using the 'if' function in property manager for calculating an area of certain zones

[Helen123]

Hello everyone, I was hoping someone can help me with this. I need to take out 30 square meters from the calculated area of certain zones and not all of the zones for building permit calculations. These zones are differentiated by the other ones by their zone number, they have a zone number named 30. I have tried writing a custom property in the property manager as follows: IF (Zone number = 30 ; Calculated area - 30 m2). I chose the data type as being a string. It doesn't work. I would like to avoid doing it in excel. Thank you so much!!

Operating system used: Windows 11

[Erwin Edel]

You could setup 30 m² fills flagged as 'substract from zones' on a hidden layer and put these inside the relevant zone boundaries. This will give you: measured area, calculated area and reduced area. All of which you can put in a schedule and use as input for properties.

[Helen123]

Thank you so much Erwin! I suggested this to my collegue but she prefers finding a solution through the property manager. You taught us a nice trick though and I really appreciate it!

[Yves · Accepted solution]

IF ( {Property:Zone/Zone Number} = "30"; {Property:Zone/Calculated Area} - 30 m2; {Property:Zone/Calculated Area} )

 

 

[Helen123]

Thank you so very much Yves! For some reason it wasn't working 😞 I really am grateful for your help.

[Helen123]

Yves I tried it again at home, I don't know what I was doing wrong at the office but it worked. Thank you so much!

[Laszlo Nagy]

Your expression was this:

IF (Zone Number = 30; Calculated Area - 30 m2)

The correct one looks like this:

IF (Zone Number = "30"; Calculated Area - 30 m2; Calculated Area)

The reason yours was not working:

1. The IF function needs three arguments; you only provided two.

2. The 30 was not in quotes, so it was interpreted as a number. So, in the first argument of the IF function, you tried to compare a string (Zone Number) to a number. (It is kind of counterintuitive, but the "Zone Number" field takes a string, not a number.) However, when 30 is put between quotes (like this: "30"), it becomes a string, and the comparison can occur because both values are strings.