Question: What are the purposes of SO15 's coverage district ?

text: SO postcode area
Coverage
The approximate coverage of the postcode districts :
The SO postcode area, also known as the Southampton postcode area, is a group of 23 postcode districts in England, which are subdivisions of nine post towns. These postcode districts cover south and central Hampshire, including the post towns of Southampton, Winchester, Alresford, Brockenhurst, Eastleigh, Lymington, Lyndhurst, Romsey and Stockbridge; and other towns, such as Totton, Hythe, Hedge End and Bishop's Waltham. The area originally had both single and double-digit postcode districts. From a short time after inception of postcodes in Southampton, 'large users' within the old SO1 and SO2 postcode areas (which broadly covered the area of the City) were allocated SO9 postcodes. In the early 1990s, a shortage of available postcodes occurred due to increased demand. On 1 December 1993 Royal Mail took the step of dividing all single-digit SO districts so that new, smaller SO districts could be drawn with two digits rather than one. For example, the SO1 and SO2 districts were divided into SO14-19. The Southampton postcode area is now, therefore, one of the few in the United Kingdom with no district numbered '1'.
Postcode district Post town Coverage Local authority area
SO14 SOUTHAMPTON City Centre , St. Mary 's , Newtown , Nicholstown , Ocean Village , Chapel , Eastern Docks , Bevois Valley Southampton
SO15 SOUTHAMPTON Shirley , Freemantle , Banister Park , Polygon , Millbrook , Redbridge Southampton
SO16 SOUTHAMPTON Bassett , Lordswood , Lordshill , Redbridge , Rownhams , Nursling , Chilworth Southampton , Test Valley
SO17 SOUTHAMPTON Highfield , Portswood , St Denys , Swaythling Southampton
SO18 SOUTHAMPTON Bitterne , Bitterne Park , Harefield , Townhill Park , Chartwell Green , Mansbridge , Southampton Airport Southampton , Eastleigh
SO19 SOUTHAMPTON Sholing , Thornhill , Woolston , Weston Southampton
SO20 STOCKBRIDGE Stockbridge , King 's Somborne , Middle Wallop Test Valley
SO21 WINCHESTER Compton , Colden Common , Easton , Hursley , Itchen Abbas , Martyr Worthy , Micheldever , Owslebury , Shawford , South Wonston , Sutton Scotney , Sparsholt , Twyford Winchester
SO22 WINCHESTER Badger Farm , Fulflood , Hursley , Littleton and Harestock , Olivers Battery , Pitt , St Cross ( W ) , Stanmore , Weeke Winchester
SO23 WINCHESTER City Centre , Abbotts Barton , Bar End , Highcliffe , Hyde , St Cross ( E ) , Winnall Winchester
SO24 ALRESFORD New Alresford , Old Alresford , Cheriton , Tichborne , Ropley Winchester
SO25 WINCHESTER Bulk users non-geographic
SO30 SOUTHAMPTON Botley , Hedge End , West End Eastleigh
SO31 SOUTHAMPTON Warsash , Hamble-le-Rice , Locks Heath Netley Abbey Eastleigh , Fareham
SO32 SOUTHAMPTON Bishops Waltham , Corhampton , Droxford , Durley , Exton , Meonstoke , Shedfield , Soberton , Swanmore , Upham , Warnford , Wickham Eastleigh , Winchester
SO40 LYNDHURST , SOUTHAMPTON Totton , Lyndhurst , Cadnam , Marchwood New Forest
SO41 LYMINGTON Lymington , Milford-on-Sea , Pennington , Boldre , Hordle , Sway New Forest
SO42 BROCKENHURST Beaulieu , Brockenhurst , East Boldre New Forest
SO43 LYNDHURST Lyndhurst , Minstead , Bramshaw New Forest
SO45 SOUTHAMPTON Hythe , Fawley , Blackfield , Calshot , Hardley New Forest