CoastWatch Data Analysis Tool Help: Navigation Analysis

In this section:

About navigation analysis

You can open a navigation analysis panel from the Tools|Navigation Analysis menu. The panel provides a way to compare the known coastline geography and the data view image coastline to check for problems with satellite earth location data. Normally this tool would only be used by NOAA researchers working with experimental satellite data. The panel shows a list of navigation points and allows you to add new points to the list, adjust the navigation offset for each point, and save the points to a data file.

Analysis panel controls

The panel holds the following components used to add and modify navigation points:

Add Point
Manual and automatic buttons for adding new points to the point list. Click on one of the buttons, and then click one or more locations on the main CDAT data view to add each point to the list. In automatic mode, the navigation point is run through an automatic navigation algorithm before being added to the list, and the results of the automatic navigation are shown in the Status column.
Navigation Points
The list of navigation points. Clicking on a point shows that point in the view on the right of the panel. You can delete selected points from the list, or clear all the points and start again.
Navigation Offset
The navigation offset for the selected point. The Variable and Box size controls determine what the offset view shows, and also what data is used for automatic navigation. You can adjust the offset in three ways: by clicking and dragging the offset view, by manually adjusting the Row offset and Column offset values, or by clicking the Auto button to perform an automatic navigation. To reset the offsets back to zero, click Reset. Note that the offset view image is independent of the main CDAT data view -- it automatically adjusts the contrast and brightness for the selected navigation point, variable, and box size.

Saving points

Navigation points from the point list can be saved in either XML or CSV format. Click Save... and select a set of points and auxiliary variable data to save with each point. The XML format writes out each point using XML tags and attributes and is useful for web browser display and XML readers. The CSV format writes each point as a line of comma separated values, ready for input to a spreadsheet or plotting program. In either format, the following data is saved for each point:

Back to overview