line intersection utility and envelope methods

Author: bosborn

CHANGELOG.md

@@ -6,7 +6,8 @@ Adheres to [Semantic Versioning](http://semver.org/).
 
 ## 2.0.7 (TBD)
 
-* TBD
+* Line intersection geometry utility
+* GeometryEnvelope is empty and contains methods
 
 ## [2.0.6](https://github.com/ngageoint/simple-features-java/releases/tag/2.0.6) (04-18-2022)
 

src/main/java/mil/nga/sf/GeometryEnvelope.java

@@ -1,13 +1,20 @@
 package mil.nga.sf;
 
+import java.io.Serializable;
+
 import mil.nga.sf.util.GeometryEnvelopeBuilder;
 
 /**
  * Geometry envelope
  * 
  * @author osbornb
  */
-public class GeometryEnvelope {
+public class GeometryEnvelope implements Serializable {
+
+	/**
+	 * Serial Version UID
+	 */
+	private static final long serialVersionUID = 1L;
 
 	/**
 	 * Min X
@@ -467,6 +474,16 @@ public Point getCentroid() {
 		return new Point((minX + maxX) / 2.0, (minY + maxY) / 2.0);
 	}
 
+	/**
+	 * Determine if the envelope is empty
+	 * 
+	 * @return true if empty
+	 * @since 2.0.7
+	 */
+	public boolean isEmpty() {
+		return getXRange() <= 0.0 || getYRange() <= 0.0;
+	}
+
 	/**
 	 * Determine if intersects with the provided envelope
 	 *
@@ -556,6 +573,33 @@ public GeometryEnvelope union(GeometryEnvelope envelope) {
 		return union;
 	}
 
+	/**
+	 * Determine if contains the point
+	 *
+	 * @param point
+	 *            point
+	 * @return true if contains
+	 * @since 2.0.7
+	 */
+	public boolean contains(Point point) {
+		return contains(point.getX(), point.getY());
+	}
+
+	/**
+	 * Determine if contains the coordinate
+	 *
+	 * @param x
+	 *            x value
+	 * @param y
+	 *            y value
+	 * @return true if contains
+	 * @since 2.0.7
+	 */
+	public boolean contains(double x, double y) {
+		return x >= getMinX() && x <= getMaxX() && y >= getMinY()
+				&& y <= getMaxY();
+	}
+
 	/**
 	 * Determine if inclusively contains the provided envelope
 	 *

src/main/java/mil/nga/sf/util/GeometryUtils.java

@@ -21,6 +21,7 @@
 import mil.nga.sf.Geometry;
 import mil.nga.sf.GeometryCollection;
 import mil.nga.sf.GeometryType;
+import mil.nga.sf.Line;
 import mil.nga.sf.LineString;
 import mil.nga.sf.MultiLineString;
 import mil.nga.sf.MultiPoint;
@@ -1140,6 +1141,59 @@ private static boolean pointOnPath(Point point, List<Point> points,
 		return onPath;
 	}
 
+	/**
+	 * Get the point intersection between two lines
+	 * 
+	 * @param line1
+	 *            first line
+	 * @param line2
+	 *            second line
+	 * @return intersection point or null if no intersection
+	 * @since 2.0.7
+	 */
+	public static Point intersection(Line line1, Line line2) {
+		return intersection(line1.startPoint(), line1.endPoint(),
+				line2.startPoint(), line2.endPoint());
+	}
+
+	/**
+	 * Get the point intersection between end points of two lines
+	 * 
+	 * @param line1Point1
+	 *            first point of the first line
+	 * @param line1Point2
+	 *            second point of the first line
+	 * @param line2Point1
+	 *            first point of the second line
+	 * @param line2Point2
+	 *            second point of the second line
+	 * @return intersection point or null if no intersection
+	 * @since 2.0.7
+	 */
+	public static Point intersection(Point line1Point1, Point line1Point2,
+			Point line2Point1, Point line2Point2) {
+
+		Point intersection = null;
+
+		double a1 = line1Point2.getY() - line1Point1.getY();
+		double b1 = line1Point1.getX() - line1Point2.getX();
+		double c1 = a1 * (line1Point1.getX()) + b1 * (line1Point1.getY());
+
+		double a2 = line2Point2.getY() - line2Point1.getY();
+		double b2 = line2Point1.getX() - line2Point2.getX();
+		double c2 = a2 * (line2Point1.getX()) + b2 * (line2Point1.getY());
+
+		double determinant = a1 * b2 - a2 * b1;
+
+		if (determinant != 0) {
+			double x = (b2 * c1 - b1 * c2) / determinant;
+			double y = (a1 * c2 - a2 * c1) / determinant;
+			intersection = new Point(x, y);
+		}
+
+		return intersection;
+	}
+
 	/**
 	 * Determine if the geometries contain a Z value
 	 *