Mapping Scotland’s Synods, 1560-1689

As we step up our preparations for Stage 3 — venturing out from Lothian and Tweeddale and into the rest of Scotland — we are busy scoping out the extent of the work before us (spoiler: there is a lot). We have already entered Presbytery data to Wikidata. Now we turn our attentions to Scotland’s provincial synods.

Arrowsmith’s ecclesiastical map of Scotland (1825)

Many of our readers will know about Aaron Arrowsmith’s 1825 ecclesiastical map of Scotland. A scanned version is available on the National Library of Scotland website here. I’ve spent a lot of time looking at this map, but there are two problems with it, at least from our perspective: it shows the shape of the nineteenth-century Kirk of Scotland and, unlike so many of the terrific maps on the NLS website, it is not georeferenced.

Fortunately, NLS have adopted the International Image Interoperability Framework (IIIF) on all of its scanned map images. This means that the image can be exported to various different software viewers (ARCGIS, CanvasPanel, Mirador, Recogito, etc). Using the free website, we imported Arrowsmith’s map and started the georeferencing process. tied Arrowsmith’s map to modern map data

By using, we were able to overlay Arrowsmith’s representation onto a modern map, pinpoint known places and features, and allow the website to adjust the nineteenth-century map to accord with modern-day cartography.

Georeferencer has an extra trick up its sleeve: the georeferenced map can be taken directly to MapTiler, a service that allows users to create vector shapes on top of georeferenced maps. Translation: we could now trace the boundaries of provincial synods shown on Arrowsmith’s map and use them in modern projects.

Tracking the Aberdeenshire coast on MapTiler

This is fiddly work: you start with a pretty generalised polygon and have to edit it, by hand, to accord with coastal features and the like. There is the added complication that Arrowsmith’s knowledge of certain parts of Scotland was less-than-stellar: thankfully, MapTiler allows users to alter the opacity of each layer so one can see how the modern and historical maps compare. Of course, there are editorial judgements to be made here, especially in areas where Arrowsmith’s map lacked key detail.

We’re using Arrowsmith’s nineteenth-century map here and our project covers the period 1560 to 1689. Unsurprisingly, a number of features had changed between the end of the period covered by our project and the moment of Arrowsmith’s composition. The Synod of Ross, for example, was established in 1707, so was shown on Arrowsmith’s map, but would not have been recognised in the period covered by our project. Similarly, the Synod of Glenelg appears on Arrowsmith’s map, but was not established until 1724. Such challenges meant that it would be remarkably difficult for us to represent the area covered by the Synod of Argyll, in particular, in a single shape file. Then there are changes within the period covered by our project: the Synod of Lothian and Tweeddale includes the region covered by Biggar Presbytery, an area disjoined from the Synod of Glasgow and Ayr in 1644. To capture the complexity of these changes, we would have to create new shape files for each significant revision to the Kirk’s ecclesiastical boundaries. Our shapefiles are no-less an interpretation of provincial synod boundaries than Arrowsmith’s nineteenth century work. Nevertheless, they offer a useful indication of ecclesiastical structures.

Synod boundaries as geoJSON

Once complete, each shape file can be edited further, exported as a GeoJSON (and then possibly converted into other shape file formats) and imported into any mapping platform. Using the workflow we detailed here, we took these datafiles and created a map in Leaflet showing most of Scotland’s provincial synods between 1560 and 1689. For the reasons stated above, we felt it best to not map the Synods of Argyll and Caithness and Sutherland before obtaining further details on their precise extent in the period 1560 to 1689.

Click the thumbnail to see the shapefiles in action

For those interested in making use of these rough shapefiles for their own projects, each file can be found at one of the following links on GitHub:


Angus and Mearns




Glasgow and Ayr

Lothian and Tweeddale

Merse and Teviotdale


Perth and Stirling

These shapefiles are far from perfect — a result of Arrowsmith’s inaccuracies and less-than-perfect drawing on my part — but they represent a start in visually understanding the organisation of the Church of Scotland. And while this represents only a snapshot in time — a more fluid picture would require multiple shapefiles of each synod (especially in Argyll) — such an overview of Scotland’s provincial synods, 1560-1689, shows how scanned images can be georeferenced and then opened up in such a way as to make them machine readable. Tools like Mapping the Scottish Reformation will offer more ways to interpret this messy data.

Chris R. Langley

Leave a Reply

Your email address will not be published. Required fields are marked *