# Spatial Match Behavior

The behavior of the Spatial Match tool depends on the intersection method selected (Intersects, Contains or Within) and the types of the objects being tested.  The tables below list the various combinations.

## Intersects

 A Spatial Object... intersects a... if... The type of the returned intersection object (if requested) is... Polygon Polygon the polygons share any area. Touching edges without overlap is not considered an intersect. Polygon Polygon Line the line touches the edge or interior of the polygon Polyline Polygon Point the polygon contains the point Point Line Line any part of the lines cross each other or share endpoints Point Note: Lines may intersect at multiple points, in which case 1 point is returned and a warning is issued. Line Point the point is a vertex of the line. Note: A line may cross over a point geometrically without a vertex there, and this is not counted as an intersection. Point MultiPoint any object if it intersects any of the points MultiPoint Point Point the points are the same Point

## Contains & Within

 A TARGET... Contains a UNIVERSE... if... Polygon Polygon 99.99% of the second polygons area lies inside the first polygon. Polygon Line 99.99% of the length of the line lies inside the polygon. Polygon Point the point is inside the polygon Polygon MultiPoint all the points are in the polygon. Line Polygon Never. Line Line Every segment (i.e. 2-point series) in the contained line also appears in the containing line.  Segments consisting of the same 2 points in the opposite order (i.e. coded in the opposite direction) will still match.  Lines that follow the same route geometrically may still not match if one uses more (unnecessary) points. Line Point the point is a vertex of the line.   Note: A line may cross over a point geometrically without a vertex, and the line will not be counted as containing the point. Line MultiPoint all the points are vertexes of the line. MultiPoint MultiPoint all the universe points are in the target. MultiPoint Point one of the points are in the MultiPoint. MultiPoint Polygon or Line Never. Point Polygon Never. Point Line Never. Point Point The points are the same.

Note: If specifying a Calgary (cydb) file, be aware that the Calgary spatial index uses 5 decimal places of accuracy for compression and speed.  The YXDB spatial index uses 6 decimal places.  This adds an addition round off error of up to a maximum of 1.8 feet to Calgary indexes.  In other words, it is possible that a point can be 1.8 feet inside of a polygon and be found as outside in Calgary.