Geodetic spatial queries - sdo_relate

Question

Hello,
The following script populates a spatial table with points on a query boundary and then queries that table using the query boundary. When using a srid of 8307 not all of the points are returned using sdo_relate. If the srid is NULL then all points 'on' the query boundary are returned.
In https://metalink.oracle.com/metalink/plsql/f?p=130:15:2437246749596129570
there is the statement...
"In a geodetic system, if there is a line defined from lat: 50, long: 30, lat:50, long: 35 that line does not go along the latitude 50 parallel.
Only the two end points will be at lat: 50, all the other interior points on that line will have a latitude value more than 50.
Due to this reason, the points along the lat: 50 are not part of the query window. "
Does anyone know the reasoning behind this statement? How can I determine what the interior points would be between a line defined as start point lat: 50, long: 30 to end point lat:50, long: 35?
Thanks in advance,
Rick
========= Script follows ============
geomdetic relate test case
This script demonstrates cases where sdo_relate, in a geodetic coordate system where
"A two point line on a given meridian, doesn't necessarily follow that meridian,
so any feature touching that meridian between those two points is not necessarily
touching that line""
The script generates an input query boundary using max and min values. It inserts
point features on the query boundary at input interval into a test table. '
A spatial query is executed against the test table using the query boundary.
DECLARE
TYPE ord_type IS TABLE OF NUMBER
INDEX BY BINARY_INTEGER;
x_tab ord_type;
y_tab ord_type;
maxlon NUMBER DEFAULT 65;
minlon NUMBER DEFAULT 64;
maxlat NUMBER DEFAULT 45 ;
minlat NUMBER DEFAULT 44;
INCREMENT NUMBER DEFAULT 0.001;
offset number default 0;
srid number default 8307;
curval NUMBER;
objectnotexists EXCEPTION;
PRAGMA EXCEPTION_INIT (objectnotexists, -942);
indexnotexists EXCEPTION;
PRAGMA EXCEPTION_INIT (indexnotexists, -1418);
PROCEDURE populate_array (
p_minval IN NUMBER,
p_maxval IN NUMBER,
p_increment IN NUMBER,
p_array IN OUT ord_type
IS
i BINARY_INTEGER DEFAULT 0;
BEGIN
curval := p_minval;
LOOP
p_array (i) := curval;
curval := curval + INCREMENT;
i := i + 1;
EXIT WHEN curval > p_maxval;
END LOOP;
END populate_array;
PROCEDURE insert_points_on_tangent (
p_tangent IN NUMBER,
p_ords IN ord_type,
orientation IN VARCHAR
IS
v_geom MDSYS.SDO_GEOMETRY;
i BINARY_INTEGER;
BEGIN
i := p_ords.FIRST; -- get subscript of first element
WHILE i IS NOT NULL
LOOP
IF orientation = 'Y'
THEN
v_geom :=
MDSYS.SDO_GEOMETRY (2001,
srid,
NULL,
MDSYS.sdo_elem_info_array (1, 1, 1),
MDSYS.sdo_ordinate_array (p_tangent,
p_ords (i)
ELSE
v_geom :=
MDSYS.SDO_GEOMETRY (2001,
srid,
NULL,
MDSYS.sdo_elem_info_array (1, 1, 1),
MDSYS.sdo_ordinate_array (p_ords (i),
p_tangent
END IF;
EXECUTE IMMEDIATE 'insert into sdo_relate_geom_test (geom, geom_type) values (:boundary, :geom_tag)'
USING v_geom, orientation || ' ' || i;
i := p_ords.NEXT (i); -- get subscript of next element
END LOOP;
END insert_points_on_tangent;
-- Create a table to hold the geometries.
PROCEDURE TEST
IS
v_geom MDSYS.SDO_GEOMETRY
DEFAULT MDSYS.SDO_GEOMETRY (2003,
srid,
NULL,
MDSYS.sdo_elem_info_array (1, 1003, 1),
MDSYS.sdo_ordinate_array (minlon,
minlat,
maxlon,
minlat,
maxlon,
maxlat,
minlon,
maxlat,
minlon,
minlat
v_viewportgeom MDSYS.SDO_GEOMETRY
DEFAULT MDSYS.SDO_GEOMETRY (2003,
0,
NULL,
MDSYS.sdo_elem_info_array (1, 1003, 1),
MDSYS.sdo_ordinate_array (minlon,
minlat,
maxlon,
minlat,
maxlon,
maxlat,
minlon,
maxlat,
minlon,
minlat
v_expected NUMBER;
v_relate_results NUMBER;
v_filter_results NUMBER;
v_relate_results_arc NUMBER;
v_dimino MDSYS.SDO_DIM_ARRAY;
v_count_sql VARCHAR2 (1000)
DEFAULT 'select count(*) from sdo_relate_geom_test';
v_filter_sql VARCHAR2 (1000)
DEFAULT 'SELECT count(*) '
|| ' FROM sdo_relate_geom_test '
|| ' WHERE MDSYS.sdo_filter '
|| ' (geom, '
|| ' :ingeom, '
|| ' ''MASK= ANYINTERACT QUERYTYPE=WINDOW'' '
|| ' ) = ''TRUE'' ';
v_relate_sql VARCHAR2 (1000)
DEFAULT 'SELECT count(*) '
|| ' FROM sdo_relate_geom_test '
|| ' WHERE MDSYS.sdo_relate '
|| ' (geom, '
|| ' :ingeom, '
|| ' ''MASK= ANYINTERACT QUERYTYPE=WINDOW'' '
|| ' ) = ''TRUE'' ';
BEGIN
EXECUTE IMMEDIATE v_count_sql
INTO v_expected;
EXECUTE IMMEDIATE v_filter_sql
INTO v_filter_results
USING v_geom;
EXECUTE IMMEDIATE v_relate_sql
INTO v_relate_results
USING v_geom;
DBMS_OUTPUT.put_line ( ' boundary minLat '
|| minlat
|| ' minLon '
|| minlon
|| ' maxLat '
|| maxlat
|| ' maxLon '
|| maxlon
||' increment '
|| INCREMENT
DBMS_OUTPUT.put_line ( 'expected '
|| v_expected
|| ' relate returned '
|| v_relate_results
|| ', '
|| 'filter returned '
|| v_filter_results
|| '. '
DBMS_OUTPUT.put_line('');
END TEST;
BEGIN
BEGIN
EXECUTE IMMEDIATE 'drop table sdo_relate_geom_test';
EXCEPTION
WHEN objectnotexists
THEN
NULL;
END;
EXECUTE IMMEDIATE 'create table sdo_relate_geom_test(geom mdsys.sdo_geometry, geom_type VARCHAR2(100))';
-- generate the points we want to test
populate_array (minlon, maxlon, INCREMENT, x_tab);
populate_array (minlat, maxlat, INCREMENT, y_tab);
-- insert the points on the query boundary
insert_points_on_tangent (minlon + offset, y_tab, 'Y');
insert_points_on_tangent (maxlon - offset, y_tab, 'Y');
insert_points_on_tangent (minlat + offset, x_tab, 'X');
insert_points_on_tangent (maxlat - offset, x_tab, 'X');
DELETE user_sdo_geom_metadata
WHERE table_name = 'SDO_RELATE_GEOM_TEST';
INSERT INTO user_sdo_geom_metadata
(table_name, column_name,
diminfo,
srid
VALUES ('SDO_RELATE_GEOM_TEST', 'GEOM',
MDSYS.sdo_dim_array (MDSYS.sdo_dim_element ('x',
-180,
180,
.00000005
MDSYS.sdo_dim_element ('y',
-90,
90,
.00000005
srid
BEGIN
EXECUTE IMMEDIATE 'drop index SDO_RELATE_GEOM_TEST_spa_idx';
EXCEPTION
WHEN indexnotexists
THEN
NULL;
END;
EXECUTE IMMEDIATE 'create index SDO_RELATE_GEOM_TEST_spa_idx on SDO_RELATE_GEOM_TEST(geom) indextype is mdsys.spatial_index';
TEST;
END;
/

Answer 1

In https://metalink.oracle.com/metalink/plsql/f?p=130:15:2437246749596129570
there is the statement...
"In a geodetic system, if there is a line defined from lat: 50, long: 30, lat:50, long: 35 that line does not go along the latitude 50 parallel.
Only the two end points will be at lat: 50, all the other interior points on that line will have a latitude value more than 50.
Due to this reason, the points along the lat: 50 are not part of the query window. "
Does anyone know the reasoning behind this statement? How can I determine what the interior points would be between a line defined as start point lat: 50, long: 30 to end point lat:50, long: 35?
In Oracle Spatial's support for geodetic coordinates, the line segments connecting consecutive vertices of a polygon or line string are geodesics - the shortest paths between the vertices on the earth spheroid. The shortest path between {30, 50} and {35, 50) does not coincide with the 50 latitude parallel, but goes to higher latitude. Only at the equator does the geodesic connecting points of constant latitude coincide with the latitude parallel.