1:250,000 Soils of Scotland
(Soils of Scotland 1:250,000 Soils vector)
(qmsoils)

Where/When

Study area

Temporal extent

1947-01-01    to    1981-01-01

Provenance & quality

The 1:250 000 scale soil maps are based on data collected mainly between 1947 and 1981.

Collection methods: The digitising of this dataset was done by Laser-Scan, Cambridge. A film version of the lines was used as a source document for scanning. Dyeline prints of the soil lines were symbolized by hand and used as the source document for coding the polygons. The data was supplied in GIMMS format, and was first used for a joint venture with the Institute of Hydrology, who produced a raster version of the data at a resolution of 100 metres. In the course of this work they discovered and resolved many problems with edge-matching, errors in coding etc, which had not come to light previously. During this work soil boundaries were extended over all the built-up areas on the maps. The vector data was converted to a more useable format in the mid-eighties. Vector strings and arc-polygon labels were read from the GIMMS format, written to textfiles and used to produce plots to assist with the LCF map series. Later the vectors were imported into ARC/Info and a method devised for labelling the polygons. A more rigorous check of the accuracy of the dataset was done, which revealed coding and positional errors. The dataset can be considered as being composed of three layers: soil boundaries, lochs and coastline. These layers vary in their absolute and relative positional accuracy, when compared with the source 1:50,000 documents. Localised errors of up to 200 m have been observed in the lochs layer (possibly due to a mis-registration of plates during the reprographics phase of map production) and also therefore in common boundaries with soil polygons. It was accepted that it would take an inordinate amount of time to correct all the errors and that the best that could be done would be to check and correct the coding of polygons and any gross positional errors of soil boundaries. This work was done using the original data (vector, with built-up areas) and a dataset named Soils of Scotland 1:250,000 Soils and Built-up Area vector was produced. It was from this basic dataset that this dataset the Soils of Scotland 1:250,000 Soils vector was created. Raster versions of both vector datasets were made at resolutions of 100 metres and 1 kilometre.

Other contacts

Custodian

Colin Campbell

The James Hutton Institute

 colin.campbell@hutton.ac.uk