GSI Physiographic Units Level 2

Theme: Science
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Physiographic maps are cartographic representations of the broad-scale physical landscape units of a region, and physiographic units consist of physical regions showing internal uniformity with respect to one or more environmental attributes, which are clearly differentiated from neighbouring regions. This dataset presents a physiographic units map for the Republic of Ireland. The units were mapped at 1:100,000 scale in order to be represented as a cartographic digital map at 1:250,000 scale. A hierarchical classification system was derived in order to provide representations of the landscape physiography at different levels of complexity. Level 2 classification scheme differentiates between fifteen landform systems comprising, seven bedrock dominated landscape with differing texture or rugosity, which is strongly associated with the underlying bedrock type (e.g. granite bedrock evolves into rounded mountain or hill landscapes, quartzite ....) and eight sediment landscapes with differing landform signatures, which are indicative of the geological process shaping them.

Data Resources (5)

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Theme Science
Date dataset released 2018-04-11
Date dataset updated 2018-04-12
Dataset conforms to these standards The INSPIRE Directive or INSPIRE lays down a general framework for a Spatial Data Infrastructure (SDI) for the purposes of European Community environmental policies and policies or activities which may have an impact on the environment.
Rights notes ['Creative Commons license conditions apply', '', 'license', '', 'license']
Update frequency Other
Language English
Landing Page
Geographic coverage in GeoJSON format {"type":"Polygon","coordinates":[[[-11.0, 50.0],[-11.0, 56.0], [-5.0, 56.0], [-5.0, 50.0], [-11.0, 50.0]]]}
Spatial Reference Systems (SRS) TM75 / Irish Grid (EPSG:29903)
Vertical Extent {"maxVerticalExtent": "1041", "verticalDomainName": null, "minVerticalExtent": "0"}
Provenance information Originator - Quaternary and Geotechnical Section, Land Mapping Unit, Geological Survey Ireland. The physiographic units dataset was constructed from visual analysis and interpretation of four main digital data sources: (1) Geological Survey bedrock geology maps at 1:100,000 and 1:500,000 scale; (2) Geological Survey Quaternary sediments and geomorphology maps at 1: 50,000 scale; (3) Hydrographically corrected DEM with 20 m pixel size (EPA) and 5 m pixel size DEM (Ordnance Survey Ireland, OSI); (4) High resolution digitalglobe orthophotography dataset and national digital premium basemap map service cached from 1:4,000,000 to 1:1,000 scale (OSI). The visual analysis within a GIS environment of the datasets coupled with expert judgement was used to delineate the outline of the discrete physiographic units through an iterative process where early iterations of mapping results were assessed and discussed by the working group to reach final the version of the dataset. The mapping methodology was tested and refined in three main steps: (1) Delineation of physiographic units for three pilot areas at scales ranging from 1:30,000 to 1:100,000 with the objective of generating a final dataset to be used at 1:250,000 scale. (2) Construction of a nationwide map which extended the first step above, focussing on the delineation of physiographic units across the entire country based on DEM topography, Quaternary geomorphology, Quaternary sediments and bedrock datasets as listed above, followed by further development and definition of the classification scheme. (3) Merging and reclassification of some physiographic units into three levels of complexity, as well as the detailed, local-scale editing of their outlines based on changes on slope and altitude thresholds, as identified from slope and altitude maps constructed from DEMs.