Building polygons from overlapping linestrings requiring intersection

I received an email a few weeks ago asking: I was wondering if you could post an article explaining how to create a polygon from overlapping lines, if this is possible. I am new as in 1 week into exploring this product and am finding the documentation for ST_BuildArea and the like a little hardRead More

Loading and Processing GPX 1.1 files using Oracle XMLDB

There are a large number of geospatial data storage, delivery and interchange formats around nowadays. Including (I limit this discussion to vector data formats only): Geography Markup Language (GML) Keyhole Markup Language GPS eXchange Format (GPX) Vector Markup Language (VML) Scalable Vector Graphics (SVG) Victorian Government’s (Aust) Incremental Update Format (IUF) New South Wales Government’sRead More

Loading Spatial Data from an external CSV file in Oracle

There have been many, many articles written on the web describing how to access external data (data held in operating system files not under the control of Oracle and not stored within its own datafiles and tablespaces) from within Oracle such that one can query the data using SQL. In short, Oracle allows a userRead More

Calling the Oracle Spatial shapefile loader from within the Oracle database itself

Oracle makes available for download from its website a shapefile loader called shp2sdo. Loading data using this tool is a four step process: Execute shp2sdo to create a set of sqlplus and sqlldr files. Use SQLPlus to run the SQL file generated by shp2sdo to create the table and user_sdo_geom_metadata entries. Load the actual dataRead More

DMS2DD for PostGIS

Yesterday, I posted a short article on Converting Google Earth Formatted Longitude/Latitude points to decimal degrees. The Google Earth longitude/latitude values are expressed as a string containing degree, minute and seconds values with text separators as follows: Latitude Longitude 43� 0�50.60�S 147�12�18.20�E The function described was written in PL/SQL for Oracle. Regina Obe emailed meRead More