Locality

A locality is a specific place associated with one or more Collecting Events.  Ultimately, each locality should be a unique circle in geographic space.  The center is a point defined by latitude and longitude, and the radius is a linear estimate of error.  For electronic mapping, we convert such data to decimal degrees with estimates of error in meters.  Interfaces to the data are more flexible.

A locality is a specific place associated with one or more Collecting Events.  Ultimately, each locality should be a unique circle in geographic space.  The center is a point defined by latitude and longitude, and the radius is a linear estimate of error.  For electronic mapping, we convert such data to decimal degrees with estimates of error in meters.  Interfaces to the data are more flexible.

A locality includes three types of data

Some caveats:

Locality Nickname

Locality Nickname is a globally-unique human-readable “locality ID” commonly used to unambiguously associate one or more specimens to a locality. Named Localities:

  1. Will not be auto-deleted when not used
  2. Will always be unique, so will not be auto-merged

Specific Locality

Locality . Spec_Locality VARCHAR2 (255) null

refers to the locality from which the specimen was collected from the wild, regardless of whether the animal was brought into captivity and killed at a different time and place.  If the wild-caught locality is not known, put the location where the animal died, was killed, or was purchased (e.g., the zoo, aviary, pet store, lab, or market) in the Specific Locality field (see Collecting Events for more details).

  1. When writing Specific Localities, the highest priority should be to maximize clarity and minimize confusion for a global audience.  Do not include higher geography (continent, ocean, sea, island group, island, country, state, province, county, feature) in the Specific Locality unless it references a place-name in another geopolitical subdivision, in which case include that subdivision in parentheses. The following example is located in California.

Elevations


Locality . Maximum_Elevation

Locality . Minimum_Elevation

NUMBER null



Locality . Orig_Elev_Units VARCHAR2 (2) null

ctorig_elev_units

are a height above mean sea level.  If elevation data are part of the verbatim locality, they should be entered into Minimum Elevation, Maximum Elevation, and Elevation Units (ft, m).  If the Verbatim Locality contains a range for an elevation, e.g., 500-600 ft, these values should be entered into the minimum and maximum elevation fields, respectively.  If a single elevation is given in Verbatim Locality, put that value in both the minimum and maximum elevation fields.

Depths


Locality . Max_Depth

Locality . Min_Depth

NUMBER null



Locality . Depth_Units VARCHAR2 (2) null

ctdepth_units

are a distance below the surface of a body of water.  The body of water may or may not be at sea level, e.g., a mountain lake.  If depth data are part of the verbatim locality, they should be entered three fields for elevation: Minimum Depth, Maximum Depth, and Depth Units (ft, m).  If the verbatim locality contains a depth range, e.g., 500-600 ft, these values should be entered into the minimum and maximum depth fields, respectively.  If a single depth is given in the verbatim locality, put that value in both the minimum and maximum elevation fields.

TRS

Township, Range, and Section (TRS) information is sometimes given for localities.  TRS data should be entered as (part of) Specific Locality, and optionally converted to coordinates. A thorough description of TRS data, along with a tool to translate them to latitude and longitude can be found at the following URL:

www.esg.montana.edu/gl/trs-data.html.

Coordinates

The assigning of latitudes and longitudes to verbal locality data is called georeferencing. Latitude describes a position in degrees north or south of the equator. Longitude describes a position in degrees east or west of the Greenwich meridian. However, coordinates alone are of limited use without information on uncertainty and the coordinate frame of reference (datum).

Protocols for georeferencing natural history collections are described in the MaNIS Georeferencing Guidelines.  Tools that automate these protocols include the Georeferencing Calculator, BioGeomancer, and GeoLocate.  GeoLocate is called as a web service by applications within Arctos.

Coordinates are stored with collecting events and with locality, both optional. Collecting event coordinates are “verbatim” and should reflect some data associated with specimen events. Locality coordinates are part of georeferences, and may be standardizations or corrections of, or additions to verbatim coordinates.

Any locality has zero or one coordinate assertions. “Unaccepted coordinates” are handled by having multiple specimen events referencing multiple localities.

Data Entry has (for brevity) one place for coordinate information, and these data are stored as both verbatim and locality coordinates. Events and localities may be pre-made and selected when these limitations prevent accurately representing the data.

Original Units

collecting_event . Orig_Lat_long_Units VARCHAR(20) null

ctlat_long_units

DarwinCore2=VerbatimCoordinateSystem

for geographic coordinates vary with the source of the data.  Classically, latitude and longitude have been recorded in degrees, minute and seconds.  Now, modern GIS applications generally use degrees only, including decimal fractions for all levels of precision.  In Arctos, coordinates are stored and displayed in their original format.  Except for UTMs, coordinates are also translated to, and stored as, decimal degrees for standardization and mapping.  There is not yet programming to convert UTMs to decimal degrees. Include as many digits of precision as are provided in the original data.  Forms in Arctos are customized according to which format is chosen, and the vocabulary and formats are defined and described by a code table.

In all formats, include as many digits of precision as are provided in the original data.

(Geodetic) Datum

Collecting_Event . Datum VARCHAR(40) null

ctdatum

DarwinCore2=GeodeticDatum

The geodetic datum to which the latitude and longitude refer. A geodetic datum describes the size, shape, origin, and orientation of a coordinate system for mapping the earth. Latitude and longitude data referenced to the wrong datum can result in positional errors of hundreds of meters. Therefore, when providing latitude and longitude data, it is important to know from which datum those data are derived. Most GPS units allow you to select the geodetic data from which its coordinates will be determined (default usually set to WGS84, but this should be checked in the field). Maps and gazetteers generally provide this information as well.

Reference Source

Locality . GEOREFERENCE_SOURCE VARCHAR(255) not null

ctGEOREFERENCE_SOURCE

DarwinCore2=GeoreferenceSources

refers to the source(s) of the coordinates and not to the source of the error. Coordinates may be original data collected with the specimen, or they may be provided by after-the-fact georeferencing efforts. In the latter situation, data in Source(s) should be specific enough to allow anyone in the future to use the same resources to validate the coordinates, or to georeference the same locality. These data might be a list of maps, gazetteers or other resources used to georeference the locality. Examples:

In cases where the coordinates are original data, a description of the original source should be provided. Again, these data should make the coordinates as verifiable as possible by referring to records associated with the specimen. Examples:

Georeference Method

Locality.GEOREFERENCE_PROTOCOL VARCHAR(40) not null

ctGEOREFERENCE_PROTOCOL

is the protocol used to obtain the values for the coordinates and the measure of precision. Different methods and tools have been produced, and are sometimes revised, and these differences can produce different results.  The vocabulary for this field is controlled.

Maximum Uncertainty Distance

Lat_Long . Max_Error_Distance NUMBER null

DarwinCore2=CoordinateUncertaintyInMeters

Lat_Long . Max_Error_Units VARCHAR2(2) null

ctlat_long_error_units

is the upper limit of the horizontal (as opposed to elevational) distance from the reported latitude and longitude. It describes a circle within which the whole of the described locality lies. Leave the value empty if the uncertainty is unknown, cannot be estimated, or is not applicable (because there are no coordinates). Zero is not a valid value. Maximum Uncertainty is the sum of GPSAccuracy, Extent, and all other sources of error or imprecision.

This is a simple concept, but there are several sources of error which, when correctly combined, often demonstrate a value larger than intuition might suggest. These sources of error are enumerated in the MaNIS Guidelines, and are combined into estimates of total error by the Georeferencing Calculator.

In some circumstances the greatest source of error is the behavior of the collector and/or any intermediary sources of the data. For example, if a locality names a village, the collector may have obtained specimens from a resident who forages over a large area near the village. The collector may even have provided coordinates for the village, often from some standard source, implying specificity equal to the extent of the village. Estimating error can therefore be subjective, and conservative interpretation demands large values for Maximum Uncertainty. To avoid ambiguous or misleading locality descriptions, see MVZ’s guidelines.

Note that there is no error inherent to coordinates. {Dec_Lat=12,Dec_Long=34} is precisely the same point as {Dec_Lat=12.000000000000000000000000000000,Dec_Long=34.000000000000000000000000000000}. Make no assumptions of coordinate error or “size” (all coordinates describe a point) based on anything other than asserted maximum error.

For most usage, including exportation to federated portals, the value for Maximum Uncertainty is converted from the original units (recorded here) to the value in meters.

Remarks

Lat_Long . Lat_Long_Remarks VARCHAR2(4000) null

DarwinCore2=GeoreferenceRemarks

about the spatial description determination, explaining assumptions made in addition or opposition to the those formalized in the method referred to in Georeference Method.

WKT Polygon

provides for a well-known text shape associated with locality data.

Edit Locality Form

Localities used by “verified by….” verificationstatus values may not be edited. If you don’t understand the giant bright red box, please use a contact link.

Many things are paired or dependant. Min, max, and units must be given together for elevation and depth. Coordinates must have datum, source, and protocol. Error cannot exist without coordinates. Fieldset labels on the form will change as form values change to help inform you of these associations.

All coordinates are stored as DD.ddd format. (Verbatim Coordinates are an attribute of Collecting Events.) The form will make conversions.

The webservice data pane has documentation inline. Read it.

Maintenance

Duplicate localities are automatically merged, and unused localities are automatically deleted. A Locality Nickname will prevent both of these actions and should be used in pre-created localities. Please remove nickname from any localities which you no longer intend to use.