[seek-dev] What to do about "nil"
Matt Jones
jones at nceas.ucsb.edu
Tue Nov 9 11:08:34 PST 2004
Hi Rod,
You're right that the data needs to be preserved even when the lat/lon
values are nil -- some people may want to see the rest of the Darwin
Core record for various workflows. However, for the purposes of the
niche model example, I think we want to filter out all records that lack
lat/lon data. So.... maybe the best solution is to fire some sort of
null or missing value code on the lat/lon ports, and then provide a
filter downstream in the workflow that only keeps records that have
legit lat/lon values -- this is what GARP ultimately needs and what
should be saved in the file.
Matt
Rod Spears wrote:
> Here is the schema for Latitude per the DarwinCore spec:
> <xsd:element name="DecimalLatitude"
> substitutionGroup="digir:searchableReturnableData" nillable="true">
> <xsd:annotation>
> <xsd:documentation>The latitude of the location from which
> the cataloged item was collected, expressed in decimal
> degrees.</xsd:documentation>
> </xsd:annotation>
> <xsd:simpleType>
> <xsd:restriction base="xsd:decimal">
> <xsd:minInclusive value="-90.0"/>
> <xsd:maxInclusive value="90.0"/>
> </xsd:restriction>
> </xsd:simpleType>
> </xsd:element>
>
> Note that the value can be "nil" and it also has a restriction. When the
> value reaches the DarwinCoreDataSource as a string it is either a valid
> number within the range or an empty string (length zero).
>
> Currently, I convert the empty string to "0.0" which is the wrong thing
> to do. The question is what should I do? As Dan suggested I could pick
> an arbitray large number and pass that back, but that assumes the
> consumer will know what to do with that value. I could skip any and all
> rows that have empty Lat or Long values, but that may be bad for
> consumers that want to see that data but don't care if it is nil (empty)
> or not.
>
> Any thoughts?
>
> Rod
>
> _______________________________________________
> seek-dev mailing list
> seek-dev at ecoinformatics.org
> http://www.ecoinformatics.org/mailman/listinfo/seek-dev
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Matt Jones jones at nceas.ucsb.edu
http://www.nceas.ucsb.edu/ Fax: 425-920-2439 Ph: 907-789-0496
National Center for Ecological Analysis and Synthesis (NCEAS)
University of California Santa Barbara
Interested in ecological informatics? http://www.ecoinformatics.org
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