15

Selecting Features

Select Set operations are used to specify which map object(s) you want to use as input to another GeoMedia command or which object’s attributes you wish to review or edit. When a single feature is a select set member, its associated attribute values can be viewed from Select Set Properties. Assume, for example, that you are viewing a map of a platted subdivision. Associated with each lot in the plat is information about the lot’s owner, address, valuation, and so on. Clicking on any lot in the map pops up a display of the attribute data for that lot. The lot, by virtue of its membership in a select set, is also a candidate for editing or deletion, and can be moved as well. A select set can alternatively be a group of map objects that have been chosen for simultaneous manipulation with the placement and editing commands.
 
 

Content and Characteristics
of Select Sets

Defining Select Set membership is a matter of clicking on features in the map window with the Select tool. In order for features in a feature class to be candidates for selection, they must be locatable. The Northwest arrow in a legend entry indicates that the feature class is locatable. You turn locatability on in the Locatable column on the Entries tab of the Legend Properties dialog (see Part IV for more information on managing the legend). Clicking in the cell toggles locatability on and off.

3 TIP: Turning locatability off for the legend entries you want to view but do not need to manipulate makes your workflows more efficient. When you have several densely clustered feature classes but are working with just one feature class, you can substantially reduce the number of times you will have to identify map objects with the Pick Quick dialog by turning locatability on for only those feature classes of interest. Similarly, in most cases there is no need for map objects such as images, logos, or thematics to be locatable. You can have only one select set active in a GeoWorkspace at a time. The same select set is visible in all displayed map windows. If a data window containing the same feature class is open, the records for members of the select set will be highlighted in the data window. However, the map window almost always drives select set membership. A select set can contain features from one or more source warehouses. A select set can also contain both read-only and read/write features. Naturally, features in read-only warehouses cannot be edited, moved, or deleted. You can tell that a feature class belongs to a read-only connection when you run one of the editing commands. Handles will not appear on any map objects to which you do not have write access. In addition, you are warned that the feature is read-only. Before going further, there are some concepts and terminology you need to become familiar with. These are covered in the sections that follow.

The Selection Toolbar

The Selection toolbar is one of the toolbars delivered with GeoMedia. It contains three buttons that allow you to access the Select tool and to select which fence mode you want to use. The Select tool is the Northwest arrow cursor, the button on the left in the illustration at left.

The Select tool plays an important role in navigating around the GeoMedia application. It is used to activate commands associated with icons, to select menus and items within the menus, and to move through dialog fields. It is also used to cancel the effects of other commands. For example, clicking on the Select tool turns off panning or zooming in the map window. It is used to select records from the data window. It is additionally used to identify and select objects in the map window.

The Select tool is the default active mode. It is accessible regardless of whether a map or data window is active. The remaining two buttons are the spatial operators for fencing operations. They specify how map objects are handled by fences. The Inside Fence button, the center button on the toolbar, tells GeoMedia to use only objects that fall entirely within a fence. The Overlap Fence button, on the right, allows inclusion of map objects within and touching a fence. These buttons are mutually exclusive. Activating one deactivates the other. They are accessible only when a map window is active.

2 NOTE: These commands do not appear on the Main Menu bar. They are accessible from the toolbar only. The Select Tool and the Locate Zone

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When Select mode is active, the Select tool button is depressed, and the tip of the cursor has a circle around it called the Locate Zone. When any part of a map feature falls within the Locate Zone, the object becomes a candidate for selection. The Locate Zone determines how close to a feature the cursor must be to highlight or select it. The size of the Locate Zone is set on the SmartLocate tab of the Tools > Options dialog, shown in the illustration at left.

Often, more than one feature will fall in the Locate Zone. This might happen when your graphics are very closely clustered, or when the Locate Zone is large. When multiple map objects are found in the Locate Zone, SmartLocate launches the PickQuick dialog to help you identify the object of interest from the group of objects in the zone. SmartLocate and PickQuick are discussed in material to follow.

An object within the Locate Zone of the cursor is not located or highlighted until the cursor has been paused over the object for a short time. The duration of the pause interval is also set on the SmartLocate tab. In the following workflow exercise you will practice using the Select tool and selection sets.

Workflow 15-1:

Using the Select Tool and Selection Sets

The Select tool has many uses in both the map and the data windows. The Select tool can be used to "point and click" to select a map object and review any attached attribute data. The Select tool can be used to select a map object as input to a move, edit, or delete operation. The map objects can be, in general, individual features, feature classes, images, or labels, although some of the operational functionality associated with these map objects are limited to single instances of a feature class.

Map objects can be selected individually, by legend entry, by fence, or by SmartLocate. They need not reside in the same warehouse, although functionality is more restricted when a connection is made to a read-only warehouse. You will be introduced to select set properties in this workflow. They are discussed in detail later in the chapter.

Open a new GeoWorkspace and create a read/write connection to the shapeland.mdb warehouse. Add all shape land features to the legend.

2 NOTE: The Selection toolbar consists of three icons. The arrow is the Select tool. In addition to being a selection tool, it is the main way to disable any functionality you have associated with the mouse cursor. For example, clicking on the Select tool turns off zoom or pan in the map view. The other two icons are the Inside Fence and the Overlap Fence icons. 1. Access Select tool functionality from the Selection toolbar. Click on the Select tool icon, the Northwest arrow on the Selection toolbar. The Select tool is only available from the toolbar. There is no access to Select or fence operations from the Main Menu bar. 2 NOTE: When the Select tool is active, the cursor is changed to an arrow and a Locate Zone indicator. As the cursor is moved in the map window, map objects within the Locate Zone are highlighted. Clicking on a highlighted object adds it to the select set and changes its display color to that specified as the select color.

Double clicking on a highlighted map object brings up the attribute data for that object. In this context, attribute records for the map objects can be viewed one map object at a time only.

2. Select a map object. Using the Selection tool, double click on any map object. This type of Select operation pertains only to individual map objects. You cannot review select sets consisting of multiple objects.

The General tab, shown in the first of the following illustrations, contains metadata for the map object. The attribute information for the map object is now available for review and/or editing. Editing attribute data will be covered later in this section. The Attributes tab of the Select Set Properties display is shown in the second of the following illustrations.

ig200004
 
 

Select Set Functionality

You have noticed that as you pass the cursor over features in the map window they change color. This is the highlight feature of the selection process. It shows you which feature or features are within the cursor Locate Zone. When you want to either view or edit the attribute values for a particular feature, or want to change the geometry of one feature or a group of features simultaneously, you must visually identify them, then select them for inclusion in a select set.

Select set functionality works in one of two ways. It allows you to interactively identify a single map object in the map window for the purpose of reviewing or editing its attribute values or select set properties. It also allows you to identify a single feature or groups of features you intend to use as input to the graphics Placement and Editing commands that operate on preselected objects. It is important to recognize this distinction from the start. The options available in Select Set operations are a function of the number of objects in a select set. When a select set contains more than one feature, Select Set properties are not available.

There is a lot of new terminology associated with Select Set operations. This chapter explores select sets, the Select Tool, SmartLocate, and the Locate Zone. The selection process probably has more ties to the parameters defined in the Options dialog than any other GeoMedia function.

The display characteristics of select sets, highlighting, and selection colors are defined on the Map Display tab of the Tools > Options dialog. The behavior of the Locate Zone and the pause interval are defined on the SmartLocate tab of the Options dialog. The units of measurement for area and line geometries displayed on the General tab of the Select Set Properties dialog are set up on the Units and Formats tab of the Options dialog.

Select sets are identified with the tools on the Selection toolbar, and are manipulated with the tools on the Placement and Editing toolbar. Placement and editing options are briefly reviewed here, and are covered in detail in Parts VII and VIII. This chapter reviews setting Select Set options and the various ways a select set can be constructed. The chapter then puts these parts together.

Workflow 15-2:

Setting Up Select Set Display Options

In this workflow exercise you will customize your map display options in order to facilitate the Select Set operations in subsequent exercises. Open a new GeoWorkspace. You do not need a warehouse connection for now.

1. Set the Select Set display options. On the Main Menu bar, click on Tools > Options. Click on the Map Display tab in the Options dialog, shown in the following illustration. ig200001

Replace illustration with hgm15_2

Adjusting the Map Display options makes visually identifying map objects for Select Set membership easier. 2. Change the Select Set display option. Click on Select and select a new color for the Select Set display. When map objects are added to a select set, they will display in this color. 3. Change the Select Set highlight color. Click on Highlight and select a new highlight color. When the Select tool is passed over map objects, they will display in this color. 4. Change the Select Set handle color. Click on Handles and select a new color for the Select Set display. The color for Handles is activated when map objects in a select set are going to be edited, deleted, or moved. 5. Change the map window background color. Click on Background and select a new color for the map window display. Click on OK to make these changes to the map window. 2 NOTE: Click on the Select tool icon to review the result of your changes to the map display. As you pass the cursor over various map objects, they change to the color specified as the highlight color. Clicking on a highlighted object adds it to the select set and changes its display color to that specified as the select color.

When you click on the Select tool button, the mouse cursor changes to an arrow with a Locate Zone indicator at the end. As you move the mouse cursor, any map object the Locate Zone passes over appears in the highlight color. When a map object is highlighted, you can click to select it. The size of the Locate Zone is set using Tools > Options > SmartLocate, and the highlight color is set using Tools > Options > Map Display.

When you select one or more features, they become a select set. You create a select set to edit it. When the select set contains more than one object, any Edit tool you select affects all objects in the select set simultaneously.

A select set can also contain both read-only and read/write features. Objects in the select set are distinguished as read-only or read/write by the display of handles in the map window when an Edit tool is selected. For example, if you select the Move tool when a select set is active, handles appear on read/ write objects but not on the read-only objects in the select set.

Interactive Selection

Before you can select a feature, you must identify it using the Select tool. A feature can be located only if it is displayed in the active map window and its locatability property is turned on. You select features by clicking on the left mouse button or by drawing a fence on the map when the Select tool is active.

When you pass the Select tool over a feature and pause for a short time, the map object changes to the highlight color. When you click on a highlighted object, its display changes to the selection color. Applicable editing buttons for the map object are enabled on the Placement and Editing toolbar, shown in the following illustration.

ig200006

2 NOTE: You can change the highlight and selection colors using Tools > Options > Map Display. Selecting a Single Feature

You select a single feature with a left mouse click when the Select tool is active. The feature is highlighted as long as any part of it is within the Locate Zone of the Select tool. The feature changes to the select color when you click on it. You simply activate the map window that contains the map object you want to select, click on the Select tool button on the Selection toolbar, and click on an object in the map window.

Reviewing Select Set Properties

Select set properties are only available when an individual map object belongs to the select set. Select set properties are available for feature classes, queries, thematics, and imagery. Properties for queries and thematics are those of the underlying feature class. The Properties display consists of two tabs: General and Attribute.

The General tab includes metadata about the feature class, including feature class name, connection name, and geometry type. The fact that the connection name appears here is important to keep in mind, especially when your legend contains feature classes from different warehouses that have the same feature name. The only other dialog that displays the connection name for a feature class is the Entries tab of the Legend Properties dialog.

For polygon and line features, the area or linear dimensions of the object are displayed. The dimensions are expressed in the units defined on the Units and Formats tab of the Tools > Options dialog.

2 NOTE: Dimension information is available on the General tab of the Select Set Propoerties display and can also be accessed through the Analyze Geometry command and with SQL. The Attribute tab contains the attribute values for the feature. If the data warehouse has a read/write connection to GeoMedia, the information on this tab is editable. When the connection is read-only, you can only review the attribute values.

Properties can be viewed for images and features. However, the types of data available and the content of the General tab are quite a bit different for the two. This tab contains the image name, type, format, file system location, and image connection name, among other things. Although the entries in the Values column can be highlighted, they cannot be edited. The Attribute tab is dimmed for imagery because there is no attribute data available. The General tab of the Raster Properties display is shown in the illustration at left.

To review select set properties, activate the map window, select a feature or image, and click on Edit > Select Set Properties on the Main Menu bar. In addition to using the menu, you can double click on the object, which selects it and immediately runs the Properties dialog. You can also select the feature and click on the Select Set Properties button. There is one on the Placement and Editing toolbar, and on the Legend toolbar. A third way to access this dialog is to right click in the map window and click on Select Set Properties on the pop-up menu.

Editing Select Set Properties

Editing properties pertains only to the attribute values of features, queries, and thematics in read/write connections. When queries or thematics are edited, the changes are actually made to the attributes of the feature class on which they are based. You can tell whether the information on the Attribute tab is editable; that is, in a read/write connection, by the background color of the list box. When the tab is gray, the values cannot be changed. When the background is white, the fields can be modified. The values displayed on the General tab cannot be edited, nor can the properties of imagery.

If the warehouse is Access and if the value you are changing is associated with a display parameter, the display will dynamically update. Suppose, for example, you have a world map of population with two classes. The first is 0 through 100,000,000, and the second is 100,000,001 or larger. If you edit the population attribute for a country’s population that was, for instance, 90,000,000 and change it to 110,000,000, the display of the county will change from that of the lower thematic class to the higher one.

For other warehouses, you will need to select Warehouse > Update with Warehouse Changes command to see the changes. In the following workflow exercise, you will practice viewing and editing selected object attributes. Working with attributes in GeoMedia Pro is covered in Chapter 31.

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Workflow 15-3:

Viewing and Editing Selected Object Attributes

Once you have an individual map object "selected," it is possible to not only review the attribute data for the object but to edit that data. Run GeoMedia and open a new GeoWorkspace. Connect to the shapeland.mdb warehouse and add all of its feature classes to the legend.

1. Make a feature a member of the select set. Click on the Select tool icon and select any feature in the map window. There can be only one member in a select set if you want to view properties. 2. Review the Select Set properties. Click on Edit > Select Set Properties. Alternatively, you can right click the mouse and access Select Set Properties from the pop-up menu. 3. Review the general properties. Click on the General tab. 2 NOTE: The General tab of select set properties contains some interesting information. Note that this display gives you not only the feature class or query set name but the connection name, connection filter, geometry type, and description. In addition, it provides a measurement of the feature geometry for area and linear type geometries. The units of measurement can be changed through Tools > Options > Units and Formats. 4. Review the attribute values. Click on the Attributes tab.

5. Edit the attribute properties. Click in the Value field for any attribute and type in the new attribute value. When you finish making changes, click on OK.

 Exercise caution with regard to what you change here. System attributes such as MGE mslinks and mapids are editable in this dialog. This will impact the integrity of your database. 2 NOTE: Attribute data can also be edited directly in a data window. See Chapter 9.
 
  Selecting Single or Multiple Features
from the Data Window

The link between the graphic display and its attribute values can be used to create select sets. Using the data window to create select sets is a type of hybrid in that it can be used to create single feature sets or multiple feature sets consisting of several or all of the feature instances in the class. This approach requires that both a map window and a data window be open for the target feature class. However, when select set creation is driven from the data window, the feature class need not be locatable.

This means of creating select sets comes in handy when you know something about the attributes of a feature but are unsure of which map object represents it. Say you know the FIPS code of the county in which you are interested but do not know which county it is in the map. Selecting the record in the data window by clicking on its leftmost button automatically makes the associated graphic a member of a select set. It is displayed in the map window in the Selection color and, depending on how your Map Window Properties are set up, the map window will either zoom in on the selected object or center itself on the object (see Chapter 8 for more information on Map Window Properties).

To select multiple adjacent records, click on the button on the far left of the first record; then, while holding down the Shift key, click on the last record in the range. To select multiple nonadjacent records, depress the Control key while you are selecting records. To select all records in the table, click on the button positioned left of the column headings.

3 TIP: An important point to bear in mind when working between data and the map window is that clicking in the map window always clears the select set. When moving from the data window to the map window, always use the Title bar of the map window to shift the focus and make the map window active.

 Selecting Multiple Features

There are only two reasons for selecting multiple map objects either by legend entry or in the map window. The first is to identify them as input to a Placement and Editing operation. This is a convenient tool for mass update of geometries. You can move or delete the entire select set, or, in the case of labels or points, rotate it.

The second use for multiple feature select sets is map window display control. When you have an active select set, the Fit Select Set button (shown in the illustration at left) is enabled on the Standard toolbar. This fits the extent of the select set to the map window, giving you a greater degree of control over feature display than you can get by trying to zoom in or out of a particular area. Selecting Features Using PickQuick

The PickQuick dialog is available whenever GeoMedia detects multiple features within the cursor Locate Zone. Multiple features may be inside the Locate Zone by virtue of graphics density, or they may be hidden or overlapped by other features in the map window as a result of their display priority.

When you pause the Select tool, an ellipsis may appear at the lower right of the Select tool. This indicates that SmartLocate has identified the presence of multiple features within the Locate Zone. SmartLocate can identify a maximum of ten map objects simultaneously. When you left click when the ellipsis is displayed, the PickQuick dialog (shown in the illustration at left) appears. The dialog contains a numbered button for each selectable feature in the Locate Zone. PickQuick can display a maximum of six buttons at a time. Therefore, if SmartLocate has found seven to ten features, the forward and reverse buttons appear on the dialog to give you access to the remaining features.

Moving the Select tool over each button without clicking causes the corresponding feature to be highlighted in the map window. The 4.0 release of GeoMedia contains a handy enhancement to PickQuick. As the cursor hovers over each button the feature class name is displayed as a tooltip. Additionally, if you have turned on ‘Add connection prefix to feature names’ on the General tab of the Tools > Options dialog, the tooltip will be formatted connection_name.feature_class_name. When the feature you want to select is highlighted, use the left mouse button and select its number on the PickQuick box. This adds it to the select set.

If you select a single feature with PickQuick, to view the Properties dialog you use must use the Edit > Select Set Properties command or the Select Set Properties button on either the Placement and Editing toolbar or on the Legend toolbar. Contrast this with double clicking on a feature, which immediately displays the Select Set Properties dialog.

Using PickQuick, you can add multiple objects to a select set in the manner previously described. Simply hold down the Shift or Control key while making your feature selection from PickQuick.

The appearance and behavior of PickQuick can be a bit confusing at times. This is because its behavior is a function of Locate Zone size in relation to map window display scale. Locate Zone size, as defined on the SmartLocate tab of the Options dialog, is a relative setting from large to small. You will notice that the size of the displayed Locate Zone does not vary with map window scale.

3 TIP: The area within the circle at the tip of the cursor is not an accurate representation of the true size of the Locate Zone. Say, for example, you have two very different sized feature classes in the map window: the States class from the US Sample Data warehouse and one county’s worth of Census tracts. When the two feature classes are fit to the map window, they display at a scale of approximately 1:25,000,000. The Locate Zone is medium size, but it is medium size at the scale of 1:25,000,000. In fact, the Locate Zone is now somewhere in excess of 1,000 miles square. When the Select tool is paused over the tract features, the Locate Zone technically includes not only all the tracts but the four surrounding state boundaries. (In reality, SmartLocate will only find the first ten features.)

Confusion arises when you are zoomed in to the display at a scale of 1:10,000,000. The tract features are now visually more distinct, but the size of the Locate Zone has not changed. When you move the Select tool around the map window, the tract features will not individually highlight. As you move to increasingly larger scales, it may become impossible to locate anything but small-scale features. This issue is easily resolved by deleting the States layer from the legend. In the workflow exercise that follows, you will practice using the Locate Zone and PickQuick.

Workflow 15-4:

Using the Locate Zone and PickQuick

In this exercise you will learn how to set up your Locate Zone with SmartLocate options. You will use PickQuick to identify map objects and to retrieve their attribute information. This type of selection functionality (PickQuick and Select Set Properties) is limited to single instances of a feature class in either read-only or read/write warehouses.

To begin, open a new GeoWorkspace. Connect read/write to the shapeland.mdb warehouse. Make sure you have all feature classes added to the legend. SmartLocate, in association with PickQuick, helps you to manage "dense" map graphics when developing selection sets. They are tools that help you isolate the relevant map objects from the others in the map window in cases where graphic elements are very close to one another or "stacked" on top of one another. The map window must be active for this type of select set operation to be possible.

    1. Set up SmartLocate options. On the Main Menu bar, click on Tools > Options. Click on the SmartLocate tab, shown in the illustration at left.
Replace illustration with hgm15_1

2 NOTE: SmartLocate allows you to specify the size of the Locate Zone at the end of the Select tool. Map objects that fall within the Locate Zone as the cursor is moved in the map window are highlighted and are available condidates for selection set membership.

 2. Size the Locate Zone. Drag the tab on the slider bar to change the size of the zone. Change the zone to its maximum size. Click on OK.

The size or tolerance of the Locate Zone is expressed internally in screen pixels. The new Locate Zone size is displayed in the Preview box. The best size for a Locate Zone is a function of the type, density, and scale of the geometry in the map window.

3. Set the cursor highlight delay. Slide the tab on the Scale bar to Short.

4. Turn on automatic panning at map boundary. Toggle panning on by clicking in the box to the left of the text "Pan map windows automatically." Click on OK.

 Automatic panning allows the map window to "scroll" when you reach the boundary of the display zone. 5. Check the SmartLocate function. Move the Select tool around in the map window. Notice that map objects are highlighted when the Select tool rests on them. Move around the window until you see multiple geometries within the Locate Zone. Three ellipses appear behind the Select tool indicating that more than one map object is within the Locate Zone. Both the Select tool and the map window must be active. 6. Activate PickQuick, When you have located a zone with multiple map objects in it, left click on the mouse. The PickQuick dialog is shown in the illustration at left. One number appears in PickQuick for each map object found within the Locate Zone. 7. Identify PickQuick map objects. When the cursor is moved to an object in the PickQuick box, the feature associated with the number displays in the highlight color in the map window. Select an object and click on its number. When there are more than six features in the Locate Zone, you can view them with the advance and reverse arrows. 8. View the selected object’s attribute data. On the Main Menu bar, click on Edit > Select Set Properties. Select set properties can also be accessed via the Select Set Properties button (shown in the illustration at left) on the Edit Geometry toolbar. You can also access Select Set Properties by right clicking the mouse in the map window to pop up the Edit menu. 9. Clear the select set. On the Main Menu bar, click on Edit > Unselect All. Clicking in the map window will clear the select set, as will activating almost any other command.
 
 

Selecting All Features in a Feature Class

To select all features in a feature class, highlight the feature class entry on the legend and click on Edit > Select by Legend Entry on the Main Menu bar. The display for the selected legend entry must be turned on, but the entry is not required to be locatable. This is the only exception to the rule requiring map objects to be locatable in the map window in order to qualify for selection. All map objects associated with the highlighted legend entry are selected. Using this option along with the Fit Selected zoom button is a good way to fill the map window with all features in a class.

Selecting All Features in a Query

Using the Select by Legend Entry command, you can create a select set from the results of a query. Create the query, add it to the legend, highlight it, and click on Edit > Select by Legend Entry.

Selecting Multiple Features Without a Fence

Multiple features are placed in a select set in one of two ways. When the target objects are geographically dispersed, they can be selected by clicking on them while keeping the Shift or the Control key depressed. Just activate the map window containing the features you want to select, click on the Select tool button, and select the first object. Then, while holding the Shift or the Control key down, select the next object.

Selecting Multiple Features with a Fence

When the map objects in which you are interested are located in a region that can be identified with a "box," you can use a fence to select them. To select the map objects using a fence, you must activate the map window in which you want to place the fence and select a fence mode. Fence modes, previously discussed, are Inside Fence and Overlap Fence and are located on the Selection toolbar. Press and hold the left mouse button on the first corner of the fence. Drag the mouse cursor to the opposite diagonal corner of the fence, and then release the mouse button.

When a fence operation appears to fail, confirm that the legend entry for the feature class is locatable. You cannot fence features that are not locatable, but you are given no warning to this effect. If the feature class is not locatable, there will not be a northwest arrow by the feature class entry in the legend. To make the feature locatable, double click on the feature entry in the legend box and change the status to locatable by clicking in the Locatable cell for that feature in the Legend Properties dialog. In the following workflow exercise, you will build select sets from multiple map objects.

Workflow 15-5:

Building Select Sets from Multiple Map Objects

In this exercise you will learn how to build select sets consisting of various types and combinations of map objects. Although Select Set Properties operates only on individual map objects, the select tools allow you to identify map objects as members of a select set that will become the input to another GeoMedia operation such as moving, deleting, or editing geometry.

Select set members can be, in general, individual features, features classes, images, or labels. Map objects can be selected individually or by SmartLocate PickQuick. They can also be selected on the basis of membership in a legend entry or location in or touching a fence.

Selected legend entries, fenced features, and individual features can be combined to form select sets using the Shift or Control key while selecting. They need not reside in the same warehouse, but because most select set functionality in this context refers to data manipulation, warehouses (normally) must be read/write. Feature classes must be locatable in order to be selected. To begin this exercise, open a new GeoWorkspace. Connect to the shapeland.mdb warehouse and add all of its feature classes to the legend.

1. Create select sets from multiple map objects. Click on the Select tool icon. Click on several features in the map window while holding down either the Shift or the Control key. Each map object is added to the select set. 2. Remove an object from a select set. Hold down either the Shift or the Control key with the Select tool active and left click on an already selected feature to be removed from the select set. The Shift and Control keys cause the Select tool to act basically like a toggle. If a feature that has been selected is clicked on, it is deselected. When an unselected graphic is clicked on, it is added to the select set. 3. Clear the select set. Left click anywhere in the map window. Executing most other Main Menu or toolbar commands will clear the select set, as will Edit > Unselect All. 4. Create a select set from a legend entry. In the legend, click on a feature class entry. On the Main Menu bar, click on Edit > Select by Legend Entry. Click in the map window to clear the select set. 5. Create a select set from multiple legend entries. In the legend, click on any feature class entry. Use the Shift key to select adjacent legend entries, or the Control key to select nonadjacent entries. On the Main Menu bar, click on Edit > Select by Legend Entry.

6. Create a select set with a fence and select the fence definition. Features to be selected by fence can either be entirely within a fence or can overlap the fence and qualify for selection. The only way to access these options is from the Select toolbar. There are no drop-down menu options for fences.

 Left click and drag the mouse to define the fence area. The features are automatically selected according to the fence definition. 7. Create a select set from combinations of individual features, fenced features, and/or legend entries. Fenced features, legend entries, and individual features can be added to a select set by simply holding down the Shift or Control key after the initial selection and addition of features.

8. Fit the select set to the map window. Click on the Fit Select Set icon, shown in the illustration at left.

 You can also click on View > Fit Select Set on the Main Menu bar.
 
 

Removing Individual Objects
from a Select Set

You can remove individual map objects from a select set the same way they are added. Click on the Select tool, and then while holding the Shift or Control key click on the objects you want to eliminate from the set.

Clearing a Select Set

Select sets are very transitory things. They are cleared by almost any other action taken in the map window, with the exception of the Placement and Editing commands. A select set is cleared automatically when another feature is selected without using the Shift or Control key. The select set is cleared when you click in any empty space in the map window. It is also cleared when you turn the display off or delete a legend entry.

When you are working in the data window, selecting New Record or Column will clear the set. You can explicitly clear the select set by clicking on Edit > Unselect All on the Main Menu bar. Additionally, executing almost any other GeoMedia command will clear the select set. Editing Feature Geometry

After a select set is created using any of the procedures previously described, the geometries can be modified. When a select set is moved, the features that make up the set act as if they are "grouped." Editing tools include Move, Delete, and Rotate, among others. You may wish to delete the geometry of selected feature or you may want to delete the entire feature. These are two different operations and are described below. All editing tools available act on all members of the select set simultaneously. The following sections review procedures for moving and deleting geometry. Placing and editing geometry is covered in detail in Chapters 26 and 30.

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Moving Features

When you move members of a select set, they retain their spatial relationship to one another and are relocated as a group. To move a select set, activate the map window and click on Edit > Move on the Main Menu bar. You can alternatively use the Move Geometry button (shown in the illustration at left) on the Placement and Editing toolbar.

Handles are displayed on all elements of the select set to indicate that they can be moved. Click on a select set handle to attach it to the cursor, or click in the map window and drag the select set to the new location.

Deleting Feature Geometry

You can delete a select set by clicking on Edit > Delete Geometry on the Main Menu bar, or by using the Delete Geometry button (shown in the illustration at left) on the Placement and Editing toolbar. In the following workflow, you will practice moving and deleting select set geometry.

Workflow 15-6:

Moving and Deleting Select Set Geometry

Select sets can be used as input graphic editing routines to make mass changes to warehouse geometry. Select sets consisting of multiple map objects, in this context, behave much as "grouped" objects in Microsoft Office products. The Select set is moved or deleted as if it were a single map object. The workflows in Parts VII and VIII go into detail regarding other aspects of feature development and editing in GeoMedia and GeoMedia Pro.

In this exercise you will review steps for moving and deleting select set graphics. Open a new Geo Workspace and create a read/write connection to the shape land.mdb warehouse.

1. Build a single member select set. Point and click on any map object. Notice that the Placement and Editing toolbar is now enabled. 2. Move the object. Click on the Move icon. Click anywhere in the map window and move the mouse. A second click will place the graphic at the new location. The selected graphic is now attached to the mouse. To cancel this operation, click on the Select tool. 3. Build a multiple object select set by legend entry. Highlight one of your legend entries and on the Main Menu bar and click on Edit > Select by Legend Entry. The select set is displayed in the color set in Tools > Options > Map Display > Select. 4. Move a multiple object select set. Click on the Move icon, then in the map window. Now the entire select set is attached to the mouse and can be relocated. 5. Delete a multiple object select set from the map window. Holding down the Shift or Control key, click on several map objects. Click on the Delete icon, shown at left. You are asked to confirm the deletion. Remember that there is no Undo function in the GeoMedia map window, however there is Undo functionality in GeoMedia Pro.

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6. Delete a multiple-object select set from the data window. Open a new data window for one of the remaining feature classes. Select multiple attribute records by holding down the Shift or Control key and highlighting them. Click on the Delete button. The selected records are removed from the attribute table and the map window is updated. This is one instance where the Delete key on the keyboard is disabled.

Options That Apply to Select Sets

There are three tabs on the Tools > Options dialog that set defaults for Select Sets. The SmartLocate options control how the Select tool will work and parameters on the Map Display tab control the color symbology used to identify and select map objects. The Units and Formats tab contains settings that control the units of measure used in the display of feature area and length on the Properties dialog.

Setting SmartLocate Options

New figure hgm15_1

The SmartLocate Tab of the Options dialog.
 
 

The SmartLocate tab, shown in the illustration at left, is divided into three sections. The first two sections set variables that control the way map objects and the Select tool behave during select set operations. The third section allows you to specify whether you want autopanning to function and how you want it to work. All settings defined on the SmartLocate tab are stored in the system registry, and apply to all GeoWorkspaces.

When the Select tool (the arrow) passes over a graphic feature in an active map window, the feature is displayed in the Highlight color you assigned on the Map Display tab. The first selection on the SmartLocate tab is a slider bar that sets the length of delay between the time the Select tool passes over the object and the time it becomes highlighted.

In the second section, you can customize the size of the cursor locate zone. A feature is highlighted, and therefore available for selection, when it falls within the cursor locate zone. This zone is simply a circular area at the tip of the select tool that defines the range in which the cursor is able to identify map objects. The size or tolerance of the Locate Zone is expressed internally in screen pixels.

In many displays there are multiple features in close proximity to one another. For example, roads cross over streams, parcel boundaries are near water valves, and so on. All features that fall within the cursor locate zone are selectable. When more than one map object falls inside the locate zone, a dialog is launched that allows you to identify the object you are interested in from all objects that.

When the zone is very large, you will be locating many features. On the other hand, if it is too small, you may not be able to select a feature without a lot of detailed mouse movement. The size of the zone should be set based on the detail and complexity of your graphics. The locate zone size for both the Select tool and the Placement and Editing cursor (the crosshair cursor) is displayed in the preview box as you drag the slider bar button.

The last section on the SmartLocate tab is used to specify parameters for automatic panning in the map window. When autopan is turned on, it is functional for all open map windows, but operates in the active map window only. Autopan allows the map window to automatically pan when you approach the pan zone while measuring distance or placing, editing, or moving map objects.

The pan zone is expressed as a percentage of the map window, and ranges from 0 to 50 percent. When you reach a boundary of the pan zone while measuring or editing, the window scrolls to keep your cursor within the pan zone. The pan zone itself can optionally be displayed. However, it only appears when you are executing measuring or editing operations.

The sample box shows you approximately what proportion of the map window the specified pan zone will encompass. When you change the size of the pan zone, the sample window does not update until you click on OK, which dismisses the dialog box. The sample window will properly display on subsequent runs of the SmartLocate dialog.
 
 

Controlling Select Set Display

In the second panel of the Map Display tab you can change the colors used to display select sets, the handles used to graphically manipulate map objects, the highlight color that indicates which map object lies under the cursor, and the map window background color. See Workflow 15-2 above for details.

3 TIP: Be sure to consider how the background color and the select color will interact. If both the background color and select color are white, selections in the map window will "disappear." When you change these, be sure to use contrasting colors. With the exception of the background color, these are all display options that pertain to working with select sets. The defaults set in the Map Display dialog are GeoWorkspace specific.
 
 

Defining Units of Measure

New Figure hgm15_3

Caption The Units and Formats tab in the Options dialog

On the Units and Formats tab of the Options dialog you select the ground units for linear and polygon features. To set the unit of measure for linear features select Distance from the Type drop-down, then select the appropriate measurement from the Units drop-down and the number of decimal places from the Precision drop-down. Select Area for polygon measurements, then choose from the Units and Precision drop-down menus. The units you select on this tab are used as defaults by the Select Set Properties display, the Measurement tool, and the Analyze Geometry command. These parameters are stored in the GeoWorkspace and therefore apply only to the open workspace file. T