Hi Michael:
It is sort of a bug. If you look at the x,y data variables they stay in meters.
When the georeferencing code (GeoCoordSys) gets called, it needs to convert to
km, because the projection routines use km. The CoordSysTable does that
conversion as a side-effect that really shouldnt be there, i will look at
removing that.
Michael Toews wrote:
Hi John,
I have uploaded a similar, but fresher file to:
http://www.sfu.ca/~mwtoews/annual_oliver_0.2_obs.nc.gz
I have changed my 'proj4string' (from the metadata in my last email) to
'WTK' for Well Known Text, which is used by several open and closed
source GIS packages, including the PROJ.4 library, to describe
projections of gridded spatial elements. The WTK was generated by GDAL
within Python by mocking the properties of a GIS raster. I have only
been creating NC files for the past month, so if there is anything that
is incorrect, please let me know.
WKT I think is a reasonable way to go. Im not much of an expert in it, though,
I think I just followed an examle also generated by GDAL.
We (Rich Signell and others) have been pushing CF to specify Datum etc, so far
without much luck. The best thing to do is for you to post your thoughts and
needs to the CF group, eventually we will probably form a subgroup to bless
some proposal.
You file looks correct.
Thanks.
+mt
John Caron wrote:
Hi Michael: can you make put your file on ftp, so i can have a look?
thanks
Michael Toews wrote:
Hi,
I'm wondering why NetCDFTools 2.2 in the CoordSys tab, the units for
my projected GeoX and GeoY dimensions are displayed as "km" and not
as "m" as I have specified? Shouldn't this be a bug? I realize some
people use km for spatial dimensions, however a vast number of GIS
users use meters for Eastings and Northings. The current CF-1.0
conventions do not specify that the spatial units need to be in "km"
or any particular unit (or at least what I read).
Also, do you know if there are there any plans for CF conventions to
recommend a horizontal datum? I've included the PROJ.4 string in my
file to include this information, since I need meter accuracy. I'm
curious how ESRI will handle the NetCDF format in the pending ArcGIS
9.2 release, specifically if they will make new convention, or
adopt an existing one.
I'm also slightly intrigued at the "regular" fields in NetCDFTools.
I have 1 that was automatically generated for my xdim, which is a
strange looking number. This should be exactly 100.0 m (and so
should the ydim). How is this generated, and why for one var, but no
the other?
Thanks for any help.
+mt
