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OSI Discovery Series - OSI document.
Submitted by hilladmin on Fri, 01/05/2009 - 17:04.
The Ordnance Survey or Ireland (OSi) wish to bring out a revised 1:50000 map series. As part of a consultation exercise they have asked the public for their opinion on various issues. One of these is that they wish to use the ITM grid for Ireland which is somewhat different from the existing "Irish Grid" (It's proper name is TM75). The text of this document comes from a short description produced by OSi on 30 Apr 2009.
If you are interested in attending a consultative meeting with OSi Click Here
Discovery Maps with ITM coordinates
Ordnance Survey Ireland (OSi) intends to begin publishing discovery maps using Irish Transverse Mercator (ITM) coordinates during 2009. At present OSi collects and stores all it’s mapping data in ITM and where required converts to Irish Grid. Obviously this is an extra process that OSi has to complete.
What is ITM?
Irish Transverse Mercator or ITM is a GPS compatible coordinate system that takes advantage of the accuracy of GPS whilst minimising mapping distortions.
Changes to the Paper Map Series
Map Layout
• The number of sheets in the series will be reduced by 20 to 69 sheets.
• The map sheet area for each sheet will increase to 40x40k
• There will be no overlaps between sheets
• The sheet layout will directly match the digital 20x20 k digital tile matrix.
How will I recognize a map using ITM coordinates?
• It will have a clear new presentation.
• The sheet will be printed both sides. Physically it will be a smaller sheet of paper therefore easier to handle.
• It will have both ITM and IG grid values displayed at regular intervals.
Why is OSi moving to this grid system?
• A more accurate coordinate reference system
– ITM & GPS both based on ETRF89 (Irish Gird is not)
• Compatibility with GPS
• Improved Positional Accuracy
• International Compatibility
What impact will it have on my use of your mapping?
Maps will look exactly the same but the coordinates printed on the edges of the map will be in ITM instead of Irish Grid. ITM coordinates begin at 400,000, 500,000 the size of each map will be larger and therefore the number of sheets required to cover Ireland will be less
When will OSi start publishing maps using ITM coordinates?
OSi expect to begin publishing maps for general consumption in the latter part of 2009. We expect to have a small number of this new series available for the Christmas market. The generation of a completed series will take two years to complete.
OSI Overall Grid Diagram
Will there be a transitional phase for the implementation of the new maps?
OSi will publish the first ITM discovery maps with both coordinate grid systems displayed on map edges.
Townlands
The new "D" edition of OSNI's Discoverer series, the equivalent of OSI's Discovery, has a map of townlands on the reverse. This represents a great leap forwards and is getting very positive comment from people interested in language, history and culture. Previous to this only an apparently random selection of townlands was marked on the maps and the boundaries were not shown. As the size and shape of townlands varies enormously, the old editions gave a very unreliable impression of the location of townlands, and many were not shown at all.
I understand that OSI has plans to make its new maps double-sided. Is that because they are going to follow the lead of OSNI on this, or is it so that they can put half the normal map on each side? Should I cheer or sigh?
Paul T