scripting
From autoplot.org
See also developer.scripting, http://autoplot.org/data/jyds, and http://autoplot.org/data/tools/.
More scripts in the SVN repository: [1] (All scripts before and including areaSelect.py have been verified to work with current DOM).
Contents |
1. Introduction
Autoplot may be scripted using Jython. Jython is an implementation of the Python scripting language. A Jython script has easy access to Java libraries.
Scripting can be used for various purposes, including to:
- load data from multiple data sources and combine them to make a new dataset,
- automatically create a series of images, typically one image per file, called a pngwalk,
- plot complex ASCII files,
- modify the default way in which a data file is rendered, and
- create a new application.
Mathematical operations may be applied on Autoplot data objects (QDataSets) using a syntax that is similar to operations on arrays and matricies in IDL or MATLAB. Unlike arrays and matrices in IDL and MATLAB, QDataSets have metadata and physical units; the physical units must be consistent for certain operations to be carried out.
For example, this script
ds1= getDataSet( 'http://autoplot.org/data/image/Capture_00158.jpg?channel=greyscale' ) ds2= getDataSet( 'http://autoplot.org/data/image/Capture_00159.jpg?channel=greyscale' ) result= abs( ds2- ds1 )
loads two grayscale images and assigns the absolute difference to the variable result.
If this script is copied into the script editor (Options->Enable Feature->Script Editor) and executed, the value of result is plotted.
There are three types of scripts:
- #Data Source Context: Used for manipulating data prior to plotting
- #Application Context: Used for modifying the canvas
- #Scripting Context: Used for creating custom applications
2. Script Editor
Autoplot has script editor GUI. Selecting Options->Enable Feature->Script Panel will reveal a tab named "script" where scripts may be entered and executed. The editor provides simple completions for this environment. To see completions, enter TAB or ctrl-space. (Note there is a preference for disabling TAB for completion, since some may wish to use tabs in their scripts.)
3. Data Source Context
3.1. Overview
In this context, scripts load data and return a new dataset (or datasets). Data context scripts have file extension jyds (Jython data dource).
If the above script
ds1= getDataSet( 'http://autoplot.org/data/image/Capture_00158.jpg?channel=greyscale' ) ds2= getDataSet( 'http://autoplot.org/data/image/Capture_00159.jpg?channel=greyscale' ) result= abs( ds2- ds1 )
was saved and uploaded to
http://www.autoplot.org/data/imageDiff.jyds
then
http://www.autoplot.org/data/imageDiff.jyds?result
would refer to this dataset.
Data Source scripts are unaware of the Autoplot GUI and DOM; they can load and operate on data, but they cannot manipulate how the data is plotted (for example, the color of the lines may not be modified in a Data Source script). These scripts can be used outside of Autoplot for this reason, for example in custom applications that use Autoplot's data loading but not the application itself.
Commands available in this context are listed at developer.scripting#Ops. These commands will also appear in a selection menu when TAB is pressed on a blank line in the script panel.
Examples:
- In the repository: [2] .
- In cookbook#Scripting
3.2. Example: Reading ASCII file from URL
Autoplot can plot many ASCII files automatically by using either the help#ASCII_Editor or a URL template. However, many ASCII files have unusual structure and require a script to convert the data in the file into a QDataSet.
Consider this file [3], which has lines of the form
8601012082243337373350403340303 18 22 22 18 48 27 18 27 251.26 0 67.00 8601022082253740303040372720260 22 27 15 15 27 22 12 7 181.05 0 67.60
The file format specification is given at [4]. This script reads the file and convert it into a QDataSet: [5]
3.3. Example: Reading ASCII response URI
Consider a CGI script that returns a simply structured ASCII table
http://linux-pc.jhuapl.edu/cgi-bin/orbitpos.cgi?stime=1353214800&etime=1353387600&ctime=300&mode=gei&header=yes&spacecraft=a
the first few lines of the response are
Year Month Day Hour Minute Second GEIX(km) GEIY(km) GEIZ(km) 2012 07 01 00 00 00 32408.000000 16953.527344 -3749.659424 2012 07 01 00 05 00 32192.494141 17464.601562 -3832.397949
Because the ASCII table is simple, we would like to apply the ASCII template
time=field0&column=field6&timeFormat=$Y+$m+$d+$H+$M+$S
If the URI was to a file
http://linux-pc.jhuapl.edu/orbitpos.txt
we could append an ASCII template to the URI into Autoplot's address bar
http://linux-pc.jhuapl.edu/data.txt?time=field0&column=field6&timeFormat=$Y+$m+$d+$H+$M+$S
and a plot with the correct time axis would be shown.
However, because the CGI script URI has query parameters, we must use a script. Autoplot can load data from remote files, but to load data from services it must have additional code.
To plot this data, use
uri = 'http://linux-pc.jhuapl.edu/cgi-bin/orbitpos.cgi?' params = 'stime=1353214800&etime=1353387600&ctime=300&mode=gei&header=yes&spacecraft=a' template = 'time=field0&column=field6&timeFormat=$Y+$m+$d+$H+$M+$S' file = downloadResourceAsTempFile( URL(uri+params), monitor).toString() import string fp = open( file, "r" ) lineNum = 1 tt= [] dd= [] for line in fp: if ( lineNum>1 ): ss= string.split( line, '\t' ) tt.append( Units.us2000.parse( string.join( ss[0:6], ' ' ) ).doubleValue(Units.us2000) ) dd.append( Units.kiloMeters.parse( ss[6] ).doubleValue(Units.kiloMeters) ) lineNum= lineNum+1 tt= dataset(tt) tt.putProperty( QDataSet.UNITS, Units.us2000 ) dd= dataset(dd) dd.putProperty( QDataSet.UNITS, Units.kiloMeters ) data= link( tt, dd )
3.4. Example: List files in a directory
# All files files= listDirectory( 'ftp://ftp.ngdc.noaa.gov/STP/GEOMAGNETIC_DATA/INDICES/KP_AP/*' ) for file in files: print file # Only files of that match pattern files= listDirectory( 'ftp://ftp.ngdc.noaa.gov/STP/GEOMAGNETIC_DATA/INDICES/KP_AP/[0-9][0-9][0-9][0-9]' ) for file in files: print file
(Note the second example shows a bug where ? cannot be used to indicate a single character. This will be fixed.)
3.5. Example: Query Parameters
Query parameters may be appended to the URI to a Data Source script. The parameter names and values are passed to the script. For example, if you created a script foo.jyds with the following lines at the top
s= getParam( 's', 'deflt', 'label to describe' ) # gets a string parameter, with default value "deflt" f= getParam( 'f', 2.34, 'label to describe' ) # gets a float parameter, with default value 2.34
The user would be able pass options to the script in the URI:
vap+jyds:file:/tmp/foo.jyds?s=abc&f=3.14159
3.6. TimeSeriesBrowse
Scripts can easily support timeSeriesBrowse, so that scripts can be used to create long time series. For example, a script could read any file from vap+cdf:http://cdaweb.gsfc.nasa.gov/istp_public/data/polar/efi/$Y/po_k0_efi_$Y$m$d_v$v.cdf, and then derive data from this (http://autoplot.org/data/tsbDemo4.jyds):
# demonstrate how script can have timeSeriesBrowse to modify another dataset timerange= getParam( 'timerange', '2000-01-09', 'timerange to plot' ) uri= 'vap+cdf:http://cdaweb.gsfc.nasa.gov/istp_public/data/polar/efi/$Y/po_k0_efi_$Y$m$d_v$v.cdf?POTENT&timerange=%s' % timerange ds= getDataSet( uri, monitor ) if ( ds==None ): data= None else: data= abs(ds) data.putProperty( QDataSet.TITLE, 'Positive Spacecraft Potential' )
This would then have URIs that have a default time range of 2000-01-09, but any timerange can be plotted by adding "?timerange=2000-01-08". Scanning on the time axis will cause the script to be called again and more data is loaded.
4. Application Context
4.1. Overview
All scripting commands are available in this context. Application Context scripts modify the GUI, default canvas view, and the DOM. Application context scripts have file extension jy.
Examples:
- In the repository: [6] (All scripts before and including areaSelect.py have been verified to work with current DOM).
- In cookbook#Scripting
4.2. Example: Modify Canvas
Change line color
result= getDataSet( 'http://autoplot.org/data/autoplot.xls?column=A' ) dom.plotElements[0].style.color= Color.RED
4.3. Example: Plot all files in directory
trs= generateTimeRanges( '%Y-%m-%d', '2010-January' ) for tr in trs: dom.timeRange= DatumRangeUtil.parseTimeRange(tr) writeToPng( '/tmp/%s.png' % tr )
runs the application through each day of the month January 2010, making images of each day.
4.4. Example: Progress Monitor
All scripts may use a progress monitor to provide feedback to users. This built-in variable is named monitor .
monitor.setTaskSize(200) # the number of steps (arbitrary units) monitor.started() # the task is started. for i in xrange(200): if ( monitor.isCancelled() ): break # if not called, the cancel button will be insensitive monitor.setProgressMessage('at %d' % i) # this describes actions done to perform the task. monitor.setTaskProgress(i) java.lang.Thread.sleep(100); monitor.finished() # indicate the task is complete
4.5. Example: Create your own tool
Application Context scripts can be added to the Autoplot GUI by putting them in the HOME/autoplot_data/tools/ folder. http://autoplot.org/data/tools/ shows some example scripts.
Under Options->Rendering Options there is a option for showing dates as "YYYY-MM-DD" or "YYYY-DOY". This option could be made available under Tools->Toggle Day-of-Year by placing the following in HOME/autoplot_data/tools/toggleDayOfYear.jy and restarting Autoplot.
# label: Toggle Day-of-Year val= dom.options.isDayOfYear() val= 1-val dom.options.setDayOfYear(val)
5. Scripting Context
Invoked using the --script launch option
Documentation is forthcoming. See examples at ...
