Is it a good idea to use oracle database to process the geometry data?

Question

I am working on a map related project. Here are the stops I need to do.
1. load geometry information from a table with spatial filter and other conditions (where clause)
2. get the points from the geometry column (sdo_geometry)
3. transform the coordinates
4. encoding the coordinates
5. output
We have a third party applicaiton that can do both #2 and #3. However the process is slow. Some quick tests show that all the steps from #1 to #4 can be done within oracle and the speed is faster. My concern is if it is a good approach to use oracle, a database server, to do all the data processing that can be done and normally shoudl be done on a web server.
Any adivce please?
(BTW, we use oracle 10g on windows 2008R2 64bit, and we may upgrate to 11g in about a year.)

Answer 1

Hi Simon,
Thanks for your help.
Yes all the steps can be done within the database side (Oracle). However I could do the same (extracting the coordinates from the sdo_geometry column, transforming the coordinates and encoding the coordinates) in .net code (web server side) by making use of the new verison of the odp.net. So I have to make a decision now to choose which approach to go, relying on Oracle server to do all the data processing or .net code. I am pretty sure Oracle can process a single request fairly quick, but if tens or even more concurrent requests for the process, I have concerns over the performance or reliability of the database server, especially the server is (a kind of ) beyond of our control (in control of the midware, IS and network team). Somebody said database is just a database and for data storing and retrieving, but may not for processing the data.
Here is more information regarding what we are doing. We use Google Map API to disply parcels. Each time the map is loaded, panned, zoomed, or refreshed (and so on), we need to query the database with spatial filter and some other criteria. The result will be tens or up to handreds of parcels containing hundreds to thousands of coordinates that are extracted from the parcel table that has a sdo_geometry column. We are expecting tens to hundreds of these requests every minute.
Now I am trying to chain every step together and do some tests using both appoachs in order to see which way is more effient and promising. I am guessing there won't be too much difference in terms of the performance for some simple testing unless I run some load testing, or if somebody like you guys can help me out.
1. load geometry information from a table with spatial filter and other conditions (where clause)
Regarding the issues you asked:
====================================
I assume you mean something like: Yes
CREATE TABLE load_table AS SELECT ID, GEOM FROM base_table where SDO_INSIDE(....) = 'TRUE';
2. get the points from the geometry column (sdo_geometry)
I assume you mean something like: Yes
SELECT ID, v.x, v.y FROM load_table l, TABLE(sdo_util.getVertices(l.geom)) t;
(See last comment about data.)
The problem is that we need a lot more information on what it is that you want to do in steps 3 - 5.
3. Transform the coordinates.
What sort of transformation? Rotation, Shift, Scale, Coordinate rounding? Transform from UTM to LatLng
4. Encoding the coordinates
What do you mean by this? Write them out as WKT/KML/GML? Google map encoded polylines
5. Output
Again, output to what, where? A new table? A shapefile? A text file? JSONP formatted data
Also, if you can provide a single sdo_geometry object + data and some example SQL it would help as well.
Here is an example where I take a geometry, rotate it (cf 3. Transform), extract vertices (2. get points), encode it (4. Encoding), and then output to screen (5. Output).
WITH myGeom As (
SELECT 1 as id,
MDSYS.SDO_GEOMETRY(2006, NULL, NULL, MDSYS.SDO_ELEM_INFO_ARRAY(1,2,1,5,2,1), MDSYS.SDO_ORDINATE_ARRAY(355600.52, 5407396.19, 361365.32, 5408106.36, 356488.27, 5409242.37, 357437.46, 5406457.67)) as geom
FROM DUAL
SELECT g.id || ',' || t.x || ',' || t.y as csv
FROM myGeom g,
TABLE (sdo_util.getVertices(
GEOM.Rotate(p_geometry => g.geom,
p_tolerance => 0.005,
p_rotatePt => MDSYS.SDO_Point_Type(357437.46,5406457.67,NULL),
p_rotation => 45 ))) t;
-- Results
CSV
1,355474.91,5405822.39
1,359049.08,5410400.89
1,354797.2,5407755.57
1,357437.46,5406457.67
Now show us what it is you want to do!!
Edited by: James Dong on May 31, 2012 11:41 AM