| Hi Carol,
I can get the desired result by adding "else 0" to the mask1 and mask2 definitions (which I thought was implied):
let mask1 = if y[gy=sst] lt 20 then 1 else 0 let mask2 = if y[gy=sst] gt 0 then 1 else 0 let mask3 = if (mask1 and mask2) then 1 !funnily enough, no need for "else 0" here
fill/l=1 sst*mask3 !Just Eq to 20N
I can also get it by making the mask in one shot:
let mask = if y[gy=sst] gt 0 and y[gy=sst] lt 20 then 1 else 0
Hope this helps.....but perhaps a ferret expert can clarify when the "else 0" is needed?
Thanks!
Paul
On Feb 3, 2012, at 12:56 PM, Carol Ladd wrote: I am trying to create a lat/lon mask using if statements. I create two overlapping masks and then want to combine them. I would assume I should use “or” to combine the two regions. However, using either “and” or “or” in the masking definition, I get the same result. Is this a bug or am I doing something wrong? I am using Ferret v6.65. See the following script for a quick example: use coads_climatology sh d let mask1=if y[gy=sst] lt 20 then 1 let mask2=if y[gy=sst] gt 0 then 1 let mask3 = if (mask1 and mask2) then 1 let mask4 = if (mask1 or mask2) then 1 fill/l=1 sst*mask1 pause fill/l=1 sst*mask2 pause fill/l=1 sst*mask3 pause fill/l=1 sst*mask4 q Thanks. Carol
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