Data Source Object









The Data Source object allows the user to change a Data Source Description, and/or a Data Directory that was originally created using the Source Wizard or by editing the datamanager.txt file.

Text Entries and Related Buttons

Menu

This button allows the choices "Edit on/off" which turns on/off the ability to change fields, "Apply" which saves the changes in a temporary location ("save" must be selected when exiting for permanent changes), "Open..." creates a new Data Object, and "New Meta Data" creates a new meta data description.

Title

This is an optional descriptive name for the source. See "tricks" below.

Source File

The name of the local file or URL must be entered here. A file may be compressed (with gzip) however such files (.gz) load very slowly on the Mac

Path

The path where the Source File may be found. This information may also be placed in the file "paths.txt". The "Find File" button will launch the File Finder, which will fill in this field.

Find File

This button brings up the File Finder if the user wishes to search for a file.

File Type

Files can be 'self-describing', i.e. they can contain meta data (data about data) as well as data. Current file 'self-describing' formats are: Flexible Image Transport System ("FITS"), Planetary Data System ("PDS"), Video Image Communication and Retrieval ("VICAR"), Microsoft's bitmaped (BMP) format, Network Common Data Format ("NetCDF") and Hierarchical Data Format ("HDF") which includes  HDF-EOS  ("HDFEos"), Tagged Image File Format ("TIFF"), Microsoft's bitmaped ("BMP") format and  Geocoded raster imagery using TIFF ("GEOTIFF"). In addition, the following choices are available which are not 'self-describing': floating point numbers ("RawFloat"), byte data ("RawByte"), integer data ("RawShort"), tabular ASCII data ("Table") and ASCII data ("Ascii"). Use the "New" button to change the File Type.

Conversion

Currently limited to "linear", "Log" (natural log) or "Log10" (log base 10). Use the "converters" button to select or type. The options are defined in datamanager.txt.  Use the "New" button to change the conversion type.

Interpolator

When irregularly spaced data (e.g. geo-referenced, Table or HDF-EOS Point data) are displayed on a regular grid, intermediate grid points can be filled in using either a nearest neighbor ("NearNeighbor") or bilinear interpolation ("Bilinear"). If "None" is selected, there is no interpolation.

Data Directory

This field indicates the directory location where the data source is to be saved. The "Temp" directory is the default, however all sources in the temp directory disappear upon exit. Use the " New " button to select a directory from your datamanager.txt file.

Color

Selecting this button will bring up a Color Tool. Palette choices can be described in the file colors.txt. Default values included in the colors.txt file are "grey", "rgb", "rgbI", "temperature", "oxygen", "cutten", "bands" and "combine" and may be selected using the "colors" button or you may type in a name. For additional information, see Color Tool.

Some of the following fields are present for non 'self-describing' files:

Schema

Schema must be specified for ASCII or Table data.

Header Bytes (Skip)

This optional field specifies the number of bytes to skip at the beginning of all non-'self-describing' files, except Table.

Input Order

The input order specifies that the most rapidly varying dimension will be displayed in the "1" or horizontal direction, the next rapidly varying dimension will be displayed in the "2" or vertical direction and the last dimension will be displayed in 'slices'. The ordering for a given dimension can be reversed by putting a "-" character in front of a number. Thus, instead of the default "123" one were to enter "3-21", WebWinds would assume that the fastest varying dimension is 3, that the 2 variation should be displayed in reversed order and the slowest varying dimension is 1.

Dimensions

Each of the dimensions must be given a size for all non-'self-describing' files, except Table. Fields are separated with spaces

Column Names

This appears only for Table  data. If you wish to provide names for columns they can be added in this field, one to a line. There are two ways to specify the column names. If you wish to specify all column names then simply type them in order. If you wish  to specify only the column names that correspond to the selected columns in the schema then supply only those names but make sure that the first name corresponds to the first column specified in the schema, the second to the second,... etc. If the data object cannot tell how you want them specified ( i.e. more column names than are in the schema but fewer than are actually on the file ) then WebWinds will assume that the names are for the first columns and then will default the remaining columns. If you do not wish to supply column names at all then WebWinds will use default names. You can specify column names in datamanager.txt, but you must use the first method, i.e. all column names must be specified. E.G.

columns 7 "cntr" "RA" "DECL" "f12" "f25" "f60" "f100"


Meta Data

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

Applications to Link to This Application

None.

Applications to Link This Application to

None. Pressing open will cause this window to 'morph' to a Data Object.

Tricks and Gotchas

If you wish to open the same file twice with different parameters, e.g. if the "Type" is different, you must use a unique title.

WebWinds Home / Oct 5, 2001