package com.esri.hadoop.hive;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.io.BytesWritable;
// DoubleWritable - must use hive-serde2; the other one produces struct {value:d.d}
import org.apache.hadoop.hive.serde2.io.DoubleWritable;
import com.esri.core.geometry.Geometry;
import com.esri.core.geometry.GeometryEngine;
import com.esri.core.geometry.MultiPath;
import com.esri.core.geometry.Point;
import org.apache.hive.pdk.HivePdkUnitTest;
import org.apache.hive.pdk.HivePdkUnitTests;
import com.esri.core.geometry.ogc.OGCGeometry;
@Description(name = "ST_GeodesicLengthWGS84",
value = "_FUNC_(line) - returns distance along line on WGS84 spheroid, in meters, for geographic coordinates",
extended = "Example:\n"
+ " SELECT _FUNC_(ST_Linestring(0.0,0.0, 0.3,0.4)) FROM src LIMIT 1; -- 55km\n"
+ " SELECT _FUNC_(ST_Linestring(0.0,80.0, 0.3,80.4)) FROM src LIMIT 1; -- 45km\n"
)
@HivePdkUnitTests(
cases = {
@HivePdkUnitTest(
query = "select substr(ST_GeodesicLengthWGS84(ST_GeomFromText('LineString(0 0, 0.03 0.04)', 4326)), 1, 5) from onerow",
result = "5542."
),
@HivePdkUnitTest(
query = "select substr(ST_GeodesicLengthWGS84(ST_GeomFromText('MultiLineString((0 80, 0.03 80.04))', 4326)), 1, 5) from onerow",
result = "4503."
),
@HivePdkUnitTest(
query = "select ST_Length(null) from onerow",
result = "null"
)
}
)
public class ST_GeodesicLengthWGS84 extends ST_GeometryAccessor {
public static final DoubleWritable resultDouble = new DoubleWritable();
static final Log LOG = LogFactory.getLog(ST_GeodesicLengthWGS84.class.getName());
public DoubleWritable evaluate(BytesWritable geomref) {
if (geomref == null || geomref.getLength() == 0) {
LogUtils.Log_ArgumentsNull(LOG);
return null;
}
int WGS84 = 4326;
if (GeometryUtils.getWKID(geomref) != WGS84) {
LogUtils.Log_SRIDMismatch(LOG, geomref, WGS84);
return null;
}
OGCGeometry ogcGeometry = GeometryUtils.geometryFromEsriShape(geomref);
if (ogcGeometry == null){
LogUtils.Log_ArgumentsNull(LOG);
return null;
}
Geometry esriGeom = ogcGeometry.getEsriGeometry();
switch(esriGeom.getType()) {
case Point:
case MultiPoint:
resultDouble.set(0.);
break;
default:
MultiPath lines = (MultiPath)(esriGeom);
int nPath = lines.getPathCount();
double length = 0.;
for (int ix = 0; ix < nPath; ix++) {
int curPt = lines.getPathStart(ix);
int pastPt = lines.getPathEnd(ix);
Point fromPt = lines.getPoint(curPt);
Point toPt = null;
for (int vx = curPt+1; vx < pastPt; vx++) {
toPt = lines.getPoint(vx);
length += GeometryEngine.geodesicDistanceOnWGS84(fromPt, toPt);
fromPt = toPt;
}
}
resultDouble.set(length);
break;
}
return resultDouble;
}
}