| Bug #27804 | funtion Contains(g1,g2) return more g1 completely contains g2 | ||
|---|---|---|---|
| Submitted: | 13 Apr 2007 9:40 | Modified: | 23 Jun 2007 19:58 |
| Reporter: | tuan tran | Email Updates: | |
| Status: | No Feedback | Impact on me: | |
| Category: | MySQL Server: General | Severity: | S2 (Serious) |
| Version: | 5.0 | OS: | Windows |
| Assigned to: | CPU Architecture: | Any | |
[13 Apr 2007 9:40]
tuan tran
[13 Apr 2007 10:36]
Valeriy Kravchuk
Thank you for a problem report. Please, specify the exact version of MySQL server used, 5.0.x, and send complete test case that demonstrates the behaviour described. Just copy and paste statements and results from mysql command line client.
[13 May 2007 23:02]
Bugs System
No feedback was provided for this bug for over a month, so it is being suspended automatically. If you are able to provide the information that was originally requested, please do so and change the status of the bug back to "Open".
[14 May 2007 10:51]
tuan tran
Hi you!
i have the table tbl_commune(Commune_Code INTEGER, Commune_Name VARCHAR(50), geom GEOMETRY, ...).
the colums geom contains polygons ( it can be multipolygon). When i try funtion Contains(g1,g2). g1 is geom, g2 is Point(x,y). The function return more than 1 object contain g2.
i found the problem that MySQL server 5.0 (mysql-essential-5.0.24a-win32.msi) use function Contains(g1,g2) with the results is minimum bound rectangle (MBR) .
when i user the function contains in mysql i check with my function:
public class findcontains {
/********************************************************
*
* @param P0
* @param P1
* @param P2
* @return
*/
private static double isLeft(Coordinate P0, Coordinate P1,Coordinate P2){
double tem= (P1.x - P0.x) * (P2.y - P0.y) - (P2.x - P0.x) * (P1.y - P0.y);
return tem;
}
/***********************************************************
* wn_PnPoly(): winding number test for a point in a polygon
* @param P= a point
* @param V [] = vertex points of a polygon V[n+1] with V[n]=V[0]
* @return wn = the winding number (=0 only if P is outside V[])
*/
private static int wn_PnPoly( Coordinate P, Coordinate[] V )
{
int wn = 0; // the winding number counter
int n=V.length-1;
// loop through all edges of the polygon
for (int i=0; i<n; i++) { // edge from V[i] to V[i+1]
if (V[i].y <= P.y) { // start y <= P.y
if (V[i+1].y > P.y) // an upward crossing
if (isLeft( V[i], V[i+1], P) > 0) // P left of edge
++wn; // have a valid up intersect
}
else { // start y > P.y (no test needed)
if (V[i+1].y <= P.y) // a downward crossing
if (isLeft( V[i], V[i+1], P) < 0) // P right of edge
--wn; // have a valid down intersect
}
}
//System.out.println("wn="+wn);
return wn;
}
/***********************************************************
* Caculate Geometry contains Point P?
* @param geom :object Geometry
* @param p: Point
* @return :
* true: contain
* false: not contain
*/
public static boolean Contains(Geometry geom,Coordinate p){
Coordinate[] V=geom.getCoordinates ();
return (wn_PnPoly(p,V)>0);
}
}
The results is same the function in Postgree .
Thanks!
[23 May 2007 12:33]
Valeriy Kravchuk
Please, try to repeat with a newer version, 5.0.41, and inform about the results.
[23 May 2007 13:46]
tuan tran
Do you understand my question?
[23 May 2007 19:58]
Valeriy Kravchuk
> Do you understand my question? Maybe, not. Please, help me, by providing a complete test case, with exact CREATE TABLE, some INSERT statements and SELECT with Contains() function that demonstrates wrong results. All I understand now is that you have a "proper" implementation of Contains() for your test case, and that you got "incorrect" results with old MySQL version.
[23 Jun 2007 23:00]
Bugs System
No feedback was provided for this bug for over a month, so it is being suspended automatically. If you are able to provide the information that was originally requested, please do so and change the status of the bug back to "Open".
