Overview of snapping

Snapping is an automatic editing operation in which points or features within a specified distance or tolerance of other points or features are moved to match or coincide exactly with each other’s coordinates.

The Snapping page of the Table of Contents dialog box is used to specify which layers will be used to snap to when creating or editing features, and which part of the layer’s features will be snapped to. You can also specify whether or not the snapping buffers will be displayed, and the snapping tolerance for individual layers.

The snapping buffer can also be displayed by holding down the Ctrl key on PCs or the center button on Windows Mobile devices —when using this method the snapping buffer is only displayed while the key or button is held down. The snapping tolerance is used for the radius of the snapping buffer.

The snapping tolerance can also be set in the Snapping page of the Map Properties dialog box. The snapping tolerance set in the Map Properties dialog box is used for all layers in the map that do not have a snapping tolerance set in the Snapping page of the Table of Contents. The snapping tolerance units are the display units specified in the Display page of the ArcPad Options dialog box.

Snapping can be set for three parts of polylines and polygons: vertex, edge, or end. The end option is used for snapping to points. When the vertex, edge, or end are checked, points of the corresponding point shapefile or AXF layer and parts of the corresponding polyline or polygon shapefile or AXF layer will be used to snap to, using the snapping tolerance. When the Vertex option is checked, any existing vertex in the corresponding polyline or polygon layer will be used for snapping.

When the Edge option is checked, any part of the corresponding polyline or polygon layer will be used for snapping. When the End option is checked, only the start and end vertices of the corresponding polyline or polygon layer will be used for snapping, and the points of the corresponding point layer will be used for snapping.

The snapping environment can help you create points or vertices at more exact locations relative to other features. When you use the snapping environment in ArcPad, you must choose which part of the existing features—vertex, edge, or end point—you want your feature to snap to. These choices are called layer snapping properties.

In ArcPad, you can select to snap to an existing point, the vertex of a line or polygon, edge of a line or polygon, or the end point of a line.

Snapping properties are selected under the Snapping tab in the Table of Contents.

Tip:

Specifying the snapping tolerance for all layers in the map: The global snapping tolerance for all layers in the map is specified on the Snapping page of the Map Properties dialog box.

Tip:

Snapping shortcut key: To display the snapping buffers, tap the center button on a Windows Mobile device or the Ctrl key on a desktop PC. With this tool active, you are also forcing all pen actions for the following tools to also be snapped: Identify, Measure, and Advanced Select.