Getting Started with Maps

Getting started with maps

• Note: The Four Elephant Seals CODAP example document shown in the video above can be found here.
• Display a map. Click the map menu item on the toolbar. If a table within CODAP contains mapping data (columns labeled as longitude and latitude), a map of the corresponding points will be displayed automatically.
• If the table does not contain mapping data, a Google API map opens, without CODAP data.
• Toggle between map styles (Oceans, Topo, or Streets) using the buttons in the map's upper right corner.

If latitude and longitude data are included in a data set, CODAP can plot the data points on a map.	Drop an attribute (column header)  from the table on the map to view the data mapped for that attribute.	To view data by frequency, click on the ruler menu on the right of the map, and select “Show grid.”

• View data by frequency. Select the “Show Grid” tool from the ruler menu item to view data on the maps in coarse-grained bins. Use the slider displayed during grid view to adjust the size of the grid cells and discover new patterns.
• Note: Deselect “Points” from the ruler menu item to focus solely on the grid view.
• Drag and drop an attribute from a table onto the map to view mapped data for that attribute.
• To adjust the map's center point drag on the map. Click the dotted square at the map's upper right to enable a selection crosshairs. Use the eye menu to hide or view only the selected cases. 
• To select multiple points on the map click on the dotted square in the upper right corner (the marquee tool) and drag across the points you wish to select. Note that cases selected on map are also selected/highlighted in any tables or graphs you have open. (Also, selecting cases in a table or graph that is open will also select them on the map.) To deselect points on a map, click on any spot on the map that is not a point.

Maps with Boundaries

If a CODAP document contains map boundary data, CODAP will display the information on a map. For example, the graph on the right contains information about the Total Population in the United States.

• Display maps with geographic boundaries. CODAP can also create maps with geographic boundaries if the boundary information is included in a data set, like in the map above. To do so, drag a boundary attribute onto the map. To add boundary information to a dataset, add a new attribute to the table by clicking the plus sign in the upper right corner. Give the new attribute a new name if you like, such as "Boundary" (click on the name of the new attribute and select "Rename"). Then, click on the name of the new attribute in the table and select "Edit Formula." Next, type in a formula to look up the boundary based on another attribute in the dataset. Typically this is an attribute specifying the name of the geographic areas. For example, the formula used to create state boundaries in the example shown above is: lookupBoundary(US_state_boundaries, state) ("state" is an attribute specifying the state names in this dataset, while "US_state_boundaries" is a set of boundaries where CODAP looks for the boundaries for the states listed under the "state" attribute). Once the boundary variable is added to the dataset, the boundaries will appear on the map. You may color the boundaries by the values of an attribute in the dataset by dragging that attribute and dropping it on the map. More information on how to enter a formula for an attribute can be found here and more information on the boundary lookup formulas can be found here. Additional information on how to set up map boundaries can be found here and in the video below.
• To select multiple areas of a graph with boundaries, hold down the Shift key and click on each boundary area you wish to select. Note that these areas will also be selected in any graphs/tables you have open (selecting the areas in a table or graph will also highlight them on the map). To deselect the areas, click on any part of the map that does not have boundaries.

An example CODAP document with a map with boundaries can be found here.

The following video shows how to create map boundaries in CODAP that are not included in the standard boundary set in CODAP:

More detailed information on maps in CODAP can be found in the chapter on maps in Awash in Data by Tim Erickson.