CoastWatch Data Analysis Tool Help: Data Surveys

In this section:

What are surveys?

Surveys allow you to compute statistics on areas of the data view. Performing a data survey results in a printout of statistics, a plot of the survey data, and an outline of the survey area on the data view. Surveys can be performed at a point, along a line, or within a rectangle or polygon.

Survey modes

The following figure shows the current list of surveys, and the survey results and plot tabs:

You can perform a survey on the data using the CDAT toolbar buttons as follows:

Point
A single point is surveyed, with no statistics or plot. A point survey is a good way to mark a certain position and easily be able to recall its data value, such as for an ocean buoy.
Line
A straight line is surveyed, with statistics and a plot of the data values along the line. A line survey simulates an airplane or ship track of the data values, and is useful for gradient and front analysis.
Rectangle
A rectangular box is surveyed, with statistics and a plot of the histogram bins within the box. A box survey is useful for a clustering analysis to show groups of similar data values in an area as peaks in the histogram.
Polygon
A polygon is surveyed, with statistics and a plot of the histogram bins within the polygon. Polygon surveys are similar to box surveys, but can help when the area has an irregular shape.

Survey list

Once added to the survey list, surveys are similar to overlays, in that they can be modified, renamed, set visible or invisible, moved up or down in the list, and removed — see the overlays section for details. Select a survey in the list to recall its specific data in the Results and Plot tabs.

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