Assemblages
Assemblages are collections of artifacts. Archaeologists often deal with assemblages rather than individual artifacts. For example, an investigator might be concerned with finding a single date for a stratigraphy layer rather than trying to date the items within it individually. OptiPath can work with collections entered as individual items in the Artifacts table, where the feature data might be the fraction or percentage of artifacts in the collection that possess the feature, or it can build assemblages from individual artifact data. In this latter case, the artifact data could be 0's and 1's representing whether an artifact possesses a feature, and OptiPath would aggregate the data for all artifacts for an assemblage to get the assemblage data.
By choosing Assemblages in the seriation parameters
or by selecting Use Assemblages from the Assemblages menu
or the Artifacts menu, or by clicking the Assemblages button
on the toolbar,
you can direct OptiPath to classify individual artifacts by their assemblages
and then seriate the assemblages rather than the artifacts individually. The
implication is that frequency seriation will be
used to seriate the aggregated assemblage data; however, this is not required.
The Assemblages button is a toggle, being replaced by the Artifacts button
when you are using assemblages.
Assemblages Menu
Show/Hide Table allows you to open/close the assemblages table and create, delete, exclude and edit the assemblages and edit their parameters (but not their data).
Show/Hide Data is a toggle that specifies whether assemblage feature data is to be displayed in the assemblages table. This item toggles between Show Data and Hide Data. This menu item is disabled if not using assemblages or if the assemblages table is not open.
Show/Hide Results is a toggle that specifies whether seriation results are to be displayed in the assemblages table. This item toggles between Show Results and Hide Results. This menu item is disabled if not using assemblages or if the assemblages table is not open.
Include All allows you to include all excluded assemblages, and all their constituent artifacts, in the next seriation.
Sort -> Index allows you to reindex all included assemblages in the order they currently appear in the Assemblages table. This is useful for saving a particular seriation (sort the table by the Order column by clicking on the column header and then click Sort -> Index in the Assemblages menu). The Order Errors term in the Seriations table will then give an indication of how different a subsequent seriation is.
Sort -> Order allows you to reorder all included assemblages in the order they currently appear in the Assemblages table. This is useful for creating a seriation (sort the table by any column by clicking on the column header and then click Sort -> Order in the Assemblages menu). The Results will be updated to reflect the new seriation.
(Don't) Use Assemblages is a toggle that allows you to (not) use assemblages
in your seriation. Not using assemblages is equivalent to using artifacts.
This item toggles between Use Assemblages and Don't Use Assemblages.
There are corresponding Assemblages
and Artifacts
buttons on the toolbar. You will not be able to edit assemblages unless
you have chosen Use Assemblages.
Help will bring up this documentation.
Assemblages Table
In the Assemblages table you may add, delete, exclude and edit assemblages and their data. You will not be able to edit assemblages unless you have chosen Use Assemblages.
Right clicking on the table will bring up a pop up menu of available actions.
The rows of the Assemblages table may be sorted by the values of any column by clicking on the header for that column. Clicking a second time will reverse the order.
There are two rows with artifacts labeled EARLIER and LATER that are in green. These are virtual artifacts added by OptiPath to represent assemblages earlier and later than those in your data. The entries in these rows are read only and cannot be edited. However, the entries can be modified by editing the corresponding entries in the Seriations table.
If Use Assemblages and Show Results have been selected in the Assemblages menu, there will be a row in red that shows the unimodal index for the seriation and for each feature.
By choosing Hide Results and Hide Data in the Assemblages menu, you can reduce the number of fields displayed.
You can enter and edit assemblage parameters in this table but you cannot edit the feature data. Assemblage feature data is aggregated from feature data of the artifacts in the assemblage. There are a number of parameters associated with each assemblage:
Exclude this parameter allows you to exclude an assemblage temporarily from your seriation, or to exclude the assemblage's artifacts from the seriation. The alternative is to delete the assemblage in which case all information and data related to the assemblage will be lost to this seriation permanently. In contrast, using Exclude allows you to resurrect the assemblage and its artifacts and their data by clearing the Exclude field. Excluded assemblages cannot be edited.
Index is an integer value assigned to an assemblage that allows you to sort assemblages in tables.
Assemblage - a name that uniquely identifies the assemblage. Assemblage names are restricted to 50 characters. The assemblage name is required for each assemblage. An assemblage cannot have the same name as another assemblage and cannot have the same name as an artifact. The following names are reserved for use by OptiPath and cannot be used as assemblage names: Earlier, Later, Unimodal Index.
Description - an optional description that can be entered for each assemblage. There is no limit to the length of a description.
Earliest is an integer value representing the earliest possible date that can be assigned to this assemblage. The Earliest date should not be less than the overall Earliest date for the seriation which is set in the Seriations table. Assigning Earliest dates other than Earliest date for the overall seriation will generally result in longer computation times when seriating. Setting an Earliest date can result in a precedence relation being created (if the Earliest date is later than another assemblage's Latest date). Changing the value of Earliest for an assemblage will automatically cause Earliest for individual artifacts in the assemblage to have the same value for those artifacts that had the same Earliest date as the assemblage (artifacts in the assemblage with different Earliest date are assumed to have values overriding that for the assemblage).
Latest is an integer value representing the latest possible date that can be assigned to the assemblage. The Latest date should not be greater than the overall Latest date for the seriation which is set in the Seriations table. Assigning Latest dates other than Latest date for the overall seriation will generally result in longer computation times when seriating. Setting a Latest date can result in a precedence relation being created (if the Latest date is earlier than another assemblage's Earliest date). Changing the value of Latest for an assemblage will automatically cause Latest for individual artifacts in the assemblage to have the same value for those artifacts that had the same Latest date as the assemblage (artifacts in the assemblage with different Latest date are assumed to have a date overriding that for the assemblage).
Use Dates allows you to use or ignore the Earliest and Latest dates for this assemblage in seriating when Use Dates is checked on the Seriations table. Use Dates on the seriation tells the algorithm whether to use Earliest and Latest dates, and Use Dates on the assemblages tells the algorithms which dates to use, assemblage by assemblage. When Use Dates is not checked on the Seriations table, Use Dates tells OptiPath which dates to use when computing date Errors. If you right click on the Use Dates column a pop up window will appear allowing you to select or unselect Use Dates for all of the artifacts simultaneously. Ignoring Earliest and Latest dates for an assemblage will cause any relation that is a result of those dates to be excluded. Selecting Use Dates will cause those relations to be included. Changing the value of Use Dates for an assemblage will automatically cause Use Dates for individual artifacts in the assemblage to have the same value for those artifacts having the same Earliest and Latest dates as the assemblage (artifacts in the assemblage with different Earliest or Latest date are assumed to have dates overriding those for the assemblage and the artifact's value for Use Dates is likewise assumed to override that for the assemblage).
Order indicates an assemblage's sequential (ordinal) position in a
seriation, when using assemblages. This field cannot be modified by the user. However, you can reverse
the order of the seriation by choosing Reverse from the Seriate menu or the
Results menu or by clicking the Reverse button
on the
toolbar.
Date indicates an assemblage's date as estimated by OptiPath in performing a seriation, when using assemblages. This field cannot be modified by the user. This information can also be seen in the Results table.
Distance, when using assemblages, gives an assemblage's distance along the path computed by OptiPath in performing a seriation expressed as a fraction of the total distance of the path (the total path length is normalized to 1). This field cannot be modified by the user. This information can also be seen in the Results table.
Rate indicates an assemblage's rate of change from the previous assemblagein the seration as computed by OptiPath, when using assemblages. The rate of change is the difference in distances divided by the difference in dates. This field cannot be modified by the user. This information can also be seen in the Results table.
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 the assemblage in the corresponding row. Values cannot be edited in this table. Assemblage feature data is aggregated from feature data of the artifacts in the assemblage.
Warning! The following entries in feature data will be interpreted literally:
Present & Zero
Absent & Zero
Present & Unknown
Absent & Unknown
Unknown & Zero
Unknown
These six values (they are case sensitive) are the only allowed values for Earlier and Later, and Blanks and Zeroes. However, OptiPath will interpret them literally wherever they appear in the feature data.