Simplifying geometries

Question

Hi,
I need to simplify a layer of geometries. I have a roads table with 30,000 records and need to reduce the complexity of the data by reducing the number of points in each record. How can I achieve this in Oracle?
Keith.

Answer 1

Keith,
This is VERY easy. Depending on what other data you have (and assuming that you want to keep the original data intact), you could either copy the entire table, or add another SDO_GEOMETRY column.
Next, you could just do something like:
UPDATE datatable a
SET simple_geom = SDO_UTIL.SIMPLIFY(a.complex_geom, 0.5);
To make this happen as you insert and update records (assuming the complex and simple geometries are in the same table) you could use a trigger such as:
CREATE TRIGGER datatable_iutrg
BEFORE UPDATE OR INSERT on datatable FOR EACH ROW
BEGIN
:NEW.simple_geom := SDO_UTIL.SIMPLIFY(:NEW.complex_geom, 0.5);
END;
/