Data Object

The Data Object window represents a data variable, which has been selected for display or analysis. Information about the Data Object such as the source file name, meta data and color palette comes from the Data Source Description and is stored in the file datamanager.txt.

The Data Object has 3 main functions. "Load" controls the loading of data. "Format" allows changes such as subsetting and axis re-ordering to be made. These changes affect the Data Object being altered as well as displays which are connected to the Object. The changes can be done repetitively.  "Save" allows the object to be written out to disk in one of several formats.

Text Entries

Title

This is an optional descriptive name for the object.

Data Source Description

This field shows the name of the Data Source Description associated with the Data Object. Double clicking on the entry will open a Data Source window, which allows the user to change the information described above.

Status

The text area reflects the load status and can have values of "File not found", "Meta Loaded" (meta data have been read-this happens automatically as soon as the Data Object is created), "Loading" (the "Load" button has been pressed and loading is in progress), or "Loaded" (the Data Object is ready to be dragged into other tools). The color bar remains red until a "Meta Loaded" or "Loaded" status has been achieved whereupon it turns green. During the load process, the bar may be partly green.

{SubFiles}

This area, if present, shows sub elements or fields present in a file. Examples include independent and dependent variables. Clicking on an icon allows the adjacent entry to be selected for loading.

Meta Data

Double clicking on icons in this text area will bring up the selected meta data description.

{Projection Axes}

If the user has selected subfiles containing latitude and longitude coordinates as meta data, these subfiles then appear as projection axes.

Buttons

Load

Clicking on the load button  initiates the transfer of data from the source file specified in the Data Source Description.

Save

This button allows the data in the Data Object to be saved to a file.
 

{Add/Add All}

These buttons allow multiple subfiles of the same size to be concatenated.  A subfile selected for concatenation is highlighted in red. Pressing the "Add" button will add this subfile to the concatenation list. All subfiles of the same size as the one in red are shown in yellow. To concatenate all of these subfiles, press the "Add All" button. This will add all possible subfiles to the concatenation list. The "Load" button must be pressed before any changes will be in effect.

{Add as Meta}

Works like the "Add" button but interprets the subfile as meta data. See "Projection Axes".

{Remove/Remove All}

To de-select a subfile, click on it to select it so that is highlighted in red. Then press the "Remove" button. To de-select all subfiles, press the "Remove All" button.

{Selections}

This button/menu will showthe subfiles which have been selected.

{GeoRef}

This is a toggle button that switches geo referencing on/off. Geo referencing is the assignment of latitude and longitude coordinates to data points. This button is only present of there is geo referencing information available in the file. Currently we can read this information automatically from some HDF-EOS files and some HDF files. Geo referenced data cannot be subset. Subsetting must occur before geo referencing.

{Projection}

This button/menu appears only for files which have been created using a geographic projection.  The default configuration uses the projection defined in the file. If the user wishes to display the data on the Globe, the "Rectangular" projection must be selected.

{Remove}

This button, adjacent to the Projection Axes, removes selections highlighted in red.

Format

The Format button allows the user to view details about the file. Pressing the button results in the following type of window:

Information in the second text window, if present, reveals keywords contained in the file header if the file is 'self describing'. Also shown are the "File Type", "Header Size" and "Converters" and other information originally specified using the Data Source Wizard. "Input Order" shows the order in which the data are read in and "Output Order", the order in which they are used. This allows the data to be displayed more easily in some cases. Automatic reordering is the default for VICAR and FITS files. "Dimensions" describes the number of elements in each of the dimensions  in the order shown.

By selecting choices in the "Subset Flags" window, the user can choose to swap data bytes or select a region of the data to subset or subsample. The latter is done by clicking first on 'Subset Active' to turn subsetting/subsampling on.  Use the sliders or type in the text pad to make selections. If this process is carried out prior to loading data for the first time, very large datasets can be sampled in this way. ASCII data files and geo referenced data cannot use this feature at the present time.

Return Button

Selecting this button will return the user to the first data object without making changes.

Apply Button

Select this button to apply changes to the data object and return the user to the first data object.

Applications to Connect to This Application

The Color Tool may be connected to the Data Object via the "drag 'n drop" button.

Applications to Connect This Application to

The Data Object may be connected via the "drag 'n drop" button to Slider, RGB Slider, Combine Slider, 3-Slider, PanZoom, LightTool, 2AxisRotator, 3AxisRotator, Image, Window Tool, Plane,Globe, Histogram, Line Plot, Average, Combine, Compare, Regrid, Profile, FFT, 2-D Scatterplot, Track Pixel, Value View, Calculator, and Contour .

WebWinds Home / Oct 5, 2001