I was asked the other day how to create a square buffer around a linestring (or set of linestrings). If you used my parallel function, then everything could be achieved as follows: Putting a PL/SQL function wrapper around this is trivial. I hope this helps someone.
Like many others out there, I often have a need to convert a decimal seconds value to its canonical equivalent as a string. Which this can be done using standard SQL I prefer to wrap the required conversion functions inside a function as follows. Which can be called as follows: HMS 3:43:33 3h43m33s I hopeRead More
This posting is to inform my readers that I am in the process of shutting down this website and, when done, it will become nothing more than a link to my new SPDBA website. There is no date for the final switch over; it will only happen when the articles etc have been moved.
I have been doing a lot of work recently with processing the errors reported by Oracle’s MDSYS.SDO_GEOM.VALIDATE_GEOMETRY_WITH_CONTEXT function. The results that are output from this function are not well documented with some outputs only being discovered by having bad geometries that generate those errors! But it was interesting for me to note that the functionRead More
The SDO_LENGTH function within SDO_GEOM package can be called with an optional unit parameter as in the following call signature: But what are a valid list of values for the unit parameter? For a start, if the SDO_GEOMETRY has a NULL SDO_SRID value then the unit parameter can’t be used at all! For other cases,Read More
In an article on Oracle I described how to convert Google Earth textual representations of a longitude or latitude value to its decimal equivalent. Here is a version that will work with SQL Server 2008/2012 Spatial. And here are a few examples. Result DD -43.0138888888889 43.5126388888889 147.841833333333 -65.1701666666667 I hope this is of use toRead More
Sometimes data is provided to spatial databases via spreadsheets or other database tables in the form of degrees, minutes and seconds values. For example, data may come like this: Degree Minute Seconds 45 30 30.0 Which then need converting to a single decimal degree floating point value for use as an ordinate in a spatialRead More
In my article on DD2DMS I outlined how to convert a latitude or longitude as a decimal degrees value to a formatted string. This article describes a function, DMS2DD that reverses those values back to a single decimal degree value. Note that I have a schema call cogo in which I create functions like this.Read More
Many years ago I had need to annotate the lines of a cadastral (land titles) polygon with the bearing and distance of each line. The bearings and distances need to be computed from the boundary of each land parcel. The annotation had to be formatted as DD^MM’SS.SS”. This was achieved with a function called DD2DMSRead More
This (coordinate geometry – COGO) TSQL function creates a point geometry from a whole-circle bearing and distance.