Alexandria Digital Library Gazetteer Feature Type Thesaurus, with GBH GIS annotations

Table ID:
G_ADL_FT_2015     (57950)
Contents:
Alexandria Digital Library Gazetteer Feature Type Thesaurus, with GBH GIS annotations
Approx. number of rows:
211
Table type:
Codebook
Documentation Author:
Humphrey Southall
Chronology:
The data cover the period 1881 to 1911.

Sources:

  1. This table is essentially a copy of the Alexandria Digital Library project's Feature Type Thesaurus, as created primarily by Linda Hill of the University of California Santa Barbara. At the time of writing (February 2016), even the "legacy" version seems to be no longer available from the ADL site (it was previously at external link: http://www.alexandria.ucsb.edu/gazetteer/FeatureTypes/ver070302/index.htm ) However, a direct copy was available at:

    https://collab.itc.virginia.edu/wiki/toolbox/Alexandria Digital Library Feature Thesaurus.html


Notes:

  1. This table is an exact copy of the table held in the HGIS system at the end of 2015, and is intended as a permanent archive.
  2. This is a formal theasurus, providing a general classification of geographical features organised hierarchically. The broadest term, at level zero, is 'location' and below this are six terms at level one:
    • administrative areas
    • hydrographic features
    • land parcels
    • manmade features
    • physiographic features
    • regions
    Below these are 88 level two terms, 89 level three, 26 level four and one on level five.
  3. Our additions to the ADL content are:
    • The column gbh_name, which is mostly simply a copy of the ADL term but enables us to use labels more appropriate to British English. This has been done for 14 of the 211 terms, including 'ravines' for 'canyons', 'passes' for 'gaps', etc.
    • The column used_by_gbh, flagging those terms we actually used: 104 out of 211.
  4. Although considerable work went into assigning descriptive gazetteer entries to the ADL thesaurus, there are two fundamental problems:
    • Many descriptive gazetteer entries, and most of the longer ones, are explicitly about clusters of features assembled in a "place"; for example, the Imperial Gazetteer describes 'Clun' as 'a river, a small town, a parish, a sub-district, a district, and a hundred'. This led us to construct our 'places' table, behind our place pages, as a deliberately un-typed gazetteer.
    • The ADL thesaurus is wholly inadequate as a classification of British administrative units, providing just four terms for all units below the level of sovereign states (values of gbh_name in brackets):
      • countries, 1st order divisions (nations & regions)
      • countries, 2nd order divisions (counties)
      • countries, 3rd order divisions (districts)
      • countries, 4th order divisions (parishes etc)
      These are insufficient even as a mapping from the geographical levels we record in our Administrative Unit Ontology, which is designed to be indefinitely extensible and (in 2016) defines about 200 kinds of unit, combining types and statuses.


Indices:

IndexTypeColumn(s) indexed
g_adl_ft_2015_pkey Primary key g_adl_ft


Constraints:

The table has the following associated constraints:

ConstraintTypeDetails
g_adl_ft_2015_pkey Primary Key See details above for primary key index



Columns within table:

ColumnTypeContents
g_adl_ft Text string (max.len.=44). Identifier for the term as defined by the Alexandria Digital Library project. These are designed to be human readable, so no separate label is needed.
gbh_name Text string (max.len.=44). Either a copy of the ADL term or a variant more appropriate for British usage.
term_level Integer number. The term's level within the thesaurus.
parent_name Text string (max.len.=44). Identifier for the broader term containing the current term.
parent_level Integer number. Numerical level of the parent term.
used_by_gbh Text string (max.len.=6). 'Y' for rows actually used in classifying our descriptive gazetteer entries, 'N' otherwise.
g_seq Integer number. Sequence number keeping terms in correct order.