ITM – GPS Compatible Mapping Survey Ireland 2007, Malahide 15 th May 2007 ITM ITM - - Irish Transverse Mercator Irish Transverse Mercator A ‘GPS’ Compatible Reference System Survey Ireland 2007 ITM Tutorial Colin Bray, Ordnance Survey Ireland
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
ITM ITM -- Irish Transverse MercatorIrish Transverse MercatorA ‘GPS’ Compatible Reference System
Survey Ireland 2007
ITM Tutorial
Colin Bray, Ordnance Survey Ireland
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
• What is ITM?
• Why was ITM developed?
• Irish Grid / ITM comparison
• ITM lineage
• Benefits of ITM
• Implementation Issues
• Transformation utilities
• How can OSi help implementation
• Questions & answers
ITMITM
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
What is ITM ?What is ITM ?
ITM is a GPS compatible mapping system that takes advantage of the accuracy of GPS whilst minimising mapping distortions
– GPS compatible (no transformations required)
– Takes advantage of the accuracy of ETRF89
– Minimises mapping distortions
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
Why was ITM developed?Why was ITM developed?
• Extensive use of GPS in geomatics
• Need for geometric interoperability (GPS & geographic data)
• International compatibility
• Shortcomings of the ‘Irish Grid’
– Legacy distortion issues– Not GPS compatible– Dependant on transformation relationship to GPS– Can only realise IG to better than 1m using GPS
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
IIGG IITTMM
Reference Ellipsoid
Airy (modified)
GRS80
Central Meridian
8° West
8° West
Scale on CM
1.000 035
0.999 820
True Origin ø λ
53° 30' North 8° West
53° 30' North 8° West
False Origin
200 000 W 250 000 S
600 000 West 750 000 South
Mapping System ParametersMapping System Parameters
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
Irish Grid & ITM ComparisonIrish Grid & ITM Comparison
‘Irish Grid’
Mapsheet ‘ITM’
Mapsheet
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
ITM & Irish GridITM & Irish Grid
• 400,000 / 500,000 coordinate difference
• Relationship defined via official OSi / OSNI polynomial transformation
– between ETRF89 and Ireland 1975 (accuracy better than 1m everywhere in Ireland)
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
Development of ITMDevelopment of ITM
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
ITM LineageITM Lineage• 1999 – Concept introduced at ‘Survey Ireland 1999’ conference
• 2000 – Preliminary user information circulated
• 2001 – Consultation paper circulated
• 2001 – ITM Seminar road show (Cork, Belfast, Dublin, Galway)
• 2001 – ITM parameters formally adopted at ‘Survey Ireland 2001’
• 2002 – OSi converts production flowlines to ITM
• 2002/3 – ITM Technical Working Group
• 2002 – ‘Grid InQuest’ transformation utility available
• 2002 – On-line transformation utility available on OSi website
• 2003/7 – ITM presentations at various user groups / conferences
• 2004 – Irish Institution of Surveyors (IIS) recommends ITM adoption
• 2005 – Land Registry goes digital with ITM
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
ITM Consultation ProcessITM Consultation Process
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
IIS Recommends Adoption of ITM to SurveyorsIIS Recommends Adoption of ITM to Surveyors
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
What are the benefits of ITM?What are the benefits of ITM?
• A more accurate coordinate reference system– with the realisation of ETRF89 (IRENET95)
• Geometric interoperability between mapping and modern surveying instrumentation
– Relationship not dependent on transformations
• Mapping distortions are minimised
• International compatibility
• Consistent standard / framework for relating geographic information
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
Implementation IssuesImplementation Issues
• Accessing ITM data
• Viewing ITM data
• Converting between Irish Grid and ITM
• Relating ITM to legacy Irish Grid paper records
• Implementation phases
– Maintain existing Irish Grid geographic records and output in ITM format when required
– Fully implement ITM across all systems and data
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
ITM Technical Working Group (TWG)ITM Technical Working Group (TWG)
Members
• BKS Surveys
• Bord Gais
• Cork City Council
• Electricity Supply Board
• ESBI Computing
• European Air Surveys
• GPS Surveys
• Irish Institution of Surveyors
• Land Registry Ireland
• Land registry Northern Ireland
• LGCSB
• NTL Northern Ireland
• Ordnance Survey Ireland
• Ordnance Survey of Northern Ireland
• Proteus Solutions
• Translink
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
ITM TWGITM TWG
Key Issues
• Data migration
• Grid / sheet indexing
• Legal issues
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
Data MigrationData Migration
Key Issues for consideration
• User education
• Software (vendor products)
• Application developers
• OSi / OSNI datasets
• Raster maps and aerial photography
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
Grid IndexingGrid Indexing
• The ITM TWG recommended a grid index referencing system based on a 1km x 1km grid to be associated with the ITM mapping system
• ITM grid coordinate dimensions:– Min 400,000.000 Easting (m) 500,000.000 Northing (m)– Max 800,000.000 “ 999,000.000 “
• Therefore a 1km x 1km grid index reference system would require a 6-digit numeric to uniquely refer to a specific 1km x 1km grid location (bottom left hand corner)
• Example:– ITM grid coordinate reference = 600,850
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
Legal IssuesLegal Issues
• The only precedent to this situation was the migration of data from the Cassini projection to Irish Grid in the 1960’s
• There is no evidence of any legal issues arising from that transition. As none of the TWG members enquires have identified potential legal difficulties, it was concluded that, at this point in time, there are no obvious legal impediments to the introduction and use of ITM.
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
Data MigrationData Migration
• The main issue affecting successful migration to ITM is project management. The basic migration process is well defined, but requires detailed planning, control and quality assurance.
• If properly planned and managed, the migration to ITM will be equivalent to a complete update of existing third party data, and a new release of software.
• With proper planning, migration to ITM can be achieved within the normal timescales for new releases of software and base datasets
• The involvement of the software application providers and the software developers is key to successful migration
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
Transformation Utilities
Currently available
• Interactive coordinate conversion on OSi website www.osi.ie
• Down loadable coordinate converter shareware from OSi website www.osi.ie
Required
• All major GIS software vendors to implement polynomial transformation
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
How can OSi help with implementationHow can OSi help with implementation
• Providing software application providers and software developers with the required software (DLL & developers manual) to facilitate the implementation of data conversion at the user application end
• Setting up a software application provider / software developer user group to progress their implementation of file conversion utilities
• Facilitating dual supply of ITM & Irish Grid during transitional phase
• Developing a shareware look-up utility that will enable users to easily relate the 1:5,000 sheet index to ITM
ITM – GPS Compatible Mapping
Survey Ireland 2007, Malahide 15th May 2007
Thank you for your attentionThank you for your attention