Spatial Solutions Architect and Database Expert
Today (25th February 2015) I uploaded the following changes to the following packages: 1. TESSELATE Reduce complexity of package interface. Removed all Quad_Tree Initialise procedures (Quad_Tree functions internally initialise). All SPACE_KEY functions removed: package now only supports morton key generation. Added new ST_TileGeometry functions that provide greater options for tiling (or generating a regular gridRead More
I gave a presentation on analyzing Oracle Spatial and Graph 12c’s performance by comparing it with two other spatial types known for their performance or quality. The slides from this presentation are available on this website
One issue that confuses a lot of spatial database practitioners is that the result of measuring the distance between a geometry object inside a polygon and that polygon’s boundary is zero (0). Here is an example. This looks like: Standard distance determination shows the problem: Here is a trick that will allow for the calculationRead More
The Spatial Companion 4 Oracle (SC4O) package (built using Java Topology Suite components) contains a method called ST_PolygonBuilder that can then form polygons from linestrings. However, ST_PolygonBuilder will not form polygons where it detects an unformed intersection: in this situation ST_PolygonBuilder has to be used with another SC4O method called ST_NodeLinestrings. ST_NodeLinestrings forms all intersectionsRead More
I have published a number of times and implementation of functions what would extract a specific point from any geometry object. These appear in my LINEAR PL/SQL package and the T_GEOMETRY object that was published as part of the PACT book I wrote with Dr Siva Ravada. When working for a customer recently I hadRead More
Oracle Spatial offers two ways of storing a single point: In SDO_POINT_TYPE structure In SDO_ORDINATE_ARRAY Examples include: SDO_GEOMETRY(2001,NULL,SDO_POINT_TYPE(12, 14, NULL),NULL,NULL)) SDO_GEOMETRY(2001,NULL,NULL,SDO_ELEM_INFO_ARRAY(1,1,1),SDO_ORDINATE_ARRAY(12,14)) Oracle recommends the storage of single points using the SDO_POINT_TYPE structure. There are, of course, a number of situations where this is not possible or recommended: Storage using the SDO_POINT_TYPE structure is impossible ifRead More
I have written an analysis of Oracle 12c’s new spatial performance improvements. The analysis was conducted by comparing what Oracle is offering in Oracle Spatial 12c against two other database types that have a reputation for performance and functionality. The report is available at the following link Accessing the Improvements These spatial performance improvements areRead More
For those not on 12cR1, or even perhaps if you are, the following two requirements came about at a customer site recently. Aggregate Append At that site (running 11gR2), there arose a need to aggregate all the islands of Australia into a single multi-polygon sdo_geometry. The first approach was to use SDO_AGGR_UNION (the customer isRead More
A customer presented me with an interesting problem. For some reason, a geodetic polygon object (4283) had been created within their database. (Probably an external application that supports circular arcs in geodetic polygons – SQL Server 2012 does.) The problem then was that the polygon needed to be transformed (projected) to a planar SRID. ValidatingRead More
While at my current contract employer, two functions were required to handle the conversion of DIMINFO SDO_LB/SDO_UB ranges to optimised rectangles (SDO_GEOMETRY) and the reverse. Note: GeoRaptor provides such capability for selected DIMINFO objects or to convert a map extent to its equivalent DIMINFO structure. The functions, written in PL/SQL are: ST_Diminfo2Rectangle ST_Geom2Diminfo The definitionRead More