This little tutorial shows what can be done using object tables with Sdo_Geometry. Let us imagine that we have a table of FAUNA observations and wish to relate the observation to the cartographic MAPSHEET it falls within. Yes, this can be done via attribute based foreign keys but I thought I would show how toRead More
UPDATES This article is left here for historical reasons only. From 12C onwards all of the SDO_GEOM package is available to Locator users. However, SDO_GEOM.SDO_LENGTH, when given an XYZ linestring will only return its 2D length for Locator users but its slope length for Enterprise users. Spatial Companion For Oracle (SC4O) – See end ofRead More
After much trial and error at a couple of customer sites, I worked out how to get FAST REFRESHing of materialized views that contain Sdo_geometry columns. The following points give you a starting guide. Yes, the Oracle documentation really is your best source of information, but sometimes being able to see how others made itRead More
Someone asked on Oracle Technet recently about how to compute the Australian AMG/MGA (UTM) zone from longitude latitude data (geographicals) expressed in NAD84. My solution is via a single SQL statement as follows (the first statement is just to show the SRIDs associated with the right projections.
When working with SHP files be aware that polygon data with holes or multi-part polygons (with/without hole) can often have holes (2003) and multi-parts (1003) with the wrong rotation. Wrong rotation is for outer shells (1003) that means Clockwise as against Clockwise and for inner shells or holes (2003) this means anti-clockwise when they shouldRead More
My friend, Andrew Hallam just pointed out something that I missed. Microsoft is developing a new release of SQL Server that includes capability for “geographic” data. Note the “geographic” down near the bottom of this press release on Katmai Also this note on the future version of SQL Server Supposedly scheduled to ship in 2008Read More
Questions are often raised about the significance of the SDO_LB and SDO_UB fields of the SDO_DIM_ELEMENT structures that define the spatial extent of the dimensions (SDO_DIM_ARRAY) of a table/column in Oracle’s metadata tables (accessed via the USER_SDO_GEOM_METADATA and ALL_SDO_GEOM_METADATA views). The structure of the the ALL_SDO_GEOM_METADATA view is: An MDSYS.SDO_DIM_ARRAY is an array of MDSYS.SDO_DIM_ELEMENTsRead More
This article was first written for Earth Observation Magazine in 2004. It is still accessible but only on the web archive, so I thought I would take a copy. SOAPBOX Insularity and Progress Simon Greener Original Article My 20 years in IT and GIS range from general IT on mainframes to GIS consulting in businessRead More
I was asked by Ross Caldow from Geomatic Technologies to give a presentation at an Oracle Spatial Forum held in Melbourne, Victoria on April 26th. The talk I gave was a technical one called “Oracle Spatial – inside the square”:http://www.spatialdbadvisor.com/file_download/20. The idea behind the talk was to show how other Oracle components freely available inRead More
This article has been a long time in gestation. Sure, I could have written it anytime in the past 12 months, but it is just has not been in my top 10 jobs: paid work always takes preference to “labours of love” The ESRI value-add conundrum For anyone selling software in the GIS industry oneRead More