TEMPORAL COVERAGE OF DOQQS (BW) DIGITAL ORTHOPHOTO QUARTER QUADRANGLES OF CALIFORNIA

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There are 8,457 time intervals associated with items in doqqs (bw) digital orthophoto quarter quadrangles of california as of March 14, 2002. The number of time intervals may differ from the number of items because each item in the collection can have zero, one, or more than one associated time interval. Typically, items have one associated time interval.

The temporal coverage of the time intervals is graphically shown by the histogram below. Each red bar represents a year; each step in the green line, a decade. The height of a red bar or step in the green line reflects the number of time intervals that overlap that time period. Note that the vertical axis is logarithmic.

The following table shows the temporal coverage numerically. The cells in the “Overall” column represent decades; the cells to the right of a decade represent individual years within that decade. The value in a cell is the number of time intervals that overlap the decade or year represented by that cell.

		Overall	Year in decade
			0	1	2	3	4	5	6	7	8	9
Decade	1970s	1	0	0	0	0	0	0	1	0	0	0
	1980s	0	0	0	0	0	0	0	0	0	0	0
	1990s	8456	0	0	13	137	161	719	2473	1819	3133	1