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# field calculator

5257
23
06-15-2015 02:16 PM
Deactivated User

I am using ArcGIS 10.3 basic desktop to interpolate GPS soil points and then create a lime prescription map. I can easily interpolate the points however when I use the field calculator to enter the target lime formula for the desired pHw level I get an error message of 99999 that says a field name was not found or there were unbalanced quotation marks. The formula was produced by a leading university and has been used in numerous types of software so I don't believe it is the problem.

Thanks

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23 Replies
by
Regular Contributor II

What does the formula look like?

Are you using python parser of VB parser?

Jeff Ward
Summit County, Utah
Deactivated User

VB parser. I am not familiar with python code.

MVP Honored Contributor

^ the image doesn't seem to work. Just copy/paste the expression into your post.

Deactivated User

phw[0,6.24] : ((6.5-(-0.6))2*1.5)

phw[6.24,max] : 0

This is for a ph target of 6.3

MVP Honored Contributor

This doesn't appear to be either VB Script or Python, your only two options in the field calculator. As I'm not familiar with your subject matter whatsoever, can you please explain, in words, what that formula is supposed to do?

Deactivated User

No this is a soil equation not python or VB, This is a formula that is intended to raise the ph level of soil matter by applying lime. The formula is applied to areas of low ph with the intent of increasing the ph level to 6.3. Hope this helps.

MVP Honored Contributor

No, this still isn't in language I, or the field calculator, will understand. The field calculator works like: for each row in the attribute table, take some value(s) in another column(s), manipulate it somehow, and return some new value into the calculated column for that row.

Is "phw" the name of the column we are getting values from or calculating to? What does your notation phw[0,6.24] mean - something like if phw is between 0 and 6.24, apply this part of the formula?

Deactivated User

Yes the phw field contains the ph values that we getting the values from. The formula only applies lime to areas that have ph levels of below 6.3.

by
Deactivated User

S, you have a feature class of points, and you're trying to calculate the value of a field based on the phw field, is that correct?