Don Murray wrote:
John Caron wrote:
Well, maybe you're right. I notice that CF currently doesnt require
vertical coords. But as a visualizing client, how do you display?
Wouldnt you prefer to insist on something?
No. We import lots of data point data stored in text files that
only has lat/lon coords. In the IDV, we plot the data at the
default Z location defined by the user if we don't have a Z dimension.
We don't always want to assume 0 for the Z value.
Just to be clear: this is not about making assumptions about where the z
value is (sorry i said that earlier), in fact its the opposite: requiring
the data provider to explicitly specify the z position of point data,
in order to be CF compliant.
It seems like the possible options are:
1. z coordinate required, with values convertible to height (eg meters),
with a vertical datum (reference surface like "mean sea level") specified.
2. z coordinate required, with values convertible to height (eg meters).
3. z coordinate required, with values in any vertical coordinate system.
4. z coordinate required, may be a "nominal" value (just a string description)
5. No z coordinate required.
I would lean towards 4, but could be convinced of 5 or 3. We should however
recommend the data provider add as much info as possible, and make sure
there is a standard way to do so.
Could I ask data providers to chime in : how much z info are you willing
and able to put in your files?