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GSI Metadata National Draft Bedrock Aquifer Map
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Metadata Date (dd/mm/yyyy): 17/02/2005
Last Date (dd/mm/yyyy): 08/02/2007
Title: National Draft Bedrock Aquifer Map
Description: Definition of the aquifers is based on the aquifer classification developed by Groundwater Section. Some factors used in this classification are hydrogeological, lithological and structural.
Keywords- Bedrock Aquifer, Aquifer Categories, Water Framework Directive, Groundwater, GSI, Geological Survey of Ireland, Bedrock Aquifers
Version : 1.0
Language : English
Data type : vector
Originator org- Groundwater Section (Geological Survey of Ireland)
Other contributors- GSI Bedrock Section
Technical contact details-
Contact Name: Silvia Caloca Casado
Organisation: Geological Survey of Ireland
Contact Address: Information Management,
Geological Survey of Ireland,
Beggar's Bush,
Haddington Road ,
Dublin 4
Contact Email: Silvia.Caloca@gsi.ie
Contact Phone: 016782794
Contact Fax: 016681782
Website Details: http://www.gsi.ie
Principal data capture Technique - Desk study and analysis of field data following the system of bedrock aquifer classification developed by Groundwater Section in the GSI. Some factors used in this classification are hydrogeological, lithological and structural.
4.1 .Filename.- Bedrock Geology of Ireland
This dataset comprises 6 key shape files: Final100kunion.shp, Final100kstra.shp, Final100kstru.shp, Cross100ksection.shp, Final100kmin.shp and 100kpoly.shp.
Date (dd/mm/yyyy) 19/11/2003
Originator Geological Survey of Ireland
Nature of change/update to data
All maps together into a seamless in Arc View . Each map sheet commenced in Arc Info generated new geological coverages representing Stratigraphy, Lithology, Igneous, Diagenetic, Dynamic, Thermal, and Geological Linework. All Arc Info coverages were converted to shapefile format.
Bedrock AutoCAD layers were converted to .dxf format and imported into Arc Info 7.x . For each map sheet Arc Info aml, filtered out relevant Bedrock AutoCAD layers to generate new Arc Info coverages. Each map sheet commenced in Arc Info generated new geological coverages representing Stratigraphy, Lithology, Igneous, Diagenetic, Dynamic, Thermal, and Geological Linework. All Arc Info coverages were converted to shapefile format.
In 2003 it was decided to join all the maps together into a seamless in Arc View, this involved Bedrock, Cartography and Information Technology and Groundwater Section. As the compilation of the series progressed over than a decade, some of the sheet boundaries inevitably did not match due to more recent interpretations as well as minor problems with the rasters not quiet matching. The geological interpretation was “fudged” in order to ensure that boundaries and polygons crossed sheet boundaries where appropriate and joined up.
Cartography introduced Arc GIS 8.x in 2002 to undertake necessary seamless geoprocessing exercise on map sheet-by-sheet basis. The following layers were utilised from original Arc Info coverage map layers: Stratigraphy, Igneous, Lithology, Diagenetic and Geological Linework.
The geological linework was divided into two separate shape files: Structural units and Stratigraphic units.
The original Arc Info coverages had a limited number of fields and did not possess unique code identifier. A new coding system was introduced to establish unique code field called 'NEWCODE'. All Bedrock section's data from their main database at this time (Dataflex) was converted to Microsoft Access. A procedure was then used to join and populate additional records as map sheets were added and merged.
Sheet joins and editing then commenced and quality control checks were introduced at interval and final stages. All relevant symbology was created and customized in Arc GIS. All relevant symbology was created and customized in Arc GIS.
Sources Used as input Data for the Change /update
Data capture & compilation from GSI Field Surveys in 1845 to 2003 performed by Bedrock Section. Data was collected both internally by GSI and also from external data sources.
Data in the form of six inch and one inch maps deposited by exploration companies along with borehole logs and locations were also used in the 1:100,000 compilations (data useful in the midlands Carboniferous).
The 1:100,000 series also used field surveys (mostly 6’’ to the mile) carried out in MSc/PhD mapping made available to GSI by Universities in Ireland and further a field.
Bedrock used AutoCad12 with their red book procedure on creation of geological layers.
CU used cartographic’ software ext. (A customised Arc Info module to facilitate map production process).
CU imported Bedrock data in DXF format and filtered layers in geological thematic GIS ‘coverages’.
Customised aml code was transparent and could be accessed and edited by CU.
Arc Scan ext . performed raster vector conversion preformed by heads up digitising.
Marginalia was greated by aml scripts and generated by Cartography.
Arc Info 7.x and AutoCAD tools.
Final100union.shp, Final100kstra.shp and final100stru.shp were imported into a featured set in an ArcGis Arcinfo 8.3 geodatabase. A topology was created for the final100kunion feature class with rules of “Must Not Overlap” and “Must Not have Gaps” with a cluster tolerance of one metre. Most errors related to the coastline, lakes and river channels. All errors were checked and fixed using the topology toolbar and Editor toolbar leaving 3514 “Must not have gaps” errors. The feature classes were then exported as a shapefile.
Andy Sleeman and Markus Pracht from the Bedrock Section and Eddie McMonagle from the Cartography Section of the Geological Survey of Ireland, Beggars Bush, Haddington Road, Dublin 4.
Date (dd/mm/yyyy).- 11/08/2003
Originator.- Groundwater Section of the Geological Survey of Ireland.
Nature of change/update to data
Twenty-seven Rock Unit Groups were created by grouping over 1200 geological Formations and Members from the original bedrock geology file.
Methodology .- Arc GIS 8.3 Merge and Dissolve options were used to group polygons.
Sources Used as input Data for the Change /update .- Minor errors derived from original file have been detected and they are to be fixed in the future.
Contact details for further information on scripts/Tools.- File created by Taly Hunter Williams, Groundwater Section, Geological Survey of Ireland, Beggars Bush, Haddington Road, Dublin 4.
Date (dd/mm/yyyy).- 13/09/2004
Originator.- Groundwater Section of the Geological Survey of Ireland.
The boundaries of aquifer polygons are based on the bedrock units mapped by the GSI and on the national fracture patterns compiled by Dunphy (2003). The GSI aquifer categories (Rk, Rf, Rg, Lm, Ll, Lk, Pl and Pu) were grouped into four bedrock aquifer types: Karstic (Rk and Lk), Productive Fissured Bedrock (Rf and Lm), and Poorly Productive Bedrock (Ll, Pl and Pu).
Methodology.-
The 100k seamless bedrock map and linework (Final100kunion.shp, Final100kstra.shp and Final100kstru.shp) and also the Rockunit.shp files have been used in order to create the aquifer file. Union and merge options were used. Aquifer polygons have been categorised according to the aquifer classification developed by the GSI Groundwater section.
Sources Used as input Data for the Change /update.-
As new data become available, lithological and structural boundaries may change and aquifer boundaries will change accordingly.
ArcView –Toolbars- Spatial Adjustment and Editor to adjust polygons / ET GeoProcessing Wizards-(To Clean up the polygon file).
Contact details for further information on scrips/Tools .-
File created by Taly Hunter Williams in the Groundwater Section of the Geological Survey of Ireland
Date (dd/mm/yyyy).- 19/07 /2004
Originator.- Groundwater Section of the Geological Survey of Ireland.
Polygons that were “pending classification” in the last draft have now been classified as one of the aquifer classes. Some of the small parts of coastal polygons have been split and classified as non-aquifer (e.g. Sand bars, harbour walls, etc).
Methodology.-
Aquifer classes were assigned to the unclassified polygons. Some polygons along the coastal areas have been edited and readjusted (splitting, cutting, merging).
Sources Used as input Data for the Change /update.-
Previous file (DraftAquifer_0304.shp), aerial photographs, Bedrock Geology etc.
ArcView –Toolbars- Spatial Adjustment and Editor to adjust polygons (cutting
Contact details for further information on scripts/Tools .-
File created by Taly Hunter Williams in the Groundwater Section of the Geological Survey of Ireland
Authorised by : - Koen Verbruggen (IMP, Geological Survey of Ireland)
Maintenance/Update frequency : The Groundwater section takes account of the most up to-date information and hence this file is subject to change. New changes expected to be made soon.
6. Data dictionary; File Name/Field Description/ Field Type
Descript: Description of the unit/ Field type: Text.
Reference system: Irish National Grid
Spatial Extent: Whole of Republic of Ireland and part of Northern Ireland. Full extent in the data's coordinate system:
West longitude: 17937.271188
East longitude: 334513.68825
North latitude: 467259.844302
South latitude: 16333.179178
Additional extent: No height/depth/temporal info
Scale: 1:100,000
Filename: Draft1_July05.shp
Holder: Groundwater Section, Geological Survey of Ireland
Distributor contract details : Silvia Caloca Casado
Information Management,
Geological Survey of Ireland,
Beggar's Bush,
Haddington Road ,
Dublin 4
Storage Format: ArcGIS shapefiles.
Supply Format: ArcGIS shapefiles, MapInfo tabfiles.
Supply media: CD-Rom or email.
File size: 28.6 MB
Copyright: Use of the data is constrained only by the GSI GIS Data License Agreement.
Other restrictions-
Spatial Accuracy: Positional errors of up to 500m have been observed in datasets that have been used to create this file.
Thematic accuracy: Added attributes are thematically correct..
Currency: Digital geometry and attributes are based on the bedrock aquifer classification. Therefore Aquifer boundaries may change according to lithological or structural changes, or new hydrogeological information.
Logical consistency: Data are topologically correct using ArcInfo 8.3.Small gaps have been noticed. Aquifer categories must not only be consistent within RBD's but also countrywide.