The AMPR Map Collection Manager User’s Guide

Subsetting the Collection

Normally the collection viewer window, in its List view, displays all the records in your collection. However, if you wish to look at only a specific part of your collection – for example, all maps published before 1750 – you can choose to restrict the viewer to just display a subset of the full collection. The collection window and all its functions behave exactly the same when a subset is active as they do when the full collection is displayed; the only difference is that the only records shown are those which meet the criteria defined for the subset.

You can define multiple subsets. You give each subset a name, and, once defined, you can switch to any particular subset by choosing its name from the Subset menu. Subset definitions are saved as part of your collection, so the next time you run the program, any subsets that you defined previously are available to be selected from the Subset menu.

To define a new subset, or to modify or delete an existing subset, pick Manage Subsets from the Subset menu. The following dialog box will be displayed:

The dialog box shown above, mostly empty, is what you will see before any subsets have been defined. If any subsets have been defined for the collection, then the dialog will be filled in, reflecting the definition of one of the existing subsets. You can use the drop-down list to switch the display to show the definition of a different subset. Here is an example of what the dialog box looks like when one or more subsets have been defined:

To create a new subset, click on the “Create New Subset” button. This will bring up the following dialog box:

Provide a name for the new subset by typing a new name to replace “new subset”. Then specify the criteria that have to be met for a record to be included as part of the subset.

There are three kinds of criteria:

· Criteria for text fields (applies to short-text, long-text and image link fields) – A text field condition specifies whether the text field contains, or does not contain, the specified text. (Case does not matter; a lower-case word “chart” will match “Chart”, “CHART”, etc.)

· Criteria for number fields – A number condition specifies whether the field contains a value that is less than, equal to, or more than a specified value.

· Criteria for date fields – A date condition specifies whether the field contains a date that is before, in, or after a specifed date. (Dates can be single years, or fully specified dates, e.g., “25-Feb-2007”). The choice of “in” is intended primarily for specifying single years. For example, if you want to include in the subset all maps that you acquired in 2002, you could specify that the “Date acquired” field be “in” 2002. This will pick up all records with a 2002 year in the “Date acquired” field, regardless of whether they also include month and or day data.

Alternatively, a condition can specify whether a given field is empty or is not empty. This can be useful if you want to define a subset based on whether data is missing for a particular field.

To define a new condition:

1. Select a field name from the drop-down list at the upper left. You can also select the intially displayed choice of “Any text field” which will allow a text match against any of the text fields in your collection.
2. Select the desired relationship from the next drop-down list.
3. Enter the comparison value in the text-entry box at the right. (If you specified “is empty” or “is not empty” in the previous step, the text-entry box will be hidden, since it doesn’t apply in these cases.)
4. Click the “Add to Subset” button. The condition will be added to the list shown in the window.

If you have multiple conditions, they can be connected by “AND” or by “OR” operators. Adjacent AND conditions must all be met for a record to be selected for inclusion. An OR operator means that if the prior condition (or group of AND-connected conditions) is not satisfied, then the subsequent condition (or group of AND-connected conditions) will be tried. Following is an example of a filled-in dialog box showing two conditions connected with an AND operator:

This specification will cause the subset to include all 17^th-century maps.

To modify a line of the subset specification, select it in the list, edit the terms of the condition at the top, and then click the “Modify Line” button.

To remove a specific condition from the subset specification, click the condition in the list and click the “Remove from Subset” button.

Click the “Clear entire Subset” button to get rid of all the lines in the subset specification.

Selecting a subset

Use the Select a Subset sub-menu on the Subset menu to switch to using any of the subsets you have defined. When you click on Select a Subset a sub-menu will appear showing the names of all the available subsets. Click on the subset you want to select it.

To turn off subsetting, choose Show Full Collection (no subsetting) from the Subset menu. This will return the collection window to a display of all the records in your collection. No subset definitions will be lost by turning off subsetting; you can switch back to using a subset at any time by again selecting a subset from the menu.

Choose Display Subset Definition from the Subset menu to bring up a window showing you the criteria in effect due to the active subset. (If no subset is currently active, this will be reported.)

Notes on operating with a subset defined:

• When a subset is defined, the label at the top of the collection viewer window will indicate this, and will show how many items are in the subset out of how many items are in the entire collection.
• Operations that operate on the whole list (printing all records, exporting, searching and sorting) will only operate on the records that are included in the subset.
• When a subset is active and you add new records, a newly added record may or may not be in the subset, depending upon the value of its data fields. If the newly added record is excluded from the subset, you will not see the record appear in the List view window when you complete the data-entry operation. Because of this, you may think that the entered data has not gone into the collection; however, it will successfully be added to the collection (even if not to the current subset), and a warning message will be shown to remind you that newly added records might not be seen due to the use of a subset.

Examples of subsets

Here are some examples of subset definitions, that give an idea of how subsetting can be used.

Name	Conditions	Notes
17th century	'Date' GREATER THAN 1599 AND 'Date' LESS THAN 1700
Wish List	'Status' CONTAINS wanted	Uses a user-defined field (Status) to differentiate between ‘present’ & ‘wanted’ items.
Maps with images	'Image Link' IS NOT EMPTY
Maps acquired in 2006	'Date acquired' IN 2006	Using simply a year (no month or day) with the IN operator correctly matches any date in the specified year.
Texas Maps	'Region' CONTAINS Texas OR 'Title' CONTAINS Texas	Tries to also include maps where region might be broader (e.g. U.S. Southwest), but Texas is given significance as part of the map title.

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