For the following exercise, first download the AIS Dynamic Data available from OA 7.4. This data is collected by a Naval Academy receiver and is available from “Heterogeneous integrated dataset for maritime intelligence, surveillance, and reconnaissance.” Using the dataset, answer the following questions:

a. How many unique vessels are available in the dataset?

b. List the number of records available for each vessel in the dataset.

c. Find out the spatial (latitude and longitude) and temporal coverage of each vessel in the dataset.

d. Let us use R to understand the relation between speed over the ground and spatial coverage of the vessels that have multiple records.