Cairngorms layer colour explorer

This application allows six different Bartholomew half-inch to the mile maps to be viewed and compared. The Bartholomew half-inch maps we have included date between 1890 and 1905, and all cover the same area of the Cairngorms. Between each edition over fifteen years, Bartholomew used a different palette of colours to represent the height of the ground. This application shows the evolution of this 'contour layer colouring' technique for this area. The maps are georeferenced so that they can easily be compared to each other and to modern maps and satellite images.

Bartholomew's half-inch series

To begin with, Bartholomew printed their half-inch maps in Scotland as stand-alone sheets known as 'District Sheets' and by 1886 the whole of Scotland was covered. They then revised the maps into an ordered set of 29 sheets covering Scotland in a regular format. This was first pubilshed under the title Bartholomew’s Reduced Ordnance Survey of Scotland. The half-inch maps formed the principal content for Bartholomew's Survey Atlas of Scotland published in 1895. Bartholomew then moved south of the Border to the more lucrative but competitive market in England and Wales, whilst continuing to revise the Scottish sheets. The first complete coverage of Great Britain at the half-inch scale was achieved by 1903.

Bartholomew revised the most popular half-inch sheets every couple of years, ensuring that their maps were more up to date than their main rival, Ordnance Survey. Popular sheets had print runs of several tens of thousands per edition, involving nearly 20 different layer colour plates for hillier areas with more colour.

Layer colouring

The half-inch maps were distinctive for using different layers of colour to represent landscape relief. A subtle and innovative gradation of colour bands were employed for land at different heights. Lighter greens were used for low ground closest to sea-level, darker greens and browns for higher ground, with white used for mountain tops. The map printed on 24 December 1902 is particularly remarkable for its use of pink tinting.

Whilst layer colouring had been developed in Germany from the 1860s, Bartholomew's development of it was both innovative and influential. John Bartholomew junior (1831-1893) first used the firm's trademark layer colouring in Baddeley’s Thorough Guide to the English Lake District (1880). His son, John George Bartholomew (1860-1920), later went on to refine the style.

Sources of information

Bartholomew based their half-inch maps on more detailed Ordnance Survey mapping at the one-inch to the mile (1:63,360) scale. Bartholomew had published 'Reduced Ordnance Maps' of Scotland, England and Wales at this scale from the 1890s. These maps were progressively revised and updated with new information.

Bartholomew deliberately selected only certain details from the Ordnance Survey maps, and also added their own. They added categories of roads, including drove roads, steamer routes, and rights of way that were not shown on Ordnance Survey maps. Their rendering of Gaelic place names was often more sensitive and accurate than Ordnance Survey's. Bartholomew took information from a range of sources including local authority surveyors, and from a large and growing body of customers who they invited to write in with corrections. The aim was never accuracy in all respects, just ‘sufficient accuracy for the purpose required’.