## set x|y|z|t

`set x|y|z|t val1 <val2>`

This sets one dimension of the dimension environment using grid coordinates. You may use whatever coordinates are convenient to you. Issuing `set lon` is equivalent to issuing `set x`, both set the `x` dimension. The difference is only the units you wish to enter the command in.

When you enter just one value, that dimension is said to be "fixed". When you enter two values, that dimension is said to be "varying". The combination of fixed and varying dimensions defines the dimension environment.

### Usage Notes

An important note: When you enter dimensions in grid coordinates, they are always converted to world coordinates. This conversion requires some knowledge of what scaling is in use for grid to world conversions. The scaling that is used in all cases (except one) is the scaling of the DEFAULT FILE. The exception is when you supply a dimension expression within a variable specification, which will be covered later.

### Examples

`set t 1` (sets time to the first time in the data set -- using grid coordinates in this case. Time is now a fixed dimension).