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What is the difference between points and stations?
In MDT, the distinction between points and stations (also frequently referred to as bases) is fundamental for processing topographic data, differing mainly in their function within the survey and their method of identification:
Function and Definition
Stations (or Bases): They represent the positioning or setup points of the instrument (total station) from which observations begin. They are the vertices that make up the control structure of the work, such as station observations or networks.
Points: These are the fill or detail elements measured from a station to define the morphology of the terrain or specific elements of the project.
Identification and Observations
Station Observations: They are identified by their origin station, the I. Height (the positioning), and the name of the sighted base. These observations can be "forward" or "forward and back" (reciprocal) types for the calculation of networks and traverses.
Point Observations: Conversely, they are identified solely by their ordinal point number. When importing data, MDT usually distinguishes points from stations based on criteria such as code, prefixes, or numerical intervals.
Stored Information
Station Attributes: In addition to X, Y, Z coordinates, stations can store advanced technical information such as scale or anamorphosis, and are classified as fixed (which do not vary their position in the calculation) or mobile.
Point Attributes: They basically store their number, coordinates, and a descriptive code. However, if taken with specific instruments, they may include additional data such as measurement uncertainty or hyperlinks.
Graphical Representation
Stations: The Draw Stations command represents them using blocks with attributes. Fixed bases are usually drawn as a triangle and mobile ones as a circle.
Points: The DRAW POINTS command represents them with their standard symbology, usually showing the point number, elevation (Z), and the associated code.
Conversion
The software allows interoperability between both entities:
It is possible to Convert Stations to Points (for example, when a read station is desired to be treated as just another fill point).
You can also Convert Points to Stations, automatically assigning them a name composed of a "P" followed by their original number, so they can be used as reference bases or new setups.