2.10 Horizontal distances

Distances are written using an empty-element tag <distance /> with attributes

• from = "..." standpoint identification
• to = "..." target identification
• val = "..." observed horizontal distance
• stdev = "..." standard deviation of observed horizontal distance (optional)
• from_dh = "..." instrument height (optional)
• to_dh = "..." reflector/target height (optional)

Contrary to directions, distances in an observation set (<obs>) do not need to share a common stand-point. An example is set of distances observed from several stand-points with a common variance-covariance matrix.

Example

     <distance from = "2"  to = "1" val = "659.184" />
     <distance to ="422" val="228.207"  stdev="5.0"  />
     <distance to ="408" val="568.341" />