1:25,000 Soils of Scotland
(25K soils)
(Soils25K_v8d_Phase_3)

The 1:25 000 scale soil maps are based on data collected mainly between 1947 and 1987.

Collection methods: A source document was chosen. The order of preference was dyeline master, clean copy, compilation then working draft. The document was overlayed with a piece of matte plastic on which the details of the source were recorded, registration marks were drawn and three tablet reference points were indicated. An overlap on 1-2mm was drawn if there was no suitable line on the base map. The map was then compared with its neighbours and the detail drawn into the overlap area which avoided underlap problems later. A check was made of the coding across sheets. Problems with line placement or coding were noted on a query sheet. The soil lines were digitised following the centre of the line and continuing into the overlap area. Stream digitising was not used. Nodes were snapped where two or more lines met at a point. The line file was cloned to make the point file, to ensure that the geo-referencing was the same in both files and the lines were then deleted from the point file. Rubbersheeting points were digitised at every grid intersection on the base map, ie every 1km intersection. Rubbersheeting points were given the code of 1. Soil codes are shown on the 1:63,360 map as letters indicating soil association and soil series. These letter codes were translated back to the five digit numbers used in the Oracle table Soils of Scotland Soil Series Codes (4100001001). A single point was digitised within each polygon and the appropriate five digit code assigned to it. A plot was made, checked against the original and any discrepancies noted. Queries were noted on the query sheet and passed with the map to a soil surveyor to be resolved. Once all the edits had been completed a final plot was made and passed to another member of the digitising team, for a final check. Files were made which would be acceptable to ARC/Info. Coverages were generated, rubbersheeted, and the rubbersheeting points removed. Clipped with LCS88 coastline and lochs and finally edgematched to its neighbours.

This release includes previously unreleased data in the north and south-west of Scotland. I also includes modifications to Strichen and Arkaig Associations as follows: prior to the completion of the 1:250 000 scale national soil map, soils developed from schists were allocated to the Strichen Association, however, during the national scale mapping, this Association was divided into two based on the stratigraphic age of the Schist (Moine or Dalradian) giving rise to the Arkaig Association (Moine Schists). The extent of these two Associations followed the geological mapping and some soils previously allocated to the Strichen Association were reclassified as belonging to the Arkaig Association. Subsequent revisions of the geological map have relocated the boundary between the Moine and Dalradian Schist such that the soils reallocated to the Arkaig Association are in areas now mapped as Dalradian Schists by geologists. During the revisions of the 1:25 000 and 1:63 360 scale soil maps, it was decided to revert to the soil Association to which the soils in this area were allocated originally, thus the areas allocated to either the Strichen or Arkaig associations on the more detailed maps will differ from the national scale map.

This data set is undergoing a phased revision. This version of the data is Phase Three and was released on 4th March 2015. This data set includes all the data previously issued, however the data with an attribute value of "3" in the attribute ReleasePh has been revised in this release. Revisions to the remaining parts of the data set will follow in a subsequent phase.