Create Difference Maps for NASA Data w/Panoply, Giovanni & Excel

Two fundamental ways to use Earth remote sensing data are to examine anomalies and to monitor change. During this webinar we will show you how to generate difference maps with NASA Giovanni, Panoply and Excel.

Anomalies are visualized by calculating differences between a map for a given time period to a longer-term baseline map. Giovanni’s “quasi-climatology” capability enables anomaly analysis by allowing time-period specification for baseline averaging. This baseline may then be compared to specific time periods to detect differences/anomalies. Change monitoring is performed by simply calculating a difference map for maps from two separate time periods. The difference maps are created by importing the Giovanni NetCDF output files for maps into NASA Panoply, which allows straightforward creation of difference maps and numerous plotting options. Map output values can be translated to CSV in Panoply, then imported into Excel to calculate the difference map array. An Excel macro transforms this array into lat-lon-data value triads. This Webinar will demonstrate the method and provide a variety of examples.

For more information about the NASA Goddard Earth Science Data and Information Services Center (GES DISC), https://disc.sci.gsfc.nasa.gov