OS MasterMap Imagery Layer
What OS MasterMap Imagery Layer provides you with
Reduce the need for site visits
Using our aerial imagery to check road markings, tree canopies or site entrances cuts down the need for site visits, so you can save money and manage time more efficiently.
Revelation for engineers, surveyors and planners
For engineers, for surveyors, for planners, Imagery Layer is a revelation. It's aligned to OS MasterMap Topography Layer and is incredibly detailed, expertly colour-balanced and corrected for geometric distortions.
Ideal for projects
OS MasterMap Imagery Layer is an off-the-shelf product for the whole of Great Britain. You can get it under perpetual use terms – ideal for projects – as well as fixed-term licences.
Up-to-date imagery and data
OS MasterMap Imagery Layer uses the same source imagery that underpins our large-scale data updates. Our processing software produces true-orthorectified imagery, removing building lean from aerial imagery to give you a consistent top-down view.
Easily interpret the detail
You can easily spot properties with solar panels, conservatories and other home improvements, thanks to the layer's 25cm resolution. This makes the product ideal for planning and environmental monitoring.
Use cases
OS MasterMap Imagery Layer can be used in applications often reducing the need for costly site visits:
- property insurance
- risk analysis
- asset management
- site evaluation
- land-use cover analysis
- agricultural land use and crops inventory
- property management and planning applications
- route planning and accessibility assessments
- location-based services
- vegetation studies and environmental analysis
Additional information
Ensuring the quality of OS imagery
Ordnance Survey has invested considerable resources and worked closely with its imagery suppliers to provide orthorectified imagery that achieves the consistently high quality expected by our customers.
Unlike other data sources, such as topographic data, imagery can be very subjective. It is difficult to quantify specific tolerances for atmospheric conditions, such as haze. We ensure our suppliers adhere to a detailed set of quality levels for the key aspects of imagery with an emphasis on data quality over image appearance alone. For instance priority is given to ensuring detail such as road markings can be seen within shadows and to positional accuracy.
These acceptable quality levels are summarised in the user guide and include:
- the photography and how it is captured;
- the controls and height models used for orthorectification; and
- geometric fidelity (shape), absolute accuracy (position), radiometric accuracy (colour) and image appearance (contrast, haze, cloud cover and distortions).
Active capture programme
More than 97% of our imagery is less than five years old; 90% is less than three years old. Check imagery currency on our interactive map.
OS MasterMap Layers are designed to be used together
As the OS MasterMap Imagery Layer is a raster product, unlike the other (vector) layers in the OS MasterMap product range, TOIDs® are not part of the data specification. However, OS MasterMap layers are designed to be used together in order to create a synchronised tool for analysis of many different types of data in a GIS. Thus other layers can be drawn over imagery to provide information, such as TOIDs.
All imagery since 2015 are 'True' Orthorectified (without building lean)
However, within these images there may be small patches of 'traditional' ortho (with building lean) which have been introduced to resolve geometric or image appearance/artefact issues. Whether 'True' or 'traditional' Ortho, buildings should always be geometrically correct, located in their correct geographical position and suitable for analytical interpretation.
Great care is taken to ensure that the images in the Layer meet our detailed Image Appearance criteria
However, on occasion and under certain circumstances, these rules are relaxed. For example, if opportunities to capture new imagery have been limited by poor weather and existing imagery in the Imagery Layer is deemed out-of-date, then imagery will be accepted provided detail is visible on the ground.In these circumstances, image currency takes precedence over image appearance.