Survey Database Settings Dialog Box

Use this dialog box to modify the survey database settings. These settings are specifically for the survey database features. By default, the survey database settings are stored in C:\Users\Public\Documents\Autodesk\Civil 3D Projects\<database name>\Survey.sdb_set file.

Units

Establish specify the database units.

Coordinate Zone: Click to display the Select Coordinate Zone dialog box where you can specify the coordinate zone for the survey database data. The default zone is set to None.
Distance: Specifies the distance unit. Click the cell in Value column and select a distance unit from the list.

Note: If you specify a Coordinate Zone, the distance unit is obtained from the zone and the Distance property field is not active.
Angle: Specifies the angle unit for the survey database data. Click the cell in the Value column and select an angle type from the list.
Direction: Specifies the direction type for the Survey database data. Click the cell in the Value column and select a direction type from the list.
Temperature: Specifies the temperature unit for the survey database data when temperature corrections are applied to observations. Click the cell in the Value column and select a temperature type from the list.
Pressure: Specifies the atmospheric pressure unit for the survey database when pressure corrections are applied to observations. Click the cell in the Value column and select a pressure type from the list.

Precision

Establish the display precision of the survey data.

Note: These precision settings are independent of the Drawing Settings precision settings. These settings affect all aspects of the user interface that displays survey data.

Angle: Specifies the precision value for all angle (including direction) values. The default precision is 4.
Distance: Specifies the precision value for all distance values. The default precision for Meters is 3, the default precision for Feet is 2.
Level: Specifies the precision value for all level values. The default precision for Meters is 3 and Feet is 2.
Coordinate: Specifies the precision value for all coordinate values. The default precision is 4.
Latitude and Longitude: Specifies the precision value for all latitude and longitude values. The default precision is 8.

Measurement Type Defaults

Establish the default types assigned to the measurements.

Note: For more information about the measurement types, see the Setting Measurement Type Defaults.

Angle Type: Specifies the default angle type. Click the cell in the Value column and select a distance type from the list.
Distance Type: Specifies the default distance type. Click the cell in the Value column and select a distance type from the list.
Vertical Type: Specifies the default vertical type. Click the cell in the Value column and select a vertical type from the list.
Target Type: Specifies the default target type. Click the cell in the Value column and select a target type from the list.

Measurement Corrections

Specify the default measurement corrections to apply to the survey observations.

Note: For information on formulas used to calculate corrections, see Setting Measurement Corrections.

Curvature and Refraction: Select Yes to correct measurement calculations for curvature of the earth and refraction of the sun light.
Sea Level: Select Yes to correct measurement calculations to sea level.
Atmospheric Conditions: Select Yes to correct measurement calculations for temperature and pressure.
Horizontal Collimation: Select Yes to correct Face 1 Angle and Face 2 Angle types for horizontal collimation .
Vertical Collimation: Select Yes to correct Face 1 Angle and Face 2 Angle types for vertical collimation.
Scale Factor: Select Yes to correct calculated horizontal distances for scale factor.
EDM-Prism Eccentricity: Select Yes to correct distance measurements for EDM and prism offsets.

Traverse Analysis Defaults

Do Traverse Analysis

Select Yes to perform a mathematical analysis based on the method you specify as the Horizontal Adjustment Method.

Do Angle Balance

Select Yes to have the angular error evenly distributed throughout the traverse.

Horizontal Adjustment Method

Specify one of the following traverse analysis methods:

Compass Rule: A method of corrections where the closing errors are assumed to be as much due to errors in observed angles as by the errors in measured distances. The closing errors in latitude and departure are distributed according to the ratio of the length of the line to the total length of the traverse.
Transit Rule: A method of balancing a traverse where the closing errors are assumed to be caused less by the errors in the observed angles than by the errors in measured distance. Corrections are distributed according to the ratio of the latitude and departure of each leg of the traverse to the sums of the latitude and departures of the entire traverse.
Crandall Rule: A method of balancing a traverse where all the angular error is distributed throughout the traverse and all adjustments to the traverse are due to modifying the traverse distances. The modification distance made to each leg is such that the sum of the squares is a minimum. Corrections corresponding to the closing errors assume that the closing errors are random and normally distributed and that all the angular error has been adjusted prior to the adjustment routine.
Least Squares: A method of balancing a traverse. The squares of the differences between the unadjusted and adjusted measurements (angles and distances) are summed and reduced to a minimum. This method weights the individual measurements according to the specifications set in the Equipment correction settings to determine the source of error. You can adjust the data for an individual traverse loop, or a traverse network, if located from multiple observations.

Vertical Adjustment Method

Specify one of the following vertical adjustment methods:

None: No vertical adjustment performed.
Length Weighted Distribution: Vertical adjustment distributes the vertical closing error to each line at the same ratio as the length of the line to the total length of the traverse (similar to the Compass rule).
Equal Distribution: Vertical adjustment distributes the vertical closing error equally to each of the traverse chainages.
Least Squares: A method of distributing the vertical error throughout a traverse. The squares of the differences between the unadjusted and adjusted measurements (angles and distances) are summed and reduced to a minimum. This method weights the individual measurements according to the specifications set in the Equipment correction settings to determine the source of error. You can adjust the data for an individual traverse loop, or a traverse network, if located from multiple observations.

Note: The Least Squares vertical adjustment method is only available if Least Squares has been selected as the horizontal adjustment method. When this method is selected, a 3D least squares adjustment is performed. If this method is not selected a 2D least squares adjustment is performed.

Horizontal Closure Limit 1:X

Specifies the minimum allowable error of closure in the horizontal direction, for example a value of 15000.00 is 1 part in 15000.

Vertical Closure Limit 1:X

Specifies the minimum allowable error of closure in the vertical direction, for example a value of 15000.00 is 1 part in 15000.

Angle Error Per Set

Specifics the maximum angular error per traverse observation set.

Least Squares Analysis Defaults

Specify the survey database setting defaults for performing a least square analysis on a network or a traverse.

Network Adjustment Type

Specifies the adjustment type for network least squares analysis only. The Traverse Analysis Defaults settings determine either a 2D or 3D analysis. Click the cell in the Value column and select one of the following from the list:

2-Dimensional: Sets the adjustment type to 2D. No adjustments are made to levels. Adjustments are only made to horizontal positions.
3-Dimensional: Sets the adjustment type to 3D. Adjustments are made to both horizontal and vertical positions.

Maximum Number of Iterations

Specifies the maximum number of times the least squares routine adjusts the observations before a solution is reached. This default setting is 8. The maximum number of iterations that you can enter is 10. Generally, the solution is reached within two or three iterations.

Coordinate Convergence

Specifies the maximum difference that is allowed between the coordinates before the solution is accepted.

Confidence Level

Specifies either 95% or 99% as the percentages calculated in conjunction with the F distribution. F is the ratio of two independent chi square variables, which are divided by the respective degrees of freedom. For example, if the confidence level is set to 99%, then you can be 99% sure that the calculated ellipse contains the true location for the point.

Perform Blunder Detection

Select Yes to include blunder detection in the least squares output (*.lso) file.

Survey Command Window

Specify the survey database settings for interacting with the Survey Command Window.

Ditto Feature

Select Yes to automatically repeat the last command in the Survey Command Window. This setting is on by default. When this setting is on, you can enter the command name once, and then continue to use the command by entering numeric data. To end the command, enter another command name.

Auto Point Numbering

Select Yes to enable automatic point numbering. When automatic point numbering is on, new points are automatically assigned the next available point number. When automatic point numbering is off, you must specify new point numbers as they are needed.

Start Point Numbering From

Specifies the number at which to start Auto Point Numbering.

Point Course Echo

Select Yes to have the Survey Command Window report the course taken to reach a point, including the direction and the distance.