This function is somewhat analogous to `subset.data.frame()`

.
Subsetting can be by `time`

or `distance`

, but these may not be
combined; use a sequence of calls to subset by both.

```
# S4 method for topo
subset(x, subset, ...)
```

- x
a topo object.

- subset
A condition to be applied to the

`data`

portion of`x`

. See “Details”.- ...
Ignored.

A new topo object.

Other things related to topo data:
`[[,topo-method`

,
`[[<-,topo-method`

,
`as.topo()`

,
`download.topo()`

,
`plot,topo-method`

,
`read.topo()`

,
`summary,topo-method`

,
`topo-class`

,
`topoInterpolate()`

,
`topoWorld`

Other functions that subset oce objects:
`subset,adp-method`

,
`subset,adv-method`

,
`subset,amsr-method`

,
`subset,argo-method`

,
`subset,cm-method`

,
`subset,coastline-method`

,
`subset,ctd-method`

,
`subset,echosounder-method`

,
`subset,lobo-method`

,
`subset,met-method`

,
`subset,oce-method`

,
`subset,odf-method`

,
`subset,rsk-method`

,
`subset,sealevel-method`

,
`subset,section-method`

,
`subset,xbt-method`