/**
* Returns the z-coordinate value for point.
*
* @param node xml element containing gml object(s)
* @return z double value
* @throws QueryException query exception
*/
@Deterministic
public Dbl z(final ANode node) throws QueryException {
final Geometry geo = geo(node, Q_GML_POINT);
if (geo == null && checkGeo(node) != null)
throw GeoErrors.geoType(node.qname().local(), "Line");
return Dbl.get(geo.getCoordinate().z);
}
/**
* Checks if the specified, non-empty item is a double. Returns the double or throws an exception.
*
* @param it item to be checked
* @return number
* @throws QueryException query exception
*/
private ANum toNumber(final Item it) throws QueryException {
if (it.type.isUntyped()) return Dbl.get(it.dbl(info));
if (it instanceof ANum) return (ANum) it;
throw numberError(this, it);
}
@Override
public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
final Item it = exprs[0].atomItem(qc, info);
return it == null ? null : Dbl.get(sqrt(toDouble(it)));
}
/**
* Returns the area of a Geometry. Areal Geometries have a non-zero area. Returns zero for Point
* and Lines.
*
* @param node xml element containing gml object(s)
* @return geometry area as a double vaue
* @throws QueryException query exception
*/
@Deterministic
public Dbl area(final ANode node) throws QueryException {
return Dbl.get(checkGeo(node).getArea());
}
/**
* Returns the length of this Geometry. Linear geometries return their length. Areal geometries
* return their parameter. Others return 0.0
*
* @param node xml element containing gml object(s)
* @return length double value
* @throws QueryException query exception
*/
@Deterministic
public Dbl length(final ANode node) throws QueryException {
return Dbl.get(checkGeo(node).getLength());
}
/**
* Returns a polygon that represents all Points whose distance from this geometric object is less
* than or equal to distance. The returned element must be either gml:Polygon, gml:LineString or
* gml:Point.
*
* @param node xml element containing gml object(s)
* @param distance specific distance from the $geometry (the buffer width)
* @return buffer geometry as gml element
* @throws QueryException query exception
*/
@Deterministic
public ANode buffer(final ANode node, final Dbl distance) throws QueryException {
return gmlWriter(checkGeo(node).buffer(distance.dbl()));
}
/**
* Returns the shortest distance in the units of the spatial reference system of geometry, between
* the geometries. The distance is the distance between a point on each of the geometries.
*
* @param node1 xml element containing gml object(s)
* @param node2 xml element containing gml object(s)
* @return distance double value
* @throws QueryException query exception
*/
@Deterministic
public Dbl distance(final ANode node1, final ANode node2) throws QueryException {
final Geometry geo1 = checkGeo(node1);
final Geometry geo2 = checkGeo(node2);
return Dbl.get(geo1.distance(geo2));
}