4. Appendices
2.2 Spatial Data and Other Information
This section explains the additional non-address related information that the ECAD provides.
There are four tables:
Spatial Information, i.e. geographical co-ordinates
Extra non address related Building Information
Extra non address related Organisation Information
Administrative Information, i.e. local authorities.
The main link between these additional information tables and the address type entities will be the primary key of these Address Tables, i.e. BUILDING_ID, THOROUGHFARE_ID, etc.
Each of the four additional information tables has a list of address types which it supports. For the included Address Tables, you can simply use the primary key of the Address Table to look up information in the respective tables by linking to its primary key; ECAD_ID.
Figure 1 Example of how sample Address Tables link to SPATIAL_INFO table using primary keys.
Table Name Address Tables SPATIAL_INFO Building
Building Group Thoroughfare Locality Post Town County BUILDING_INFO Building ORGANISATION_INFO Organisation ADMINISTRATIVE_INFO Building POSTAL_INFO Building
The data in these tables is updated independently from the address related tables. Each table has their own LAST_UPDATED and CREATED_DATE columns to reflect these changes.
In the next sections the above Additional Information Tables are described in more detail, listing the columns and descriptions for each.
2.2.1 Spatial Data
The ECAD supports multiple geographical co-ordinate options for mapping locations. These co-ordinates are available as Easting/Northing or Latitude/Longitude depending on the reference system used.
The following geographic co-ordinate systems are currently supported in the ECAD:
Irish National Grid (Easting/Northing)
Irish Transverse Mercator (Easting/Northing)
ETRS89 Reference System (Latitude/Longitude)
These are described in more detail below and further detail can be found on the Ordnance Survey website (www.osi.ie).
Figure 1 in section 2.2 shows how to join to the SPATIAL_INFO table to get coordinates given a specific ECAD_ID (e.g. ORGANISATION_ID, BUILDING_ID, THOROUGHFARE_ID, etc.) To get a coordinate for an Eircode you simply link ADDRESS_POINT.BUILDING_ID = SPATIAL_INFO.ECAD_ID, bearing in mind that SPATIAL_ACCURACY = 4 means the coordinate is unreliable. To perform the link from the POSTAL_ADDRESS table, you simply link the POSTAL_ADDRESS.BUILDING_ID = SPATIAL_INFO.ECAD_ID.
2.2.1.1 Spatial Accuracy
The accuracy of the geo-coordinate provided for a building is determined by An Post based on the source of the information and the methodology employed. The accuracy levels are described in the following table:
ACCURACY LEVEL DESCRIPTION
1 – OSI MAP This is the highest level of accuracy. The position has been determined by Ordnance Survey Ireland using their most up to date mapping. The position is located in the centroid of the building outline.
2 – OSI ORTHO The position has been determined by Ordnance Survey Ireland using ortho photography.
3 – GENERAL An initial approximate position has been generated by An Post 4 – UNVERIFIED The co-ordinates provided, if any, have not been certified by the
source provider. This means that the final quality control process has not been completed, and you should not rely on the accuracy of the provided co-ordinates.
NOTE:
Prior to the Q217 release Eircodes were assigned to new buildings as required, independent of the Spatial Accuracy of the building in which they were contained. From Q217 release onwards Eircodes are not assigned to addresses where the Spatial Accuracy is Unverified (value=4). However, there are still Eircodes in the database within buildings that have unverified coordinates for the following reasons:
1. Existing Eircodes whose buildings are still unverified
2. Existing Eircodes moved to buildings that are now unverified
The second category of Eircodes were displayed on a map in previous versions of Eircode Finder. As the buildings they are now in have unverified coordinates, these Eircodes are not displayed on a map in Eircode Finder.
2.2.1.2 Specific Geo-coordinates Vs. Bounding Box Geo-coordinates
For buildings, the SPATIAL_INFO table contains geo-coordinates for the specific building location. For the remaining address types that encompass multiple buildings the specific geo-co-ordinate fields contain statistical mean values of the geo-co-ordinates and also bounding box information. The bounding box fields contain the minimum and maximum coordinate values for all the buildings associated with the address.
The SPATIAL_INFO table has the following fields:
FIELD INFO DESCRIPTION
ECAD_ID Unique 10 digit identification number ING_EAST Irish National Grid Easting Co-ordinate ING_NORTH Irish National Grid Northing Co-ordinate
ITM_EAST ITM Easting Co-ordinate
ITM_NORTH ITM Northing Co-ordinate
ETRS89_LAT ETRS89 Latitude Co-ordinate ETRS89_LONG ETRS89 Longitude Co-ordinate
ING_MIN_EAST Irish National Grid Minimum Easting Coordinate ING_MIN_NORTH Irish National Grid Minimum Northing Coordinate ING_MAX_EAST Irish National Grid Maximum Easting Coordinate ING_MAX_NORTH Irish National Grid Maximum Northing Coordinate ITM_MIN_EAST ITM Minimum Easting Coordinate
ITM_MIN_NORTH ITM Minimum Northing Coordinate ITM_MAX_EAST ITM Maximum Easting Coordinate ITM_MAX_NORTH ITM Maximum Northing Coordinate ETRS89_MIN_LAT ETRS89 Minimum Latitude Coordinate ETRS89_MIN_LONG ETRS89 Minimum Longitude Coordinate ETRS89 _MAX_LAT ETRS89 Maximum Latitude Coordinate ETRS89 _MAX_LONG ETRS89 Maximum Longitude Coordinate SPATIAL_ACCURACY Describes Accuracy Level of Geo-Coordinates CREATED_DATE Date Created for the record
LAST_UPDATED Date Updated for the record
2.2.1.3 Irish National Grid
The Irish National Grid reference system was derived by the Ordnance Survey of Ireland, it is a plane co-ordinate system based on a modified Transverse Mercator Map Projection on the Airy Modified ellipsoid.
Within the grid any location can be mapped using two dimensions Easting (E) and Northings (N) relative to the false origin. The Irish grid false origin is originated at 200 kilometres west and 250 kilometres south of true origin. The true origin is located at Latitude: 53°30'00 N and Longitude: 8°00'00 W.
2.2.1.4 Irish Transverse Mercator (ITM)
ITM is a new co-ordinate system devised for Ireland jointly implemented by the Ordnance Survey of Ireland (OSI) and the Ordnance Survey of Northern Ireland (OSNI) in 2001. The name is derived from the Transverse Mercator projection it uses.
It maintains the true origin and central meridian as set in the Irish National Grid but has a different False Origin, thus distributing the differences between the previous National Irish Grid distortions due to the projection evenly.
2.2.1.5 ETRS89 European Terrestrial Reference System
The European Terrestrial Reference system is a precise subset of the IRTF (International Terrestrial Reference Frame) with geographic co-ordinates (latitudes and longitudes) based on the GRS80 ellipsoid and has become the adopted reference system for Europe. The ETRS coordinates provided have been calculated from ITM coordinates using MapInfo Professional version 12.
2.2.1.6 WGS84 Reference System
The Reference System WGS84 is commonly used with GPS devices. It and the European Reference System ETRS89 are virtually identical and Coordinate Transformation between the two systems is unnecessary as the positions calculated by these two Reference Systems currently deviate by far less than one metre.
2.2.2 Additional Building Information
The following table lists the fields available in the BUILDING_INFO table. The unique identifier for this table is the BUILDING_ID which is the primary key of the BUILDING table.
FIELD INFO DESCRIPTION
BUILDING_ID Unique 10 digit identification number for the Building.
BUILDING_TYPE_ID The Type of Building e.g. Bungalow, Detached etc.
HOLIDAY_HOME A Yes/No field, indicating whether or not the building is a holiday home. NOTE: This field was not populated prior to Q120 release..
UNDER
CONSTRUCTION
A Yes/No field, indicating whether or not the building is under construction.
BUILDING_USE R- Residential, C-Commercial, B-Both or U-Unknown.
VACANT A Yes/No field, indicating whether the building is vacant.
CREATED_DATE Date Created for the record.
LAST_UPDATED Date Updated for the record.
2.2.3 Additional Organisation Information
The following table lists the fields available in the ORGANISATION_INFO table. The unique identifier for this table is the ORGANISATION_ID which is the primary key of the ORGANISATION table.
FIELD INFO DESCRIPTION
ORGANISATION_ID Unique 10 digit identification number for Organisations VACANT A Yes/No field, indicating whether the organisation is
vacant.
NACE_CODE The NACE Code for the Category. NOTE: This field was not populated prior to Q120 release.
NACE_CATEGORY Name of the NACE Category. NOTE: This field was not populated prior to Q120 release.
CREATED_DATE Date Created for the record.
LAST_UPDATED Date Updated for the record.
NACE CODE
The NACE (Nomenclature of Economic Activities) Classification list for economic activities is divided into separate categories such as Manufacturing, Agriculture, etc.
2.2.4 Additional Administrative Information
The ADMINISTRATIVE INFO table contains additional generic information for different types of ECAD Address Information Entities. The ADMINISTRATIVE INFO table has been populated using boundary data sourced from https://data.gov.ie website. The ITM coordinates for Buildings have been used in SQL Server 2016 to apply the ID’s to the table.
The ECAD ID relates to the BUILDING_ID of the Building table.
FIELD INFO DESCRIPTION
ECAD_ID Unique 10 digit identification
LA_ID Unique Identifier for Local Authority 2017 data
DED_ID Unique Identifier for Electoral Divisions 2017 data
SMALL_AREA_ID Unique Identifier for the Small Area 2017 data
TOWNLAND_ID Unique Identifier for townland 2017 data GAELTACHT_ID Unique Identifier for the 7 Gaeltacht
areas 2017 data
LA_2015_ID Unique Identifier for Local Authority 2015 data
DED_2015_ID Unique Identifier for Electoral Divisions 2015 data
SMALL_AREA_2015_ID Unique Identifier for the Small Area 2015 data
TOWNLAND_2015_ID Unique Identifier for townland 2015 data GAELTACHT_2015_ID Unique Identifier for the 7 Gaeltacht
areas 2015 data
CREATED_DATE Date Created for the record LAST_UPDATED Date Updated for the record
NOTE:
The Q317 release of Eircode Address Database uses updated boundary data. The values in the existing fields have been overwritten with the latest data. To assist Eircode Address Database users in upgrading their information in a controlled manner, we have appended
additional columns to the table that will continue to be populated with the existing dataset (2015).
The field identifiers map to the source data on https://data.gov.ie as follows:
FIELD INFO SOURCE
DED_ID https://data.gov.ie/dataset/electoral- districts-boundaries-ungeneralised-osi-national-administrative-boundaries/
Field: Ed_id
SMALL_AREA_ID https://data.gov.ie/dataset/small-areas- ungeneralised-osi-national-statistical-boundaries/
Field: Objectid
TOWNLAND_ID https://data.gov.ie/dataset/townland- boundaries-ungeneralised-osi-national-statutory-boundaries
Field: Td_id
GAELTACHT_ID https://data.gov.ie/dataset/gaeltacht-boundaries-ungeneralised
Field: Objectid_1
LA_ID Derived from the first two characters of Csoid field of Small Area dataset, field values as per table below
Local Authority
There are 31 local authorities in Ireland including 26 county councils, 2 city and county councils, and 3 city councils. Local authorities are multi-purpose bodies charged with the responsibility for a large range of services within their area, e.g. Housing, Planning, Roads, etc.
LA_ID LOCAL AUTHORITY
1 CARLOW
2 CAVAN
3 CLARE
4 CORK
5 DONEGAL
6 GALWAY
7 KERRY
8 KILDARE
9 KILKENNY
10 LAOIS
11 LEITRIM
12 LIMERICK
13 LONGFORD
14 LOUTH
15 MAYO
16 MEATH
17 MONAGHAN
18 OFFALY
19 ROSCOMMON
20 SLIGO
21 TIPPERARY
22 WATERFORD
23 WESTMEATH
24 WEXFORD
25 WICKLOW
26 SOUTH DUBLIN
27 FINGAL COUNTY COUNCIL
28 DUN LAOGHAIRE
29 DUBLIN CITY
30 CORK CITY
31 GALWAY CITY
Electoral Divisions
Electoral Divisions (ED) are legally defined administrative areas in Ireland. There are 3,441 Electoral Divisions. Electoral Divisions are sub-divisions of Counties.
Small Area
Small Area boundaries are sub-divisions of Electoral Divisions and offer a much greater level of detail in terms of analysing data spatially. A normal Small Area is comprised of approximately 80-120 dwellings created by the National Institute of Regional and Spatial Analysis (NIRSA) on behalf of the Ordnance Survey Ireland (OSi) in consultation with the Central Statistics Office (CSO). CSO’s Census 2016 publishes SAPS at the Small Area level.
There are 18,641 Small Areas in the ECAD.
Townland
A townland is a small geographical division of land commonly used in Ireland and form the building blocks for higher-level Electoral Divisions.
Townland names may not be unique within a County.
2.2.5 Additional Postal Information
The following table lists the fields available in the POSTAL_INFO table. The unique identifier for this table is the BUILDING_ID which is the primary key of the BUILDING table.
FIELD INFO DESCRIPTION
BUILDING_ID Unique 10 digit identification number for the Building.
POSTAIM_PRESORT_61 An Post sorting information.
POSTAIM_PRESORT_152 An Post sorting information.
PUBLICITY_POST_ZONE An Post publicity post zone information.
CREATED_DATE Date Created for the record.
LAST_UPDATED Date Updated for the record.
This data relates to services provided by An Post. Please see www.anpost.com for further detail regarding this information.