Survey / Filter survey vector
This is the first step in both of the workflows presented in the Chapter’s introduction. Filter survey vector command starts from the selected line string element. The filtering process modifies the line string in order to make it better suited for the task of creating geometry components. The goal is to get a line string that does not have vertices too close to each other or too far apart. In ideal case, this step would not be needed. However, since the application does not make any assumption on the source of the survey vector, this command is used to make sure that the input line string is reasonable.
To create a filtered survey vector
1. Select a line string element using CAD platform Selection tool.
2. Select Filter survey vector command from the Survey pulldown menu.
This opens the Filter survey vector dialog:
3. Define settings and click OK.
SETTING |
EFFECT |
|---|---|
Data noise level |
Controls, in part, how many points the application automatically adds to the line string using linear interpolation. •Typically, this parameter is Normal. •However, if there are gaps in the line string or the data is noisy, use High. •Value Low can be used if the component length is large compared to the average point distance and data is smooth. |
Min. component length |
Determines, together with Data noise level, how many points are added to the survey line string in the filtering process. The goal is to have approximately six points for each minimum component length. Typically, the value should be at maximum 0.5 * the known minimum component length. Larger values can cause the application to miss components which results in a poor-quality geometry. |
Point filtering step |
Defines the approximate minimum distance between the vertices in the filtered line string. For a line string with a large vertex density, the parameter can be used to filter out vertices and speed up the calculations. Typically, the value should be much smaller than the minimum component length, for example one sixth of the minimum component length. |
The filtered line string should not be modified since any changes to its position or shape is directly translated to the geometry components.
