Land-Form Panorama from DIGIMAP [OS_1-50K_DEM]
[from EDINA's description of Land-form PANORAMA data:
Land-Form PANORAMA is a digital representation of the contours from
ERS-1/2 Gravity Field Model Product [ERS.ORB.EGM]
The gravitational geopotential produces the principal
acceleration on Earth. Therefore a precise orbit
restitution applying dynamic methods requires a precise
model of the geopotential with resolution ...