Insight User Guide: Historic Mapping
Groundsure possesses the most complete archive of high resolution digitised historical maps in the UK. These are the clearest and highest quality historical maps on the market as they were scanned in colour (where available) and at over 500 dots per inch (DPI), providing greater confidence, clarity and detail.
They also include original marginalia information such as the surveyed, levelled and copyright dates.
Groundsure’s historical maps include National Grid and County Series maps including Town Plans from varied scales and detail: 1:10,000, 1:10,560, 1:2,500, 1:1,250, 1:1,056 and 1:500.
Why this report?
- Maps available as Geotiffs with marginalia
- OS Landline included
- Maps scanned in colour and greyscale
Historical maps are provided in three formats as follows:
- ‘Map Insight’, including town plans: Available scales include 1:10,000, 1:10,560, 1:2,500, 1:1,250, 1:1,056 and 1:500;
- ‘Map Insight (Small Scale)’: available scales include 1:10,000 National Grid and 1:10,560 County Series and now includes mapping from 2001, 2010 and 2019;
- ‘Map Insight (Large Scale)’, including town plans: Available scales include County Series 1:1,056 and 1:500, National Grid at 1:1,250 and both at 1:2,500 and now includes LandLine from 2003.
With each map, a variety of dates will be provided and may include the following:
- Surveyed date: this is the latest date that the survey was examined on the ground. Most county series maps will include at least one date labelled “Survey Date” or similar. It does not always apply to National Grid maps, however.
- Revision date: where a full survey of an area was not required to update the mapping, a revision was undertaken. A revision constituted amendments to the existing data for a map using observations that were substantially less detailed than those used for a full survey. The criteria for how revisions should be carried out changed over time for the OS.
- Edition date: edition is a term that was initially used in the earlier stages of the County Series and usually identifies editions by numbers, i.e. first, second, third and so on. In the majority of cases, there will be an edition date instead of a copyright date.
- Copyright date: use of an explicit copyright date in the margins of the map mostly features in National Grid mapping from the 1960s onward. The date of copyright, for legal purposes, is implicit from a published or edition date. A map is subject to royalties if its copyright date (explicit or implicit) is within the last 50 years. These maps are referred to as in copyright or out of copyright.
- Levelled date: levelling refers to the fixing of altitudes in relation to a datum, which is the mean sea level at a specific geographic point. Levelled dates regularly appear on maps and occasionally the OS will have recorded the original levelling date and all subsequent levelling events. Groundsure currently only records the latest levelling date printed on the map as this is the one most relevant to the map in question.