DapperM: A Matlab Interface to Dapper

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DapperM A Matlab Interface to Dapper An
OPeNDAP In Situ Data Service

• D.W. Denbo1, J. Sirott2, W.H. Zhu11UW/JISAO-NOAA/
  PMEL2NOAA/PMEL

IIPS Session 3BAmerican Meteorological
SocietyJanuary 14-18, 2007, San Antonio TX
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Introduction

• The Dapper server provides OPeNDAP protocol
  access to in situ data.
• We have developed an easy to use interface from
  Matlab to Dapper DapperM. DapperM uses Java
  tools that were developed for use with ncBrowse
  and Java Ocean Atlas.

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Design

• DapperM utilizes NdEdit and other existing Java
  tools to provide the user interface for the
  navigation and selection of Dapper Data.
• Design goals include
• Re-use Java components to navigate and select
  data
• Create Java objects that hide the original Java
  data structures.
• Create Matlab scripts that can directly interact
  with the datasets and objects.
• Create an easy to use GUI.

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dpr_gui Example
The Argo dataset is available from Dapper and is
automatically updated regularly from Argo data
assembly centers. In this example, Argo data
from near the Aleutian Islands is selected.
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gtgt dpr_gui
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• Argo data selected from near the Aleutian Islands
  using NdEdit.
• Once Step 4 Select is pressed the selected
  stations are returned to the DapperM object.

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Display after Waterfall Plot button has been
selected.
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• After Save to Matlab has been selected the data
  is available as selection_1 in the users work
  area.
• Matlabs Array Editor is a useful tool to browse
  selection_1 contents.

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• Variables for the first station can be viewed by
  opening selection_11,1.
• The sub-CellArray contains the name of each
  variable and an array holding the data values.

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• Attributes for the first station can be viewed by
  opening selection_11,2.
• The sub-CellArray contains the name and value for
  each attribute.
• The first 9 attributes contain information about
  the entire Dapper dataset.

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Script Example
create waterfall plot collection
dpr_wizard dpr_plot(collection, 1.0) will
prompt for variable get a list of each
stations attributes n1 while
collection.hasNext stn collection.openNext
listn dpr_attributes(stn) n n
1 end
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DapperM Objects

• Attribute - A (name, value) pair.
• DapperM - Coordinates browsing, selecting, and
  downloading Stations from Dapper collections.
• Dimension - Holds the name and length of a
  dimension.
• Station - A container for station Attributes,
  Variables, and Dimensions.
• Variable - A container for variable Attributes,
  Dimensions, and data.

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DapperM Functions

• dpr_attributes - Returns a CellArray that
  contains Attribute names and values of a Station
  or DapperM collection.
• dpr_choose_variable - Selects a variable from the
  DapperM collection.
• dpr_date - Converts Java time (milliseconds since
  1970) to values that will work with Matlabs
  datestr().
• dpr_dimensions - Returns a CellArray that
  contains the dimension names, lengths, and
  unlimited dimension flag.
• dpr_gui - Matlab gui interface to the DapperM
  Java Wizard.
• dpr_plot - Plots a variable of all the Stations
  in the DapperM collection.

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DapperM Functions

• dpr_profiles - Loads a matrix with all the
  variables in the Station.
• dpr_selection - Extracts variables from a Station
  or DapperM collection into a CellArray.
• dpr_station_selection - Extracts variables from a
  Station into a CellArray.
• dpr_variables - Returns a CellArray of variable
  names and a reference to the Java Variable
  object.
• dpr_variable_names - Returns a CellArray with the
  names and units of all station variables.
• dpr_wizard - Opens the Java DapperWizard and
  returns a DapperM collection.

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CellArray Format
dpr_gui returns a profile CellArray with the
format selectionn,1
CellArray, variable data
varm,1 variable name
varm,2 data array
where m is the variable number
selectionn,2 CellArray, station global
attributes
attributej,1 attribute name
attributej,2 attribute value
selectionn,3 longitude (0-360 degrees east)
selectionn,4 latitude
selectionn,5 time (MATLAB format)
selectionn,6 time string
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Summary

• DapperM provides easy access to Dapper in situ
  Server for Matlab users.
• Matlab functions and Java objects can be used
  together for powerful, flexible, application
  design.
• dpr_gui function provides graphical interface to
  select data from Dapper and return a
  multi-dimensional CellArray containing the
  selected data.

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Links

• DapperM Web Page (downloads) http//www.epic.noaa.
  gov/epic/software/DapperM/
• Dapper Server Web Page http//www.epic.noaa.gov/ep
  ic/software/dapper/
• ncBrowse Web Page http//www.epic.noaa.gov/java/nc
  Browse/
• Java Ocean Atlas Web Page http//www.epic.noaa.gov
  /epic/software/JavaJOA.htm
• NdEdit Web Page http//www.epic.noaa.gov/epic/soft
  ware/JavaNdedit.htm