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PRISM Data and Visualisation
• Data formats and Processing Toolkit
• Low End Visualisation
• High End Visualisation
Prepared by:
• Ros Hatcher
- Met Office
• Karin Meier-Fleischer - MPI-Met
• Gabriella de Martino
- KNMI
Presented by Luis Kornblueh (MPI-Met)
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ESMF. May 2003
File Format & Processing
Library
• NetCDF - File format for data exchange
• CF convention - Metadata standard
• COCO - Processing Library
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ESMF. May 2003
3
ESMF. May 2003
Data Processing
• COCO (CDMS Overloaded for CF Objects)
 Extension to CDMS (Climate Data Management System)
 Written predominately in Python with some C
 Dynamically typed - ease of use for scientists
 Reads & Manipulates netCDF(CF) data
 A single object contains both data and its metadata. The data and
metadata is processed simultaneously.
• Functionalities have been prioritised. Top 10 include: Averaging,
Arithmetic ops., Information, Conversion to new grid, Statistical ops., Extraction
of region and slices, Sampling, Gather, Masking, Tests and confidence intervals.
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ESMF. May 2003
5
ESMF. May 2003
Graphics Package Review
Important criteria for the Low End graphics:
Unstructured/
irregular grids
scripting language
like Python
CDMS/COCO
Integration
DODS and
LAS support
GrADS
No
No
No
Yes
Ferret
Partial
No
No
Yes
CDAT/VCS
Yes
Yes
Yes
Yes
OpenDX
Yes
Proprietary
No
With minor
effort
VTK
Yes
yes
Yes
Yes
netCDF-CF should be opened and read by a
function inside the COCO library, similar to
cdms.open(file name) in CDMS.
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ESMF. May 2003
Software architecture diagram
browser
User Interface
local browser of
the user
Web-based GUI (WP4b)
and/or LAS
server
main Python program
fixed set of functions,
could be changed by the
user
plot graphics to
output file
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ESMF. May 2003
PrepIFS/SMS
defaults
DODS / LAS
data
main
projection
graphics method
linear, mollweide,..
Isoline, isofill, boxfill,...
masking
plot to file
GIF, PS, EPS, ..
sub-regions
........
CDAT/VCS example script:
w=vcs.init()
w.open()
HOPE-E
w.setcolormap('default')
if MESH==1:
ORCA
m=w.createmeshfill('new')
m.mesh=MESH
m.wrap=[0,360]
m.projection=PROJECTION
ls=vcs.mkscale(MIN,MAX,nc=NCOLS)
ls.insert(0,1E20)
ls.append(1E20)
m.levels=ls
m.fillareacolors=vcs.getcolors(ls)
#-- Get new slab.
slab = fdat(VAR, longitude=(LON0,LON1),
latitude=(LAT0,LAT1))
slab = slab.subRegion( squeeze=1 )
print 'set region'
if slab.rank()==3:
slab=slab(slice(0,1),squeeze=1)
elif slab.rank()==4:
slab=slab(slice(0,1),slice(0,1),squeeze=1)
if MESH==1:
# print '**** M.shape = ',M.shape,
'slab.shape = ',slab.shape
for i in range(2):
for j in range(4):
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ESMF. May 2003
.......
Graphical packages review for the High-End
•Features and capabilities of a set of graphical
packages has been examined.
•Some key characteristics are:
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Open Source
Unstructured/
irregular grid
Supporting
community
3D interactive
AVS
No
Yes
Active
Yes
GrADS
Yes
No
Not very active
No
IDL
No
Yes
Active
Yes
NCAR Graphics
Yes
No
Not very active
No
Open DX
Yes
Yes
Very active
Yes
VISAD
Yes
No
Active
Yes
VIS5D+
Yes
No
Active
Yes
VTK
Yes
Yes
Active
Yes
ESMF. May 2003
OpenDX:
from a network to an interactive image
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ESMF. May 2003
VTK: the scripting approach
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ESMF. May 2003