Wikidata:Property proposal/georeferencing data

From Wikidata
Jump to navigation Jump to search

georeferencing control point data[edit]

Return to Wikidata:Property proposal/Commons

   Under discussion
DescriptionTabular data file in the Commons Data: namespace containing georeferencing control points for all or part of a Commons old map image
Representsgeoreferencing (Q772007)
Data typeTabular data
DomainCommons image
Allowed valuesData:.+\.gcps(\..*)?\.tab
Example 1File:Pigot_and_Co_(1842)_p2.138_-_Map_of_Lancashire.jpgData:Pigot_and_Co_(1842)_p2.138_-_Map_of_Lancashire.gcps.tab
Example 2MISSING
Example 3MISSING
Sourceuser input via app; also existing data in Commons MapWarper, NYPL MapWarper, British Library Georeferencer, David Rumsey maps, other sites with georeferencing
Planned useMovement of data from Commons MapWarper site to Commons Data namespace; import from external sites
See alsoWikidata:Property proposal/external georeferencer URL

georeferencing pixel mask data[edit]

Return to Wikidata:Property proposal/Commons

   Under discussion
DescriptionTabular data file in the Commons Data: namespace containing the pixel coordinates of the boundary of the georeferenced area
Representsgeoreferencing (Q772007)
Data typeTabular data
DomainCommons image
Allowed valuesData:.+\.mask(\..*)?\.tab
Example 1File:Pigot_and_Co_(1842)_p2.138_-_Map_of_Lancashire.jpgData:Pigot_and_Co_(1842)_p2.138_-_Map_of_Lancashire.mask.tab
Example 2MISSING
Example 3MISSING
Sourceuser input via app; also existing data in Commons MapWarper, NYPL MapWarper, British Library Georeferencer, David Rumsey maps, other sites with georeferencing
Planned useMovement of data from Commons MapWarper site to Commons Data namespace; import from external sites
See alsoWikidata:Property proposal/external georeferencer URL

georeferencing mask geoshape[edit]

Return to Wikidata:Property proposal/Commons

   Under discussion
DescriptionGeoshape containing the georectified latitude and longitude coordinates of the boundary of the georeferenced area
Representsgeoreferencing (Q772007)
Data typeGeographic shape
DomainCommons image
Allowed valuesData:.+\.mask(\..*)?\.)\.map
Example 1File:Pigot_and_Co_(1842)_p2.138_-_Map_of_Lancashire.jpgData:Pigot_and_Co_(1842)_p2.138_-_Map_of_Lancashire.mask.map
Example 2MISSING
Example 3MISSING
Sourcecomputed from pixel mask using georectification based on a particular set of control points
Planned useMovement of data from Commons MapWarper site to Commons Data namespace; import from external sites
See alsoWikidata:Property proposal/external georeferencer URL

Motivation[edit]

Moving Georeferencing data from its present silo in the MapWarper application into the Commons Data: namespace brings it much more naturally into the domain of the Commons community, and will make it much more accessible for use in gadgets or other reuse.

These SDC properties will enable apps to find what has been put where, for the two main types of information used as input for the process; and for queries and apps to access a geoshape showing the real-world position and characteristic boundary of the georectified map.

qualifiers, etc[edit]

Note that multiple sets of control-point (gcps) data may exist concurrently for the same image. Different sets of control points may relate to different maps contained in the image (eg multiple sub-maps; or main map/inset map(s) combinations); to sets of control point data obtained independently from different sources (eg Commons MapWarper / external source); or to control point data obtained from different features for different purposes (eg projection estimation [1] is often most effectively achieved based on control points representing a graticule of intersections of lines of latitude and longitude, whereas final map-warping often aims to distort the map to most accurately place depicted land-features and population centres).

Different sets of control points may be associated with the same or with different pixel masks.

The output mask geoshape will in turn relate to a particular pair of control-point and pixel-mask datafiles.

These potentially complicated relationships can be captured by qualifiers on the statements, in particular parallel applies to part (P518) qualifiers on each of the statements to indicate a particular part of the image (eg main map / top-left map / inset map / second inset map etc), object has role (P3831) to distinguish sets of control points relating to different features; and referencing to distinguish sets of control points with different provenances.

The control-point and pixel-mask statements should also be qualified to associate them with a particular revision-id of the file (Wikidata:Property proposal/image revision-id), in case it may subsequently have been cropped/modified.

The georectified mask should be linked to the inputs it is derived from (Wikidata:Property proposal/based on tabular data). It should also have, for convenience, a P518 to indicate the particular map it relates to, where the image contains multiple maps. Jheald (talk) 06:01, 17 August 2019 (UTC) (revised proposal)

Discussion[edit]

  • Proposed. Jheald (talk) 06:01, 17 August 2019 (UTC)