Artifacts
Artifacts are the items being seriated. OptiPath has been developed as a tool in archaeology although it can be used in other fields as well. In deference to archaeologists, we use the term 'artifact' rather than 'object' or 'item'. Archaeologists often deal with collections, or assemblages, of artifacts rather than individual artifacts. OptiPath can work with collections as individual artifacts, or it can build assemblages from individual artifact data.
The object of seriation is to determine an ordering, or seriation, of a number of objects, or "artifacts", that replicates as closely as possible their historical order of creation. To do this, OptiPath relies on the assumption that the artifacts share characteristics or features whose measure evolves gradually over time. The ordering of artifacts that produces the most gradual evolution of all features for all artifacts is considered the optimal seriation.
By choosing Assemblages in the seriation parameters
or by selecting Artifacts | Use Assemblages from the OptiPath main menu
or by clicking the Assemblages button
on the
toolbar, you can direct OptiPath to classify
individual artifacts by their assemblage and then seriate the assemblages rather
than the artifacts themselves. See Assemblages.
The Assemblages button is a toggle, being replaced by the Artifacts button
when you are currently using
assemblages.
The Artifacts menu contains a number of items:
Edit - allows you to open the artifacts table and create, delete and edit the artifacts and edit their parameters.
Include All - allows you to include all excluded artifacts in the next seriation.
(Don't) Use Assemblages - a toggle that allows you to (not) use assemblages in your next seriation. Not using assemblages is equivalent to using artifacts. This item toggles between Use Assemblages and Don't Use Assemblages. There are corresponding Use Assemblages
Show (Hide) Data - a toggle that specifies whether artifact feature data is to be displayed in the artifacts table. This item toggles between Show Data and Hide Data. This menu item is disabled if the artifacts table is not open.
Show (Hide) Results - a toggle that specifies whether seriation results are to be displayed in the artifacts table. This item toggles between Show Results and Hide Results. This menu item is disabled if the artifacts table is not open.
In the Artifacts table you may add, edit and delete artifacts and edit their data. There are a number of attributes associated with each artifact:
Exclude - this parameter allows you to exclude an artifact temporarily from your seriation. The alternative is to delete the artifact in which case all information and data related to the artifact will be lost to this seriation permanently. In contrast, using Exclude allows you to resurrect the artifact and its data by clearing the Exclude field. All Exclude fields can be cleared simultaneously by selecting Artifacts | Include All from the OptiPath main menu.
Index - an integer value assigned to an artifact that allows you to sort artifacts in a list.
Artifact - a name that uniquely identifies the artifact. Artifact names are restricted to 50 characters. The artifact name is required for each artifact. An artifact cannot have the same name as another artifact and cannot have the same name as an assemblage. The following names are reserved for use by OptiPath and cannot be used as artifact names: Earlier, Later, OPS Index, OPS R Squared.
Assemblage - each individual artifact can be assigned to an assemblage. This allows you to enter data for individual artifacts but have OptiPath seriate collections, or assemblages, of artifacts. Assemblages can only be assigned by selecting an assemblage from a list. To do this, you must first create assemblages. The assemblages you create will be available for assignment to artifacts. To have OptiPath seriate assemblages rather than artifacts, you must set the Assemblages parameter for the seriation. The easiest way to do this is to select Artifacts | Use Assemblages from the OptiPath main menu or by clicking the Assemblages button
Description - an optional description that can be entered for each artifact. There is no limit to the length of a description.
Earliest - an integer value representing the earliest possible date that can be assigned to this artifact. The Earliest date should not be less than the overall Earliest date for the seriation which is set in the Seriations table. If you use an earliest date other than earliest date for the overall seriation, OptiPath will use a different objective function and a different algorithm to solve the seriation and computation times will be noticeably longer - see Optimal Path Seriation.
Latest - an integer value representing the latest possible date that can be assigned to this artifact. The Latest date should not be greater than the overall Latest date for the seriation which is set in the Seriations table. If you use a latest date other than latest date for the overall seriation, OptiPath will use a different objective function and a different algorithm to solve the seriation and computation times will be noticeably longer - see Optimal Path Seriation.
If you elect to show results by choosing Artifacts | Show Results from the Artifacts menu,
then you will see two additional columns, Order and Date, giving information about the current seriation:
Order - this parameter indicates an artifact's sequential (ordinal) position in a seriation. This field cannot be modified by the user. However, you can reverse the order of the seriation by choosing Seriate | Reverse from the OptiPath main menu or by clicking the Reverse button
on the toolbar.
Date - this parameter indicates an artifact's date as estimated by OptiPath in performing a seriation. Dates are are always given as an integer intending to represent a year. Although OptiPath calculates precise dates it rounds them to the nearest year. Users who need greater precision can refer to the Distance field in the Results window which is used by OptiPath to calculate the date. This field cannot be modified by the user.
This information can also be seen in the Results table.
If you elect to show data by choosing Artifacts | Show Data from the Artifacts menu, then you will also see columns for the data for each of your features.
Features - there is a separate column for each feature. Feature names cannot be edited in this table. Each cell in a feature column reflects the value of the measure for that feature for artifact in the corresponding row. Values can be numbers or letters or words, depending upon the feature data type.
You can enter and edit your data in this table or you can edit them in the Data table or in the Results table.
