A primary motivation to join the NGD is likely to be the 
implementation of an application which itself may be 
driven by legislation, economic, commercial or “national 
interest” needs: 
2.5 Applications of the NGD: 
An NGD infrastructure would be of little value if it was 
inaccessible. As we have seen earlier, the provision of 
data encourages usage and innovation by customers. 
Potential applications are many; but three exciting 
examples are worth exploring further can come from the 
National Land Information Service (NLIS), Land Use 
Information Base - England (LUIBE) and agricultural 
subsidy monitoring. 
NLIS is a joint collaboration between HM Land Registry, 
Local Authorities, the Valuation Office and OS. The 
principle aim of NLIS is to provide a land parcel enquiry 
system which can be used for conveyancing and other 
applications. The contributing databases are networked 
(via ISDN lines) and a user is able to make enquiries 
about specific land parcels, their value, ownership, 
planning constraints etc. At the heart of such a system 
are the land and property gazetteers discussed earlier 
which provide cross-referencing from one data providers 
dataset to anothers. 
LUIBE: seeks to extend the current practice of recording 
land use change in England and Wales to the creation of 
a national survey to model and manage land more 
effectively for planning, statistical modelling and other 
purposes. Whereas land cover and land use surveys 
often adopt a raster/grid approach to the survey, LUIBE is 
based on the topographic reference base provided by OS 
data. This has a number of benefits, chiefly it is more 
accurate since polygon boundaries (such as hedges) 
pollute the statistics of grid based systems. Land parcel 
reference systems such as NLIS and other NGD 
applications are able to interrogate land use attributes of 
the polygons of interest (via the gazetteers). 
Agricultural Monitoring: Even with the successful use 
of remote sensing - the European Community subsidy 
monitoring process remains a painstaking process for 
those that have to undertake it. As a minimum, three 
pieces of information are required: 
e the farmers claim/record, 
»« a map defining the land parcels to which the 
claim refers and 
e a processed' remotely sensed image. 
Even with the map overlaid on the image the procedure 
still requires inspection and considerable manual 
intervention. Consider an environment where: 
e each land parcel was uniquely referenced, a 
reference that the farmer was required to 
incorporate in a computer readable form, 
e an on-line gazetteer of land parcels which 
indicated which database the land parcel 
polygon(s) was stored on, 
e and an orthorectified remotely sensed and 
processed image. 
102 
  
Such an application could then be largely automated 
where the retrieved polygon would “cookie cut" the image 
and test against the claim for subsidy - subject to quality 
control and assurance sampling. 
2.6 National Topographic Database 
Much of the specification of OS data products has been 
driven by customers to meet specific requirements, some 
products such as OSCAR have been refocused as 
customers needs have become more clearly defined over 
time. As table 1 demonstrates there are a number of 
databases that service the customer and these 
collectively are known as the National Topographic 
Database (NTD). While the current databases are 
physically connected and coexist in harmony there is 
scope for improvement to eliminate data duplication, 
improve data consistency, data connectivity and hence 
the quality of the end products. 
Work has therefore started in defining a target National 
Topographic Database which fully integrates the existing 
databases and will serve as a platform for new products 
and services from the end of the decade onwards. 
The target NTD is a major piece of work and is Ordnance 
Survey's contribution to the National Geospatial 
Database. The current NTD is already a national 
reference framework for other data collectors/providers to 
tie their information to, by way of the National Grid or 
indirect referencing methods such as addresses. 
Data Themes epoch n: 
Planned Environment : 
Natural Environment 
Built Environment 
Heritage & Historic Env. 
Land Administration & Use 
Socio-Cultural Environment 
Survey & Mapping Process 
National Topographic Database 
Figure 1. The potential scope, data themes and 
relationship of the NGD and NTD. 
3. IMAGERY APPLICATIONS IN SUPPORT OF THE 
NATIONAL GEOSPATIAL DATABASE/NATIONAL 
TOPOGRAPHIC DATABASE 
3.1 introduction 
Geospatial databases require careful management, 
quality control and quality assurance procedures to 
ensure data integrity and fitness for purpose. There are 
challenges in many areas: to reduce expenditure, to 
develop the product portfolio and to deliver new concepts 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996 
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