Data SourcesΒΆ

We can put data sources we deal with under the following headings in ascending order of sophistication.

  • Paper map. This will need to be scanned to create a digital image and geographically registered to be usable online. At this level it won't be possible to query the information in any way but it can be made available worldwide for anyone who can read the map to see it set in its correct geographical location relative to other data. Hopefully the legend can be scanned and then this can also be made available.
  • A spatial raster or vector data file with simple properties for each grid point or spatial object. The most common examples are Shapefiles.
  • Spatially enabled database with possibly multiple table joins to particular spatial data fields.

Currently OneGeology only deals with 2D data.

The data fields attached to spatial objects or locations may be numerical but, most commonly, are categorical or descriptive. Most data providers will have their own dictionaries of values for the various categorical properties they describe. In order to aid comparision with other providers data and interoperability with other systems it is helpful to map these local values to some internationally agreed dictionaries of values. There may be a trade-off between precision and wider usability. OneGeology recommends some standard vocabularies for certain properties.

The following levels of harmonisation of vocabularies are of significance in OneGeology:

  • Harmonising age classification and colours used for particular geological ages so that age maps from different providers are comparable.
  • Harmonising lithology classification and colours used so that lithology maps from different providers are comparable.
  • Using CGI (or INSPIRE) standard URI values for age and lithology properties so that the same client (in particular the OneGeology Portal) can query ages and lithologies from different data providers.
  • Using CGI (or INSPIRE) standard URI values for other properties. These aren't currently queried by the OneGeology portal but this provides the potential for other applications to use the data from different providers together.

The main data theme covered by OneGeology is geological map data showing the locations of geological units, faults and other structures. However, it is also increasing the diversity of geologically related themes such as minerals, boreholes, hydrogeology and geoparks.