Month: July 2020

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

In working with circles or arc segments one needs to be able to do more than just calculate chordlengths, arclengths or arc2chord separations. For example, in order to be able to convert circles and arcs to vertex-stroked polygons and vice versa one needs to be able to compute the number of vertices to place betweenRead More

This SQL Server TSQL function returns a (Normalized) bearing in Degrees between two non-geodetic (XY) coordinates.

In working with circles (and circular arcs) in spatial data one must be able to compute the length of an arc defined by an angle subtended at the centre of a circle. In particular this is important for converting circles to vertex-stroked polygons and vice versa. Here is an encoding of the calculation of theRead More

In working with circles one must be able to compute the arc2chord separation, the length of an arc and the length of the chord subtended by an angle subtended at the centre of a circle. In particular this is important for converting circles to vertex-stroked polygons and vice versa. Here is an encoding of theRead More

Computing the arc to chord (Arc2Chord) separation between an arc on the circumference of a circle and the chord subtended by that arc is considered to be a vital measure for determining how well a vertex defined polygon matches its related circle (or arc in a circular arc). In cadastral applications, an arc to chordRead More

The relevant standards covering spatial data types within databases provide functionality at many levels (and miss some that is required by pratitioners like myself) from object definition through to API specification. One area within those standards that has limited support within commercial GIS software and database implementations is the case of circular arcs (line andRead More

Recently I had need to convert a PL/SQL Oracle Spatial function I created years ago called FindCircle to SQL Server 2008 for use in another project. That function was original work already released to the public domain as part of my free COGO package for Oracle. Here is that function for SQL Server. Note that IRead More