Catching up on this diverse thread...
I suspect the sources for coordinates the BioBlitz will be phones and GPS receivers. I don't know of any phone application or consumer GPS receiver that provides coordinates in a reference system other than WGS84 by default. As Peter suggests, under these assumptions it would be fine to capture geo:lat, geo:long, and dwc:coordinateUncertaintyInMeters in the field. The expression of these data in Darwin Core would be dwc:decimalLatitude: dwc:decimalLongitude, dwc:geodeticDatum=WGS84 or wc:geodeticDatum=epsg:4326, dwc:coordinateUncertaintyInMeters.
It would be a nice educational exercise to assess the parameters of the devices before starting to use them to take data. What are the accuracies of those phones compared to the GPSs? And of the GPSs compared to reality and to their theoretical (and ephemeral) accuracy readings?
For completeness one could add the other georeference metadata fields meant to provide completeness (strictly for educational purposes, of course), but I won't push it.
I was wondering if something like the following would be an acceptable compromise for those who would like to expose their data using the geo vocabulary.
geo:lat
geo:long
dwc:coordinateUncertaintyInMeters
The idea would be that RDF formatted in this way would be acceptable as DarwinCore.
This would not prevent others from using the traditional dwc vocabulary.
The problem for many is that by using only the dwc version they use the ability to take advantage of many existing tools and api's.
- Pete
On Fri, Aug 6, 2010 at 10:01 AM, joel sachs
<jsachs@csee.umbc.edu> wrote:
All,
When representing observation records in RDF, there are advantages to using Dublin Core and Geo (http://www.w3.org/2003/01/geo/wgs84_pos#)
namespaces where possible. For example, if we use DC:date, and geo:lat, geo:long, instead of DwC:eventDate, DwC:lat, and DwC:long, then Linked Data browsers can automatically map the records, plot them on a timeline, etc.
My question is: What are the disadvantages to doing this? (For example, is this going to break someone's DwC validator?)
Thanks -
Joel.
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Pete DeVries
Department of Entomology
University of Wisconsin - Madison
445 Russell Laboratories
1630 Linden Drive
Madison, WI 53706
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