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6 years ago The seminal MaNIS/HerpNet/ORNIS Georeferencing Guidelines [1], the document Best Practices for Georeferencing [2] and the IJGIS manuscript [3] from which [2] is partially derived describe in detail the interaction between distance and direction in the derivation of uncertainty. The Georeferencing Calculator [4] uses this theoretical basis in practice.
The Best Practices document [2] contains a declaration of the philosophy of "truth in labeling" in section 3.d., which suggests that the uncertainties should always be calculated and given. No arbitrary limit will serve for the myriad unknown uses for the data. Here is the content of that section of the Guide:
"‘Truth in Labelling’ is an important consideration with respect to documenting data quality.
This is especially so where data are being made available to a wider audience, for example,
through the GBIF data nodes. We recommend that documentation of the data and their quality
be up-front and honest. Error is an inescapable character of any dataset, and it should be
recognized as a fundamental attribute of those data. All databases have errors, and it is in noone’s
interest to hide those errors. On the contrary, revealing data actually exposes them to
editing, validation and correction through user feedback, while hiding information almost
guarantees that it remain dirty and of little long-term value. "
[1] Wieczorek, J. 2001. MaNIS/HerpNet/ORNIS Georeferencing Guidelines. Available online at http://manisnet.org/docs/GeorefGuide.html. [2] Chapman, A.D. and J. Wieczorek (eds). 2006. Guide to Best Practices for Georeferencing. Copenhagen: Global Biodiversity Information Facility. Available online at http://www.gbif.org/orc/?doc_id=1288. [3] Wieczorek JR, Guo Q, Hijmans RJ. 2004. The point-radius method for georeferencing point localities and calculating associateduncertainty. International Journal of Geographical Information Science 18: 745–767. [4] Wieczorek C, J Wieczorek (2015) Georeferencing Calculator (version 20160929). Museum of Vertebrate Zoology, University of California, Berkeley. Available: http://manisnet.org/gci2.html.
A user submitted this information via the Darwin Core Hour webform: Timestamp: 11/21/2017 16:06:05 Please provide a topic of interest: When georeferencing from a site description, I think the accuracy would be lower as the point of reference will be farther. Would it be worth trying to do if the accuracy is too low? Should we not fix a limit. It would be even worst if we cannot imagine out the level of appreciation let say when the recorder says 30 kms east of this point, it might mean 90° span (if he classified as E or N,) or 45° (if ENE), Is there anyway to solve that? Are you capable of and interested in participating: No Who else would you recommend to participate in the presentation: Probably georeferencing specialists? What resources can you point to: Geomancer manual may be? Your name: jaona RANAIVO Your email: Your GitHub username: