Presentation on theme: "Calculating Area in GeoMedia Malcolm Williamson CAST – University of Arkansas, Fayetteville."— Presentation transcript:
Calculating Area in GeoMedia Malcolm Williamson CAST – University of Arkansas, Fayetteville
To calculate the area of polygon features, you’re going to tell GeoMedia to create a new attribute showing the area of each feature. Click on the “Analysis” menu, and then “Functional Attributes”. Start by selecting the polygon feature. In this example we are using “building” under “School Features” as the feature class to which you will add a functional attribute.
Click the “New” button to add a functional attribute. Type in the name “Area” for this particular functional attribute.
To begin defining your function, click on “Most Commonly Used Functions” or “All Functions,” under Categories. If Then, under Functions, double-click on “AREA” to add it to your expression. Finally, under Attributes, double- click on “Input.Geometry1” to tell GeoMedia to calculate area on your building geometries. Type a comma on the keyboard, so that it appears after “Geometry1”. Now go back to the Categories column and click on “Constants”. Scroll down in the middle column and double click on “ProjectedMeas”, and then type another comma. In the same middle column, scroll down just a little further and double-click on “Acre”. Your completed expression should read: AREA(Input.Geometry1,ProjectedMeas,Acre) If you need to, you can type directly in the Expressions window. You’ll know if it’s correct if the word “Double” appears in the Output Type field. Click the “Add” button, then the “Close” button.
Functional attributes produce “queries”. Let’s call this one “building with Area”. Make sure you uncheck the box for “Display functional attributes in map window”, and that you check the box to “Display functional attributes in data window”. Click the “OK” button when you’re done. You will now see the attributes, including calculated area, for each building you’ve mapped.