Category to group Oracle Server and Locator posts.
My CENTROID package has been downloaded thousands of times and, except from some initial problems appears to have performed flawlessly. Until now! The thing about spatial data is that, once you think you understand its intricacies it bites you for being so stupid! A user contacted me to let me know some use cases thatRead More
—————————————————————————————- UPDATE (21 Mar 2018): Wrapper functions have been added to the AFFINE package to provide easier access to the SDO_UTIL.AFFINETRANSFORMS function. The AFFINE package now supports three different implementations of most of its functions: Original PL/SQL functions ST_AFFINE based on SYS.UTL_NLA_ARRAY_DBL SDO_UTIL.AFFINETRANSFORMS Improved testing of the AFFINE functions has also been implemented. The AFFINERead More
Over on the Oracle Spatial Forum at the Technology Network, Wojciech asked the following question: My problem looks that way: lets say we have a point: I want to get a location of a point 50 miles east and 30 miles north from the point presented here. Do you know how to achieve this? ThereRead More
It is often observed that you cannot use an sdo_geometry object in an ORDER BY clause of a SELECT statement. This is demonstrated below. Test Data Now, if we try and sort this data we get: If you look at the SDO_GEOMETRY type you will see that it does not have a MAP or ORDERRead More
Oracle’s SDO_AGGR_UNION has always had horrible performance where the set of geometry objects to be unioned is somewhat more than trivial. (Trivial is not a well defined scientific term – experienced users of Oracle Spatial know what I am interfering.) The Oracle Spatial team were not unaware of the problems with their aggregate function. ToRead More
Often Oracle Locator/Spatial users want to know how to round the individual ordinates of the coordinates of an sdo_geometry. This article shows how this can be done. Background Oracle imposes no precision limit on the NUMBER that records an ordinate of a coordinate except that imposed by the NUMBER datatype itself. Also, while one associatesRead More
UPDATED: Fix in Order By and addition of second example. Here are some examples of how to construct linestrings from points stored in tables in two different formats. XYZ Values in SDO_POINT of SDO_GEOMETRY object The following example creates SDO_GEOMETRY point objects (2D) and stores them in a table linepoints. These points described individual featuresRead More
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.