches is to Query the Attribute Table.
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Find all the zebra mussels sighted in the year 1988.

  • Make Zebra_mussel the active layer by clicking once on its name in the Table of Contents.
  • Click the Query Builder... Query builder button tool or select Tools > Query Builder. A new window opens. Move it to where you can see both the Query Builder and the map.
  • In the Query Builder select the field YEAR by clicking once on it. Then click the "equals" sign. Last choose the Value 1988 by clicking once on it. You can also type in this equation (YEAR = 1988) into the box in the middle of the window. Click Execute. Five records are selected on the map.
  • Click Clear to reset the Query Builder.
  • Repeat this process with several other years.
  • Click Clear to clear results from the Query Builder.
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Find all the zebra mussel records from New York, NY.

  • In the Query Builder window, click once on the field STATE, then the "equals" sign, and then click once on the Value NY. You can also type in this equation (STATE = 'NY') into the box in the middle of the window. Click Execute. 427 records have been selected and are highlighted in yellow on the map. Click the image to view a larger version.
    State = NY results3
  • Click Clear to reset the Query Builder.
  • Repeat this process with several other States.
  • Explore the Highlight, Pan, and Zoom buttons at the bottom of the Query Builder window.
  • Click Clear to clear results from the Query Builder.
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Put these two queries together to find all the zebra mussel records in the state of New York in the year 2005.

  • Click once on the field STATE, then the "equals" sign, and then click once on NY. Type the word "and". Click the parenthesis button. Then start the second equation with YEAR equals 2005. Click Execute.
  • You should have 1 record from 2005. How did you do?
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Set up a query to find a set of zebra mussels within the date range between 1997 and 2000.

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See how the zebra mussel invasion progressed over time

In the Query Builder, select groups of YEARS with the less than operator. Movie Icon

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Create and Explore More Database Queries

Practice querying using combinations of set and Boolean operators, such as , =, 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?
  2. Substitute OR in the equation above with the zebra mussel layer:
  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?
  4. The US States layer has interesting data to practice with.
    What happens when you enter this expression?
    not (STATENAME = 'Texas')
  5. Try this equation with the US States layer:
    (POPULATION >= 1211537) and (MEDIANAGE What question does this query answer?
  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 Query Builder In the US States layer:
    (STATENAME like '%A%')
    What result do you get and why?
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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.
  • Try selecting the US Rivers, by Name, Length or System.
  • Select a Lake or River in your State.
  • Select your own State.
  • Select and combine attributes from the US States layer such as population, number of farms, crop acreage or other demographic data.

Once you have built and executed a query, take a screenshot of the map and the Query Builder 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:

  • On a Windows computer, press Alt and Printscreen at the same time. This will save an image of the screen to the computer's clipboard. Launch Paint and choose Edit > Paste.Save the image as a jpeg, giving it a name that describes it, such as River_query.jpg.

  • On a Mac computer, press Command-Shift-4 (Command key = Apple key) all at the same time and drag a box over the area of the screen that you want to capture. This will produce a file named Picture1.png on your desktop. Move Picture1.png to your Week 5 folder or to a place where you can easily find it. Double click on the file to open it in Preview. Rename the image and save it as a jpeg, giving it a name that describes it, such as River_query.jpg.
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Explore More If You Have Time

  • Explore the Attribute Tables of other layers in the map to see the rich assortment of data that can be found in a GIS.
  • Set up database queries that might interest you or your students.
  • Use Add Layer add layer button button to add other data layers that are built into AEJEE and investigate these layers.
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Resources


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Movies on this Page

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How to download movies

  • Click the link to go to the SERC media library listing for the movie. The record will open in a new window.
  • On the SERC media library page, right-click (Win) or control-click (Mac) the link (below the movie on the Flash version pages) to download the movie file to your hard drive.

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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 AEJEE

Movie Icon Find Tool AEJEE

Movie Icon Query Builder AEJEE

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iPod Versions

Download these version to play on your iPod or iPhone.

Movie Icon Adding Layers AEJEE

Movie Icon Find Tool AEJEE

Movie Icon Query Builder AEJEE