Use input time in epsg transform?

[lucasw]

With pyproj Transformer I had this:

transformer = Transformer.from_crs(6319, 7912, always_xy=True, allow_ballpark=False)

and then providing the year (with a fractional component in tt_year:

 x, y, z, tt = self.transformer.transform(xx=lon, yy=lat, zz=alt, tt=tt_year)

In rust

let from = "EPSG:6319";
let to = "EPSG:7912";
let proj_convert = proj::Proj::new_known_crs(from, to, None).unwrap();
...
let lon_lat = proj_convert.convert((lon, lat)).unwrap();

I think it's using 'right now' internally as the year time, if I make the python use right now the output seems very close. But can a craft a proj string or do something else to be able to input the time in rust? (matching the allow_ballpark would be desirable as well)

[urschrei]

It looks like the ballpark setting is one of the new supported OPTIONS: https://proj.org/en/stable/development/reference/functions.html#c.proj_create_crs_to_crs_from_pj

I'm less clear on the timestamp – is it part of the CoordinateMetadata discussed in the link above? The 'velocity grids' note makes me doubt that, though. In any case: we should probably support the OPTIONS setting fully, and this looks fairly straightforward, but I'm not sure about the timestamp issue – that's almost certainly a larger piece of work requiring some thought and discussion around design and implementation (would this require a datetime library as a new dependency? What would we use? etc), and we need some more information first: is this related to CoordinateMetadata?