2.3 Tags <gama-local> and <network>

A pair tag <gama-local> contains a single pair tag <network> that contains the network definition. The definition of the network is composed of three sections:

• <description> of the network (annotation or comments),
• network <parameters /> and
• <points-observations> section.

The sections <description> and <parameters /> are optional, the section <points-observations> is mandatory. These three sections may be presented in any order and may be repeated several times (in such a case, the corresponding sections are linked together by the software).

The pair tag <network> has two optional attributes axes-xy and angles. These attributes are used to describe orientation of the xy orthogonal coordinate system axes and the orientation of the observed angles and/or directions.

• axes-xy="ne" orientation of axes x and y; value ne implies that axis x is oriented north and axis y is oriented east. Acceptable values are ne, sw, es, wn for left-handed coordinate systems and en, nw, se, ws for right-handed coordinate systems (default value is ne).
• angles="right-handed" defines counterclockwise observed angles and/or directions, value left-handed defines clockwise observed angles and/or directions (default value is left-handed).

Many geodetic systems are right handed with x axis oriented east, y axis oriented north and counterclockwise angular observations. Example of left-handed orthogonal system with different axes orientation is coordinate system Krovak used in the Czech Republic where the axes x and y are oriented south and west respectively.

GNU Gama can adjust any combination of coordinate and angular systems.

Example

<gama-local>
<network>
   <description> ... </description>
   <parameters ... />
   <points-observations> ... </points-observations>
</network>
</gama-local>

It is planned in future versions of the program to allow more <network> tags (analysis of deformations etc.) and definitions of new tags.

This document was generated on February 17, 2024 using texi2html 1.82.