Set Values For Node Snap & Thinning Dialog Box - MapInfo_Pro - 2023

MapInfo Pro Help

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MapInfo Pro
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MapInfo Pro Help
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2023-09-12
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2023-09-12T16:39:16.995000

Inter-Object Node Snap

Use the Inter-Object Node Snap values to snap nodes from different objects together. This can be used to eliminate overlaps and gaps in region objects and to connect polyline objects that are closed, but do not touch each other.

Enable Node Snap

Used for the end nodes of a polyline. When two nodes in the same or in different objects are within the snap tolerance of each other when you select Enable Node Snap, MapInfo Pro will treat these nodes as if they occupy the same point.

End Node Tolerance

End Node tolerance is used for the end nodes of a polyline. When two end nodes in the same or in different objects are within the snap tolerance of each other when you select End Node Tolerance, then one or both of those nodes will be moved such that they occupy the same point (for example, they will be snapped together).

Internal Node Tolerance

The Internal Node tolerance is used for all other non-end point nodes of a polyline. In many cases, the End Node and Internal Node tolerance should be set to the same values, but the ability exists to set them separately.

Tolerance Units

The unit of measurement for the Inter-Object Node Snap values. The distance measurements are always calculated using Cartesian methods, never using spherical methods. Tables that are in a Latitude/Longitude coordinate system will not measure these tolerances accurately.

Node Thinning/Generalization

The Thinning/Generalization values are used to generalize objects by removing nodes while retaining the shape of the object. When thinning region objects, shared boundaries will be retained.

Enable Node Thinning/Generalization

Removes Polygon/Polyline nodes when a 2-node sequence is almost linear or nodes are close together.

3-Node Collinear Delineation

The Thinning/Generalization values can be used to generalize objects by removing nodes while retaining the shape of the object. The 3-Node Collinear Deviation value will measure how co-linear a set of 3 successive nodes in the object are. Take the three nodes and connect them in a closed triangular shaped object. Measure the perpendicular distance between the second node and the line segment connecting the first and the third nodes. If the distance is less than or equal to the 3-Node Collinear Deviation distance, then the three points are considered collinear, and the middle (second) point is removed from the object.

Node Separation

Designate a tolerance used to thin nodes within an object that are close together. If two successive nodes in an object are closer than the Distance tolerance, then one of the nodes is removed from the object.

Distance Units

Sets the unit of measurement for the Thinning/Generalization values.

Polygon Area Thinning

Polygon Area Thinning is used to remove small polygons from the result set. Polygons that are smaller in area than the Minimum Area value are automatically removed. The polygon can be part of a multi-polygon region, in which case only that polygon is removed from the region, and the rest of the polygons in the region are retained. The areas are calculated using the Cartesian method. Tables that are in a Latitude/Longitude coordinate system will not measure these tolerances accurately.

Enable Polygon Area Thinning

Polygons smaller than this area are removed.

Minimum Area

Designate a minimum area. Polygons that are smaller in area than the Minimum Area value are automatically removed.

Area Units

Sets the unit of measurement for the Polygon Area. The areas are calculated using the Cartesian method.