Transcript ppt - ViRBO

Autoplot Overview

Autoplot developed originally for ViRBO Virtual
Observatory, then adopted by VMO, and RBSP
instrument and other teams
Autoplot Overview


Autoplot developed originally for ViRBO Virtual
Observatory, then adopted by VMO, and RBSP
instrument and other teams
Uses existing data resources.
(As opposed to first
downloading the data)

Autoplot URIs
identify data locations.
One URI=one plot
Autoplot Overview
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Basic idea is it plots the data in a text file or
where ever.
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decides render type (e.g. spectrogram or
lineplot)
autoranging
few screenshots and demo
I’ll talk about:
• Autoplot’s internal data model, (way of
representing the numbers), “QDataSet”
• Autoplot URIs which identify data
• Using Autoplot to get data into Matlab and IDL
• Autoplot’s open source components
Autoplot’s QDataSet Data Model
Data model “QDataSet” is in the middle of this.
All data is represented in this model.
Why not NetCDF / the Common Data Model?
Mostly I hadn’t come across it. But it’s very lightweight
and I think it would serve other data systems nicely.
QDataSet had been developed for PaPCo, an IDL code.
“Ported” to Java and matured in Autoplot.
Small Java interface with many implementations.
wrap NetCDF
double arrays
java.nio.Buffer
etc.
QDataSet at the center
QDataSet is at the middle of this, so it’s really:
PLUGIN -> "QDataSet" -> DATA CONSUMER
Where plugin is:
text files, but also CDF, netCDF, HDF5, OpenDAP, xls,
and jpg, Fits, CEF, ... and … (~20 plugins total)
And data consumer is:
Plot graphics, but also: Matlab, IDL, Reformatting,
Data Mining, ???
And fairly extensive set of operators on QDataSet exists
already.
Autoplot
figure-5-new.PNGESSI Conference 2010
Autoplot URIs
Autoplot defines URIs for locating data, for
example:
vap+dat:http://autoplot.org/data/somedata.dat
Autoplot resolves URIs into plottable datasets by
identifying the plugin to handle the URI, which
resolves the URI into a dataset.
vap+cdf:http://autoplot.org/data/somedata.cdf?BGSM
Autoplot URIs are intended to be stored in bookmarks
lists, sent in emails, and stored in SPASE records.
Autoplot data into Matlab
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Matlab and IDL have ad-hoc APIs for accessing
various forms of data.
Anything you can plot in Autoplot, you can read into
IDL and Matlab using the Autoplot URIs.
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Matlab interface is very easy.
IDL you must use Java connector (but once that’s
set up it’s easy)
Matlab Example Script
% Download ~20 MB jar file
javaaddpath('http://autoplot.org/images/AutoplotAll.jar');
apds = org.virbo.idlsupport.APDataSet;
apds.setDataSetURL( ‘http://autoplot.org/data/somedata.dat' )
apds.doGetDataSet;
y= apds.values;
x= apds.values('dep0');
plot( x, y )
Note: CDF files require a C binary and do not work in this mode. (But
Nand’s pure-java CDF reader will be incorporated.)
Software Reuse
Uses open source components
• Things I nothing about: e.g. iText for PDFs,
HSSF for spreadsheets, JPEG metadata
• Things for that I know just a little about:
• NetCDF, CDF, OpenDAP for reading data
• Things I know lots about:
• das2 graphics library (Plasma Wave Group, UIowa)
• QDataSet
Software Reuse: use cases
Autoplot itself is open source and is being
incorporated into many projects
• Graphics for RBSP mission
• QDataSet incorporated into das2.
• experimental use on ISTP/CDF web server and
Ace Science Center.
• Jon Vandegriff hacking out pieces for their
RBSP applications at APL.
Software Reuse: das2
Autoplot/das2 show how Autoplot provides an application
the RPWS group always wanted.
Autoplot has matured das2 software. Fixed obvious
bugs. Very easy to see Plasma Wave Group elements
(e.g. simple data model, and its data server) and forces
library to become cleaner.
Autoplot has “pushed” das2 to do new things. (e.g. zoom
pan, Google maps-like navigation)
Last, provided better technologies into das2, like its
QDataSet data model will become heart of das2.
Software Reuse
• Apache Math library downloaded and in use within
minutes