160 likes | 377 Vues
Oxfordshire DNF Initiatives. Local Street Gazetteer Property referencing Buried Services Linear referencing. Dave Simmons David C Simmons GIS Consultants. DNF Suppliers briefing February 2006. Before DNF, Oxfordshire had. A locally digitised network–out of step with Ordnance Survey data.
E N D
Oxfordshire DNF Initiatives • Local Street Gazetteer • Property referencing • Buried Services • Linear referencing Dave Simmons David C Simmons GIS Consultants DNF Suppliers briefing February 2006
Before DNF, Oxfordshire had... • A locally digitised network–out of step with Ordnance Survey data. • LLPGs increasingly generating conflicting streets. • Poor communication between county/districts. • No common county/district GIS base. • Drift between UKPMS, EXOR, NSG networks making it very difficult to achieve good asset recording and interoperability. ...Yet resource intensive in both district and county. Ref: Oxfordshire LSG-DNF Case Study
Problems of a mixed gazetteer – different views of streets through parishes and localities • ITN - “Banbury Road” • NLPG suggests splitting into • Banbury Road - Shipton-on-Cherwell • Banbury Road - Thrupp • Banbury Road - Kidlington • Shipton Bottom • NSG may have this split into • Banbury Road - Shipton-on-Cherwell with Thrupp • Banbury Road - Kidlington • (or not split at all) • “Banbury Road” is the common access into each property
… Streets crossing Boundaries… Example:London Road crosses from Oxford City to South Oxfordshire This boundary does not coincide With any junction (Note – for later- the purple WDM Network which relates to links Rather than boundaries)
Building the DNF LSG using ITN • Separate genuine highway streets from “property street placeholders” • Create "ESUs" from ITN (using it as a DNF Base Reference Network). • Identify them using ITN TOID (Link identifier). • Formalise communication between districts and county highways. • Cooperate with OS to improve ITN (using local input allied with strict OS Survey Rules) • Use improved ITN to identify all Highway Streets • Use ITN Road Toids (as associated reference information) and associate 1:1 with USRNs *Note: BS7666 revision is encouraging cross-referencing and classification Ref: Oxfordshire DNF-LSG White Paper
What is an LLPG Placeholder ? • A Street artefact to allow LLPG and LSG to co-exist harmoniously in a “mixed” gazetteer • Very often a “Property Group” (BS DPC part-2 7.5.2) • Not needed to complete highway network • Needed to fill “street slot” in GMS hierarchy • Needed to notionally “split” streets over locality, town or admin area without highway junctions • (Sometimes) needed to implement PAF “dependent street” in GMS IT ATTRACTS NO WORKS NOTICES
A Placeholder- Overmead Green • Overmead Green is • An area of Housing • An LLPG “Street” • It is Accessed from • 2 named streets • 2 unnamed streets • (Note: AddressLayer2 gives each property • Full natural address • A Building Toid • An ITN Link Toid)
How can DNF help streetworks ? • NSG provides USRNs • Many of these are nationally understandable especially in urban areas • Many are defined locally and not well mapped or widely understood • BS7666 part 1 says they are linear and made of Links, but not all are if they have arisen out of BS7666 part 2)… • So … Oxfordshire solution – sort them into highway and non-highway • Only let notices be raised on Highway • Make sure the property attachment to highway is recorded at link level (as in Addresslayer2 ) then you can (often) position works using text in the notices – as in Mayrise - and provide EMPRESS with good information
How can DNF help Buried Services? • Pipelines connect property and run below and across roads, pavements, junctions… • Pipelines can be associated to surface • Pipelines can be associated to highway links • Thus the impact of works on highway and association between works undertakers can improve…
Services around “Overmead Green” • Cold Water is blue • Gas is Yellow • Sometimes they run together • Sometimes traffic is not affected • How do we best use DNF identifiers to help with coordination and notices?
Oxfordshire DNF pilot study area • Purpose is investigation, evaluation and presentation of DNF principles across a wide spectrum of data to support inter-operability • 20km x 20km area including Oxford City • Authorities, agencies, Utilities contributing data • Shown at AGI 2005 DNF Forum • Exploring the application of DNF architecture…
Point Data Reference the link to which the point relates using ID + version number. Give the object an ID, version, classification, and X,Y geometry. Publish an optional offset for lateral position – format to be decided: could be lane number, measure, … Publish an optional chainage for additional information. Eg. A pothole is to be referenced against the transport network. Record object-specific attribution. From DNF Highways Architecture conclusions- 4 Aug 2005
The Integrated Oxfordshire Road Management GIS • ITN provides the base for … • NSG (with potential to support District LLPGs) • “EXOR” Maintenance sections • “MayRise” Streetworks/Streetlighting sections • “WDM” UKPMS Survey sections • Goal is to get all data mapped against ITN base and provided as GIS layers for management and public information • Using DNF linear architecture to relate to ITN Link, with chainage and offset wherever helpful • Preserving as much compatibility as possible with the existing USRNs and WDM /maintenance sections
… Streets crossing Boundaries… Example:London Road crosses from Oxford City to South Oxfordshire This boundary does not coincide With any junction (Note – for later- the purple WDM Network which relates to links Rather than boundaries)
Key messages - “Highway” World reality? • Property occupants use a familiar address for communication • All Properties connect to highway links • Many Properties connect to service links • Some Links form part of named streets • Many Links form part of different network views (eg. UKPMS) • Street works notified by USRN need to somehow be associated to links – (for coordination and diversion planning) • Lighting maintenance uses its own clusters (“streets”) • LLPGs use their own property clusters (“streets”) • Utility gazetteers use their own pipeline clusters (“streets”) • Underground pipes associate to links (traffic impact) and also to surfaces – mutual impact ! DNF can help inter-operability by underpinning and cross-referencing these different world views