The live map below shows the Merri Creek and its tributaries. Your mission is to use this map to estimate the total length of the streams in the Merri Creek basin.

• Click anyplace on the map to move the cursor to that point.

• Notice the readout at the upper right gives the location of the cursor measured in pixels from the lower left corner of the map.

• You can fine-tune the location of the cursor by clicking on the four arrows at the left, right, top, and bottom of the map. Each click moves the cursor one pixel in the direction indicated by the arrow.

• Use the scale printed at the bottom of the map to determine how to convert distances measured on the map in pixels to distances on the ground measured in kilometers.

• Click the blue button, labeled "Mark point," to record the coordinates of a point. Click it each time that you have moved the cursor to a new point whose coordinates you want to record.

• Click the red button, labeled "List points," to display the coordinates of the points whose coordinates you have recorded. A new window will appear with the information that you have recorded.

• Click the black button, labeled "Clear points," if you want to clear the list of recorded points and start over.

• In the new "List Points" window select the coordinates of the points in the usual way using your mouse and then copy them (command-C in MacOS or CTRL-C in Windows).

• Open your favorite spreadsheet, and use paste (command-V in MacOS or CTRL-V in Windows) to enter the coordinates that you just copied.

• Use this spreadsheet to do the arithmetic needed to determine the total length of the streams in the Merri Creek drainage basin.