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Don Murray wrote:
John- 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?