DapperM: A Matlab Interface to Dapper — An OPeNDAP In Situ Data Service D.W. Denbo 1, J. Sirott 2, W.H. Zhu 1 1 UW/JISAO-NOAA/PMEL 2 NOAA/PMEL IIPS Session 3B American Meteorological Society January 14-18, 2007, San Antonio TX

16 January rd Conference on IIPS2 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.

16 January rd Conference on IIPS3 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.

16 January rd Conference on IIPS4 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.

>> dpr_gui

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.

Display after “Waterfall Plot” button has been selected.

After “Save to Matlab” has been selected the data is available as “selection_1” in the users work area. Matlab’s Array Editor is a useful tool to browse selection_1 contents.

Variables for the first station can be viewed by opening selection_1{1,1}. The sub-CellArray contains the name of each variable and an array holding the data values.

Attributes for the first station can be viewed by opening selection_1{1,2}. The sub-CellArray contains the name and value for each attribute. The first 9 attributes contain information about the entire Dapper dataset.

16 January rd Conference on IIPS11 Script Example % create waterfall plot collection = dpr_wizard; dpr_plot(collection, 1.0); % will prompt for variable % % get a list of each stations attributes % n=1; while collection.hasNext stn = collection.openNext list{n} = dpr_attributes(stn); n = n + 1; end

16 January rd Conference on IIPS12 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.

16 January rd Conference on IIPS13 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 Matlab’s 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.

16 January rd Conference on IIPS14 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.

16 January rd Conference on IIPS15 CellArray Format dpr_gui returns a profile CellArray with the format: selection{n,1} = CellArray, variable data var{m,1} = variable name var{m,2} = data array where m is the variable number selection{n,2} = CellArray, station global attributes attribute{j,1} = attribute name attribute{j,2} = attribute value selection{n,3} = longitude (0-360 degrees east) selection{n,4} = latitude selection{n,5} = time (MATLAB format) selection{n,6} = time string

16 January rd Conference on IIPS16 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.

16 January rd Conference on IIPS17 Links DapperM Web Page (downloads) Dapper Server Web Page ncBrowse Web Page Java Ocean Atlas Web Page NdEdit Web Page