Circa|Ranges Registry entry

Specify an adjustment (+/-) in years to apply to a date within a given period.

As with Circa a date field can have two associated circa date fields to indicate a period within which an event occurred rather than a specific date. When a date is entered into a date field (preceded by the letter c, e.g. c 1950), the System automatically populates the circa start and end date fields.

For example, if an adjustment of 5 is specified for years between 1900 and 2000, when a date of 1990 is entered, a start date of 1985 and end date of 1995 will be auto-generated.

The user can accept these circa dates or may override them by entering new values.

Usage

This Registry entry can be assigned to users, groups and system-wide:

Key User Group Key System
Key 1 User Group Key 1 System
Key 2 user group Key 2 Setting
Key 3 Setting Key 3 Format
Key 4 Format Key 4 Circa
Key 5 Circa Key 5 Ranges
Key 6 Ranges Key 6 start-end or Default
Key 7 start-end or Default    
Value adjustment Value adjustment
User user Setting Format Circa Ranges start-end or Default adjustment
Group group Setting Format Circa Ranges start-end or Default adjustment
System Setting Format Circa Ranges start-end or Default adjustment

where:

start-end or Default

defines a range of years (separated by a hyphen) that may be entered into a date field. A Default entry defines a default offset for circa dates when a date entered does not fall within a specified date range.

adjustment

is an integer that defines the offset for the circa date fields from the entered year.

Examples

This entry defines an offset of 5 years for any dates entered from 1900 to 1950:

Field Setting
Key 1 System
Key 2 Setting
Key 3 Format
Key 4 Circa
Key 5 Ranges
Key 6 1900-1950
Value 5

If a user enters c 1910 into a date field with an associated circaStart date field and circa End date field, the two fields would be populated with 1905 and 1915 respectively.

This entry defines an offset of 50 years for any dates entered from 500 to 1000:

Field Setting
Key 1 System
Key 2 Setting
Key 3 Format
Key 4 Circa
Key 5 Ranges
Key 6 500-1000
Value 50

It is likely that the circa period will be greater for events occurring a long time ago. For example, if carbon dating is only accurate to the nearest 100 years between the years of 500AD to 1000AD, then the above entry could be used.

Note: These are just default values that the System populates the circa fields with. If the circa range is not appropriate, the user can overwrite the System values with a more valid period.

This entry defines the Default for dates that do not fall within a range specified by a Circa|Ranges entry:

Field Setting
Key 1 System
Key 2 Setting
Key 3 Format
Key 4 Circa
Key 5 Ranges
Key 6 Default
Value 10

If the previous three examples are the only Circa|Ranges entries, and the user enters a date x, where:

  • x < 500
  • x > 1000 but < 1900
  • x > 1950

the System will set the circa dates to be 10 years either side of the given date x.