Mapviewer, parallel lines and custom rendering

Question

I have been scratching my head a bit on this:
We have some databases which contains various types of water/sewer-pipes. These lines (pipes) has an attribute connected to them, which describes displacement and ranges from -3 to 3 (where a "normal" centered lines is 0).
Since we are very interested in the mapviewer WMS-feature, and want to render the map just the way we do in our apps, I am wondering, is there some way I can implement "server-logic" to apply displacement to the lines according to the displacement-attribute ?
Thanks in advance,
Oyvind

Answer 1

Oyvind
You could use a view that references the original geometry (or just store it back in the same table in a different column), offsetting it to one side or the other using the LRS functions.
First, you’ll have to add an LRS value (unless you already have them) using SDO_LRS.CONVERT_TO_LRS_GEOM. Start and End could be 0 and 1.
Then offest that LRS geometry using SDO_LRS.OFFSET_GEOM_SEGMENT.
Then remove the LRS items (unless that doesn’t make any difference in your app):
CREATE OR REPLACE VIEW corrected_pipedata
(geom)
AS
SELECT SDO_LRS.CONVERT_TO_STD_GEOM( SDO_LRS.OFFSET_GEOM_SEGMENT( SDO_LRS.CONVERT_TO_LRS_GEOM(a.in_geom, 0, 1),
0, 1,
a.in_offset))
FROM pipedata a
Example:
SELECT geometry_l from c_path_segment WHERE rownum < 2;SDO_GEOMETRY(3002, 8307, *, SDO_ELEM_INFO_ARRAY(1, 2, 1), SDO_ORDINATE_ARRAY(-80.5460927551392, 28.4766171261354, 0, -80.5460869608106, 28.4766337523028, 0))
SELECT SDO_LRS.CONVERT_TO_STD_GEOM(SDO_LRS.OFFSET_GEOM_SEGMENT( SDO_LRS.CONVERT_TO_LRS_GEOM(a.geometry_l, 0, 1),0, 1,
-1 ,
0.005,
'unit=meter arc_tolerance=0.05'))
FROM c_path_segment a
WHERE rownum < 2;
SDO_GEOMETRY(3002, 8307, *, SDO_ELEM_INFO_ARRAY(1, 2, 1), SDO_ORDINATE_ARRAY(-80.5460833610681, 28.4766140113997, 0, -80.5460829955615, 28.4766144706575, 0, -80.546077201
2316, 28.4766310968245, 0))
SELECT SDO_LRS.CONVERT_TO_STD_GEOM(SDO_LRS.OFFSET_GEOM_SEGMENT( SDO_LRS.CONVERT_TO_LRS_GEOM(a.geometry_l, 0, 1),0, 1,
1 ,
0.005,
'unit=meter arc_tolerance=0.05'))
FROM c_path_segment a
WHERE rownum < 2;
SDO_GEOMETRY(3002, 8307, *, SDO_ELEM_INFO_ARRAY(1, 2, 1), SDO_ORDINATE_ARRAY(-80.5461024997426, 28.4766189245689, 0, -80.5461025147173, 28.4766197816126, 0, -80.546096720
3901, 28.4766364077804, 0, -80.546096182864, 28.4766370831801, 0))