Selecting Map Features

When you select features on a map, you can then view a report that provides information about the selected features, or you can adjust the map display to zoom to the selected features. The number and type of selected features are displayed on the status bar at the bottom of the map.

Note When you select a map feature, Autodesk MapGuide selects the feature by its key. Therefore, if you select a map feature that contains multiple points, each of which has the same key, each of those points will be selected. Similarly, if there are multiple features in the map with the same key, selecting one of those features will select all features that share that same key.

You can do any of the following to select features on a map:

Specifying the selection mode

Selecting features within other map features

Selecting features within a specified distance from other map features (View Buffers command)

Selecting map features by name

Selecting individual map features

Selecting all map features in a rectangular area

Selecting all map features in a circular area

Selecting all map features in a polygonal area

Deselecting map features

 
Specifying the Selection Mode

By default, when selecting features inside a rectangle, circle, polygon, or buffer, Autodesk MapGuide selects only those features whose centroids (center points) are within that selection area. However, you can specify that you also want to select features that intersect the selection area.

To specify the selection mode

1. Right-click in the map, and then choose Help > Preferences from the popup menu to display the Preferences dialog box.

   

2. Click the Selection Mode drop-down list, and then choose the method you want to use for selecting features inside of other features.

   If you choose Centroid (the default), only those features whose centroids are within the selection area will be selected. If you choose Intersection, features that touch, intersect, or are within the selection area will be selected.

 
Selecting Features Within Other Map Features

Autodesk MapGuide Viewer can select all map features that are within selected polygon map features. The polygons should be on their own layer in order for this command to work effectively.

To select features within other map features

1. Select the polygon map feature(s) containing the map features you want to select.
2. Right-click in the map, and then choose Select > Within from the popup menu to display the Select Within dialog box.

   

3. Choose the map layer containing the map features you want to select should they fall within the polygon(s) you selected in Step 1, and then click OK.

   For example, if you selected a buffer feature in step 1 that represents a specific distance from a customer's location, and you want to find all Acme Widget resellers within that specified distance from the customer's location, you would select the layer that contains the reseller locations.

   All map features from the specified layer that fall within the previously selected polygon(s) are now selected.

 
Selecting Features Within a Specified Distance from Other Map Features (View Buffers Command)

By creating a buffer around selected map features, you can view all features that fall within that buffer. This is particularly useful in site selection. For example, you could create a buffer to find all vacant lots within two miles of your stores, or using a report that will calculate area, you could determine the total area within the buffers around your stores.

To select features within a specified distance from other map features

1. Select the map features around which you want to create buffers.
2. Right-click in the map, and then choose View > Buffer from the popup menu.

   The View Buffer dialog box appears.

   

3. In the Buffer Offset Distance text box, type the distance you want the buffers to extend from the selected features, and then select the unit (such as miles or kilometers) you want to use from the drop-down list.

   For example, to find all features within two miles of your stores, type 2 in the text box and choose "mi" from the unit list. Note that you can also use the up and down arrows to increase or decrease the distance.

4. To treat all of the buffer areas as a single feature, instead of treating each buffer area as a separate feature, select the Construct One Buffer For All Selected Map Features check box.

   This is particularly useful if any of your buffers overlap and you do not want the overlapping area counted twice. For example, if you want to determine the total area around your stores, and two stores are close enough that their buffers overlap, you would not want to count the overlapping area twice. Overlapping buffers will also appear differently on the screen. For example, if you did not select this check box, overlapping buffers might display like this:

   

   If you did select this check box, however, the same buffers would display like this:

   

5. In the Create Buffer On list, select the map layer on which you want to create the buffers, or type a new name to create a new map layer that contains only the buffers.
6. In the Fill area, specify the style, color, and pattern to use for filling the buffer areas.
7. If you chose a hatch pattern for the fill, the color you specified is for the pattern, so you need to specify settings for the background behind the pattern. In this case, in the Background area, specify whether the background should be opaque (buffers cover the map features) or transparent (map features show through the buffers), and the color to use for the background.
8. In the Edge area, specify the style, color, and thickness to use for drawing the outer line around the buffer areas.
9. Click OK.

   Autodesk MapGuide creates the buffers around the selected features. To select the features within the buffers, you select the buffers, and then use the Select Within command to select map features from other layers that fall within the buffers.

   If you receive an error message about low memory while processing the buffers, see Improving Buffer Processing.

 
Selecting Map Features by Name

If you know the names of the map features you want to select, you can select them from a list.

To select map features by name

1. Right-click in the map, and then choose Select > Select Map Features from the popup menu to display the Select Map Features dialog box.

   

2. In the Map Layers list box, select the map layer that contains the map features you want to select.
3. In the Map Features list box, select the map features you want by doing one or more of the following:
   • Click a single map feature. For example, click Connecticut to select it.
   • Shift-click to select multiple contiguous features. For example, click Arizona, and then Shift-click California. Arizona, Arkansas, and California are all selected.
   • Ctrl-click to select multiple non-contiguous features. For example, after selecting Arizona through California, you could Ctrl-click Connecticut to add it to the selection without adding Colorado as well. You can also Ctrl-click to deselect individual features from the group of selected features.
   • Click All to select all features in the list.
   • Click Clear to deselect all features in the list.
4. When you finish selecting the map features you want, click OK.

 
Selecting Individual Map Features

You can easily select an individual map feature.

To select individual map features

Do one of the following:

• Turn on Selection mode by clicking the Select tool on the toolbar or by choosing Select > Select from the popup menu, and then click the feature. This selects the feature and deselects all previously selected features.
• While in Selection mode, Shift-click the feature. This adds the feature to the group of previously selected features.

 
Selecting All Map Features in a Rectangular Area

You can draw a rectangle to select all map features that fall within that rectangular area.

To select all map features in a rectangular area

1. Turn on Selection mode by clicking the Select tool on the toolbar or by choosing Select > Select from the popup menu.
2. Click the left mouse button, drag the mouse pointer diagonally until the rectangle covers the area you want, and then release the mouse button.

   All map features that are within the rectangular area are now selected.

 
Selecting All Map Features in a Circular Area

You can draw a circle to select all map features that fall within that circular area.

To select all map features in a circular area

1. Right-click in the map, and then choose Select > Radius from the popup menu.
2. Press and hold the left mouse button on a center point, drag to define the radius, and then release the mouse button.

   The radius appears dynamically on the status bar at the bottom of the map as you drag the pointer. When the pointer stops, the radius also appears as a MapTip.

   All map features that are within the circular area are now selected.

 
Selecting All Map Features in a Polygonal Area

You can draw a polygon to select all map features that fall within that polygonal area.

To select all map features in a polygonal area

1. Right-click in the map and choose Select > Polygon from the popup menu.
2. With the left mouse button, click each point that you want to use as a vertex of the polygon.
3. On the last vertex you want to use, double-click using the left mouse button.

   All map features that are within the polygonal area are now selected.

 
Deselecting Map Features

You can deselect map features after you have selected them.

To deselect one feature while leaving the other features selected

• Shift-click the feature you want to deselect.

To deselect all features

Do one of the following:

• Right-click in the map, and then choose Select > Clear from the popup menu.
• Press ESC. Note that this does not work if you are using the Java Edition of the Viewer on an Apple Macintosh computer.