Spatial Solutions Architect and Database Expert
In a previous article I showed how too many digits of precision for the ordinates of an sdo_geometry object – stored in its sdo_ordinate_array – has an effect on storage volume. In this article I will revisit the question of storage size while examining the effect that storage size has on performance (search and retrieval).Read More
The knowledgeable Bryan Hall made a post over on the Oracle Technology Network’s Oracle Spatial Forum reminding users of the “hidden” issues that inform the way Oracle compare’s two geometries when using a secondary filter Here is the relevant section of the post. With relationship operators such as sdo_anyinteract that take two parameters for theRead More
This article shows how to apply Delaunay triangulation and inverse distance weighting (IDW) techniques for soils interpolation in Oracle.
A question was asked on the Oracle Technology Network Spatial forum: I am trying to select sdo_gtype from all tables in schema, i mean to execute same sql statement given below for entire schema. Any help on the usage of dynamic sql in PLSQL to execute select statement for all tables in the schema. HereRead More
My CENTROID package is a very popular download from my website. In this article I want to expose a couple of issues that catch new users of my package. These issues are documented in the header of the relevant functions but because there is no separate end user documentation (other than the blog articles onRead More
Over the past 6 months or so I have been developing a set of functions, based on the Java Topology Suite (JTS) and JAvaSPAtial (Jaspa), which complement or extend the Oracle’s proprietary functions that process its SDO_Geometry objects. These functions were initially released using a PL/SQL package and related Java class called JTS. As theRead More
It is useful to have functions for converting from individual degrees, minutes and seconds to a single decimal degree value and back again. Here are some useful plPgSql functions. DMS2DD Firstly, a function to convert individual degrees, minutes and seconds values to a single decimal degree value. Now for some examples…. Result: dms2dd -44.1805555555556 Result:Read More
Recently I had need to convert a PL/SQL Oracle Spatial function I created years ago called FindCircle to SQL Server 2008 for use in another project. That function was original work already released to the public domain as part of my free COGO package for Oracle. Here is that function for SQL Server. Note thatRead More
One of the geoprocessing functions that seems to be poorly implemented is the ability to clip a polygon using one or more linestrings such that the result is a number of polygons. Here is an example of someone asking for help on the Oracle Technology Network’s Spatial forum: I have a task where i haveRead More
I have just added to my Java Spatial For Oracle (JS4O) project exposure of the JTS/Jaspa functions for: ST_IsValid ST_IsSimple ST_Dimension ST_CoordDim Here are the type signatures in the JTS PL/SQL package. Here is a test of these functions. I hope this is helpful to someone.