## collect

This command provides a way for station data profiles and time series to be saved in memory as a set. The command format is:

`collect cnum expr`

where `cnum` is the collection number, a value from 0 to 31, and `expr` is any GrADS expression that gives a station data result. If `"free"` is given for `expr`, the collection is emptied and all storage is freed.

### Usage Notes

1. The `collect` command will only work when one dimension is varying, either Z or T. Each time `collect` is issued for a particular collection number, the station data is added to the collection of stations. The order in which stations are added is important.

2. After a group of station profiles or time series have been saved as a collection, use the coll2gr function to convert the collection into a grid.

3. See the section of the User's Guide on Arbitrary Cross Sections for more information.