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Transform features using a Similarity transformation

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The Spatial Adjustment toolbar allows you to transform, rubbersheet, and edgematch your data within an edit session. Spatial adjustments are based on displacement links. These are special graphical elements that represent the source and destination locations for an adjustment.

If the Editor toolbar isn’t displayed in ArcMap, click the Editor Toolbar button on the Standard toolbar to add it. If the Spatial Adjustment toolbar isn't visible, click the View menu, point to Toolbars, and click Spatial Adjustment to add the Spatial Adjustment toolbar.

Before you start adding links, you should set your snapping environment so each link you add snaps to the vertices or endpoints of features. In this example you'll snap to the Vertices of NewParcels and SimpleParcels, so the displacement links will snap to the vertices of these features.

A transformation is used to convert the coordinates of a layer from one location to another. This involves the scaling, shifting, and rotation of features based on displacement links you define. Transformations are applied uniformly to all features in a feature class and are often used to convert data created in digitizer units into real-world units represented on a map.

This example shows how to apply a transformation that will move, scale, and rotate two feature classes containing parcel and building features into alignment with another set of parcel and building feature classes. You might use this technique to adjust data that was digitized or imported into a temporary feature class in preparation for copying and pasting the features into your database. You will also learn how to specify which features to adjust, preview the adjustment, and view a link table.

The Spatial Adjustment tool allows you to adjust a selected set of features or all the features in a layer. This setting is available in the Choose Input For Adjustment dialog box. The default is to adjust a selected set of features.

The next step is to choose an adjustment method. The Spatial Adjustment tool supports several adjustment methods. In this example you will see a Similarity Transformation.

Displacement links define the source and destination coordinates for an adjustment. Displacement links can be created manually or loaded from a link file. In this example, you will see how to create your own displacement links from the exterior corners of the NewParcels layer to the corresponding locations in the SimpleParcels layer.

You can preview the results of an adjustment prior to actually performing the adjustment. This tool is called the Preview Window. If the results are not adequate, you can modify the links to improve the accuracy of the adjustment.

In addition to the visual preview of the adjustment, you can also examine the results of the adjustment by viewing the Link Table. The Link Table provides information about link coordinates, link IDs, and Root Mean Square (RMS) errors.

Right-clicking a link record opens the Link Table’s context menu. You can edit link coordinates, flash links, zoom and pan to selected links, and delete links with these commands.

If the RMS error for this adjustment is not acceptable, you can modify the links to increase the accuracy. The Preview Window and Link Table tools are designed to help you fine-tune your adjustment.

The final step of the spatial adjustment process is to perform the adjustment. Since the Spatial Adjustment tool operates in an edit session, you can use the Undo command to undo the adjustment.

If you are satisfied with the results of the spatial adjustment, you can stop editing and save your edits.


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