Spatial Solutions Architect and Database Expert
Other blog postings of mine have shown how the layer_gtype keyword in the PARAMETERS clause of an RTree spatial index can be used to constrain the sdo_geometry type being stored in a column. Remember, SDO_GEOMETRY is singly inherited: there is no POINT, CURVE, POLYGON etc sub-type. For this one must use the SQL/MM Type shippedRead More
Recently I was asked to review a database migration from one vendor’s database to another’s. The conversion involved geospatial data and database internal representations. I am not going to talk about who the client was, or what actually transpired, but the final report I submitted was edited by the client and the phrase “to industry-bestRead More
Over on Technet , the following question was asked: My question is, can you think of a way to recognize situations like this and merge and store them in a table before, we attempt mapping and spatial queries are performed? The following database level approach is one approach for ensuring any loader doesn’t load duplicateRead More
Over the past week I have been having a conversation with a customer around problems with using CASE WHEN THEN ELSE END constructs in SQL for turning WKT into SDO_GEOMETRY objects on INSERT. Now the customer was doing this sort of comparison for correctly processing WKT data values in an external file into SDO_GEOMETRY andRead More
I have been emailed by someone who is using ESRI’s sde.st_geometry in preference to Oracle’s SDO_GEOMETRY or ST_GEOMETRY for their spatial data storage in Oracle, wanting a version of my CENTROID pl/sql package that would allow for its use with ESRI’s spatial data type. This is what I was asked: First off love your blog,Read More
Changes to the CENTROID and TESSELATE packages, as well as a modification of the Windows install.cmd tool (improved error handling) and the method used to test for an XE database required a new upload of the two affected zip files holding the relevant packages and tools.
My original CENTROID package’s sdo_centroid() functions, when supplied with a multilinestring sdo_geometry, would “explode” the multilinestring into its component linestrings and calculate the centroid (mid-point) of the largest linestring. Some users have asked for the centroid package to return the centroid (midpoint) of the whole multilinestring. While the LINEAR package can do this, I haveRead More
Even old dogs like me forget things and have to learn them again. You know, I am sure that I knew that SDO_GEOM.RELATE was a Spatial licensed feature and not available in Locator, but I clean forgot until a situation with a customer required me to look at an alternative. The reason is because thisRead More
I received a question from a respected colleague: Can the parameters of a spatial index be altered? I created several dozen spatial indexes with a layer_gtype of polygon, I now have a requirement to modify them to be multipolygon…. My colleague wishes to do this without dropping the existing index. The answer to this isRead More
My EXPORTER package + Java code has functions called WriteExcelSpreadsheet that can be used to create and export any SQL SELECT statement to disk as an Excel Spreadsheet using Oracle database’s DBMS_JOB or DBMS_SCHEDULER. Because Excel Spreadsheets have limited number of rows (65535) and columns (255) per sheet (the maximum size of data in aRead More