This analysis uses only scans that are in the working database, i.e. with a quality value of 3 and greater.
I. Scans with no overlap (holes in the sky coverage)

J. Rho has analyzed the scan coverage (last update on Feb. 8, 2001) and concluded that additional scans were requested to fill remaining gaps between scans. Tile re-observations did not fill all gaps. Among the 10 R.A. gaps mentioned in Rho's webpage, 6 are still there. Among the 6 Dec. gaps, 2 remains.
Moreover, 2 new R.A. gaps are found (tiles 307280 and 28605).

We have:

Tile 1	Tile 2	gap type	gap size
307280	189101 and 389101	R.A.	north 16'' south 4''
7960	89007	R.A.	north 9'' south 26''
7962	89008	R.A.	north 25'' south 53''
10849	89015	R.A.	north 2'' south 41''
10877	89017	R.A.	north 2'' south 41''
10819	89027	Dec.	south 1'20''
10833	7987	Dec.	south 1'18''
10817	89013	R.A.	north OK south 18''
10830	89014	R.A.	north 9'' south 35''
28605	28606	R.A.	north OK south 8''

Figures available in postscript here.
 

II. Scans with less than 10, 30 or 50 arcsec overalp
 

	RA ovelap (1)	Dec overlap (2)	Total number
less than 0''	8	2	10
less than10''	9	2	11
less than 30''	34	21	55
less than 50''	600	97	697

(1) columns are:

Tile number

Top distance in arcsec

Bottom distance in arsec

Tile for top distance

Tile for bottom distance

(2) columns are:

Tile number

Est distance in arcsec

Middle distance in arcsec

West distance in arcsec

Tile for est distance

Tile for middle distance

Tile for west distance