请问GrADS可以对nc数据中的温度进行设置吗？

yangchao888

river 发表于 2017-4-11 21:42
使用判断语句来辨别数据的大小啊，if  ····  endif

老哥，可以说的更明白一些吗

river

yangchao888 发表于 2017-4-21 20:37
老哥，可以说的更明白一些吗

你不会编程的吗，fortran一个道理
if(r>=50)
if(-14<=t<=0)
'define a=(r-50)*2*(t-273)*(t-273+14)/(-49)'
endif
endif

wdd1992

遇到同样的问题，请问楼主解决了吗

wdd1992

river 发表于 2017-4-23 09:08
你不会编程的吗，和fortran一个道理
if(r>=50)
if(-14

试了下if语句不能提取满足条件的格点啊

river

wdd1992 发表于 2019-6-16 15:37
试了下if语句不能提取满足条件的格点啊

不好意思，这个很久了，我也快忘记了。不过确实是我的问题，在GrADS里面的 if 语句可以用来提取满足某些条件的数据，但我回复的用法有问题。你可以去看看官网的函数说明。http://cola.gmu.edu/grads/gadoc/gadocindex.html
if()
This function performs an if/then/else expression evaluation. It is available starting with GrADS version 2.1.1.b0.

Syntax
if (logical_expr, then_expr, else_expr)

where:

logical_expr   - any valid logical expression that has a boolean (yes/no) result
then_expr      - the result expression if logical_expr is true
else_expr      - the result expression if logical_expr is false
All the arguments must be expressions for gridded data -- the logical operators and the if() function have not yet been implemented for station data.
Usage Notes
The logical_expr should include one or more of the logical operators: =, !=, >, >=, <, <=, |, &

The result of a logical operation is boolean -- an answer to a yes/no question. If the expression is true the result is 1, and if the expression is false the answer is -1. The if() function will evaluate logical_expr and wherever the result is >0 it will place the value of then_expr, and wherever the result is <0 it will place the value of else_expr.

The argumentsthen_expr and else_expr may be any GrADS expression, including a constant. If you want then_expr or else_expr to be undefined, then use maskout() instead of the if() function.
Examples
Here is a script sample to find the minimum and maximum 2-meter temperature at each grid point over a 12-month period:

'define tmin = const(t2m,1e9)'
'define tmax = const(t2m,-1e9)'
t = 1
while (t <= 12)
  'set t 't
  'define tmin = if(t2m<tmin,t2m,tmin)'
  'define tmax = if(t2m>tmax,t2m,tmax)'
  t = t + 1
endwhile

river

在wdd1992的提醒下，特来给楼主yangchao888道歉，我之前的回复有问题，而且语气也不好，估计是当时遇到烦心事儿了。在此诚恳道歉，对不起！真的不好意思，希望没有误导你。