Directions for creating and calculating area of polygons in ArcView

To begin, you must first load the script for calculating area and perimeter into the project's script
list, compile it, and then created a new button in the view bar to run the script.

Adding a Script and a button to run it

1.  Put the disk with the Avenue scripts in drive a:, (or copy the script to a directory).

2.  In the Project window, highlight Scripts, then click on New.  A script window will appear,
along with a row of buttons at the top.

3.  Click the Load Text File button (4th from the right).

4.  In the Load Script window, choose the a: drive (or wherever the file is) and the file
Area_cal.Ave. Click OK.

5.  Compile the script by clicking on the Compile button (10th from right)

6.  Close the script window.

7.  Rename the script something you can remember by highlighting Script1 (or whatever name
ArcView gave to the script you just compiled), then under the Project window, select Rename
Script1.   In the resulting window, type a new name such as Areacalc, then click OK.

8.  Create a new button to run the script by choosing Customize under the Project menu.  In the
Type box choose View; in the Category box choose Buttons.  

9.  Click on the New button, and a new button will appear in the lineup.  In the table below,
double-click on the Click line, and in the resulting drop-down menu window choose the script
Areacalc (or whatever you named it), and click OK.  Add an icon to your button by double-
clicking on the Icon line, and choosing an appropriate icon.

10.  Close the window.  You now have a new script, and a button to run it in your current view.

Creating Polygons, and Calculating their Area

Note: you can create polygons a number of different ways before calculating their area.  Outlined
below is a method of creating polygons using your mouse.

1.  Open the project, bring up the view with aerial photo or other background.

2.  If you are using collected coordinates to outline the boundary of the polygon, display those in
a theme.

3. Under the View menu, select New Theme

4.  Select the Polygon feature type.

5.  In the next window, select the appropriate directory and file name for the theme (for this
course please use the C:\PLGR FILES directory)

6.  Select the Polygon drawing tool icon from the menu bar, highlight it.

7.  Using the mouse, single click on each node that defines the corners of your polygon on the
map display.  Double click on the last one to complete the polygon.  You can create more than
one polygon for this theme at this time.

8.  When polygons are completed, under the Theme menu, select Stop Editing; select Yes to save
when prompted.

9.  With only polygon themes highlighted, click once on the button for calculating area.  

10.  Select the Identity button, then click once on the polygon.  A table will appear showing the
polygon's area and perimeter in the units of the map.  If the map is using UTM coordinates, the
units will be meters; move the decimal four places to the left for hectares; multiply this by 2.47 to
calculate acres.

If the backdrop map is in deg-min-sec, then to calculate area you may need to re-project the view
before you get to step 9:
- Under the View-Properties menu, change the projection to UTMs, then change the distance
units to meters.  Your backdrop map may disappear, but hit the button to calculate area again,
which will update the table using the new units. You can change back to your original projection
once the calculation is complete.