This example shows how to view cyclone tracking data in a geographic density plot. The data records observations of cyclones over an 11 year period, between 2007-2017.
Load the cyclone track data. The data, produced by the Japan Meteorological Agency, records the location, pressure (in hPa), and wind speed (knots) of cyclones at six-hour intervals. Each row in the table represents the record of an observation of a particular cyclone, identified by a name and an ID number.
To understand the data, plot the tracks of three cyclones, using the
geoplot function. Get the data records for three cyclones, identified by ID number and name. Each observation record provides the latitude and longitude. Plot all the three cyclone tracks on one map by turning
figure latMalakas = cycloneTracks.Latitude(cycloneTracks.ID == 1012); lonMalakas = cycloneTracks.Longitude(cycloneTracks.ID == 1012); geoplot(latMalakas,lonMalakas,'.-') geolimits([0 60],[100 180]) hold on latMegi = cycloneTracks.Latitude(cycloneTracks.ID == 1013); lonMegi = cycloneTracks.Longitude(cycloneTracks.ID == 1013); geoplot(latMegi,lonMegi,'.-') latChaba = cycloneTracks.Latitude(cycloneTracks.ID == 1014); lonChaba = cycloneTracks.Longitude(cycloneTracks.ID == 1014); geoplot(latChaba,lonChaba,'.-')
View the density of all cyclones tracked over this 11-year period using
geodensityplot. In this plot, instead of a seeing the track of a particular cyclone, view all the records at every point for all the cyclones.
geodensityplot calculates a cumulative probability distribution surface using contributions from the individual locations. The surface transparency varies with density.
figure latAll = cycloneTracks.Latitude; lonAll = cycloneTracks.Longitude; geodensityplot(latAll,lonAll)
geodensityplot uses a single color to represent all density values, using transparency to represent density variation. You can also use multiple colors with
geodensityplot to represent areas of varying density. To do this, set the
A density plot can apply weights to individual data points. The weights multiply the contribution of individual points to the density surface.
windspeedAll = cycloneTracks.WindSpeed; geodensityplot(latAll,lonAll,windspeedAll,'FaceColor','interp')
Reference: This cyclone track data was modified for use in this example by MathWorks from the RSMC Best Track Data by the Japan Meteorological Agency (https://www.jma.go.jp/jma/jma-eng/jma-center/rsmc-hp-pub-eg/RSMC_HP.htm).