|Easy Tip! Selecting objects within a radius and inverting (reversing) the selection|
|This tip is about analysing objects within a given radius of a particular location. It is also possible to work with the data that are outside of a given radius. This article will explore both techniques. This sort of analysis is commonly done with point objects but it can be done with lines or regions as well.|
This article makes use of the Radius Select and Invert Selection buttons. These are found on the Main toolbar
Selecting within a Radius
MapInfo Professional includes a handy Radius Select tool on the Main toolbar. Simply use this to click and drag and draw a circle. The tool will select everything inside the circle. Note that the Status bar indicates the radius as it is being drawn.
Left: As the Radius tool is used, the radius is displayed in the Status bar. Right: The selection has been made.
Once the selection is made, it can be viewed in a Browser, in the Statistics window, as its own layer in a map window and in general be used in all ways as a selection.
Inverting a selection
With a single click of the mouse it is possible to invert a selection. Just click the Invert Selection button (as above). Another way to describe this is that the Invert selection button selects everything that is not selected.
The selection has been inverted.
This selection can be viewed and analysed. Remember that a selection is a temporary table and as such can be mapped, browsed, graphed and used in many ways the same as any other table.
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Article by Tom Probert, Editor of "The MapInfo Professional" journal
When not writing articles for "The MapInfo Professional", Tom enjoys talking to MapInfo Professional users at conferences and events. When not working he likes to see movies with car chases, explosions and kung-fu fighting.