## GeoLab Options Overview

GeoLab project options settings are controlled by special options files. The Options dialog provides a systematic interface that allows you to easily edit the various options settings. This dialog consists of five tabbed pages (Drawing, Adjustment, Statistics, Output Configuration, and Output Composition) as discussed below. |

**Drawing Page**

This page contains controls that pertain to GeoLab's network drawing. It contains the following:

**Network Drawing Attributes Group**: This group contains controls that allow you to choose how GeoLab should draw adjusted networks. The controls are as follows:**Items List**: This list contains the names of all items that GeoLab draws when drawing a network. Other controls in this group display the settings for the currently selected item in this list.**Line Type List**: This list displays all line types that GeoLab uses to draw lines, and allows you to select the line type for the currently selected item in the Items List.**Color List**: This list displays all colors that GeoLab uses to draw items, and allows you to select the color for the currently selected item in the Items List.**Draw Selected Item Check**: This checkbox controls whether the currently selected item in the Items List is drawn. If checked, the item will be drawn; if not checked, the item will not be drawn.**Draw All Button**: This button turns drawing on for all items in the Items List.**Draw None Button**: This button turns drawing off for all items in the Items List.

**Draw Connections Group**: This group contains radio buttons that control which lines GeoLab will draw between stations in a network drawing. The selections are as follows:**Observed Lines**: Draw only lines for which there are observations.**All Lines**: Draw all lines.

**Scrolling Group**: This group contains drop-down lists that control the amounts that a network drawing is scrolled by scroll bar operations. Both of the following values are percentages of the drawing size:**Line Up/Down**: The amount to scroll when a line up or line down scroll bar operation is made.**Page Up/Down**: The amount to scroll when a page up or page down scroll bar operation is made.

**Grid Spacing (DMS) Group**: The controls in this group specify default grid spacing values used for drawing the latitude/longitude grid lines in a network drawing. The two values are as follows:**Latitude**: The default grid spacing (in degrees, minutes, and seconds) for latitudes.**Longitude**: The default grid spacing (in degrees, minutes, and seconds) for longitudes.

## Adjustment Page

This page contains controls that pertain to processing survey networks with GeoLab. It contains the following:

**Computation Type Group**: This group contains the following two radio buttons:**Adjustment**: GeoLab will perform a network adjustment.**Simulation**: GeoLab will perform a network simulation (preanalysis).

**Computation Options Group**: This group contains the following checkboxes:**Generate Initial Coordinates**: If this is checked, GeoLab will generate initial coordinates for all network stations. If it is not checked, coordinate generation will not be performed.**Optimize Band Width**: If this is checked, GeoLab will reorder the parameters in the normal equations to arrive at a minimum variable bandwidth (to speed adjustment computations). If it is not checked, no reordering will be performed.**Compute Full Inverse**: If this is checked, GeoLab will compute the entire parameter covariance matrix. If it is not checked, only the portions of the parameter covariance matrix that correspond to stations connected by observations will be computed.**Force Convergence**: If this is checked, GeoLab will consider that the adjustment has converged (even if it has not) when the specified maximum number adjustment iterations is reached. If it is not checked, the adjustment computation will be aborted when convergence is not reached in the specified maximum number adjustment iterations.**Distances Contribute to Heights**: If this is checked, GeoLab will use a 3D observation equation for spatial distance measurements, thereby allowing these measurements to contribute to the determination of network heights. If it is not checked, the usual 2D observation equation will be used.**Perform Orthometric Corrections**: If this is checked, GeoLab will make orthometric corrections to observed orthometric height differences (OHDF records). If it is not checked, orthometric corrections will not be made.**Re-Transform Obs After 1st Pass**: If this is checked, GeoLab will re-transform 2D coordinate observations to their 3D counterparts before each adjustment iteration (to remove any inconsistencies caused by inaccurate initial coordinates). If it is not checked, these re-transformations will not be made.

**Convergence Criterion Edit Box**: This edit box is used to specify the convergence criterion for adjustments.**Maximum Matrix RAM Edit Box**: This edit box specifies how much system memory GeoLab can use for each matrix. As a rule of thumb, you should not specify more than about one-quarter of system memory for each matrix. The higher the value you set, the more likely that GeoLab will do all computations in system memory, and if all computations are performed in system memory, the time to perform even large adjustments will be greatly reduced.**Observation Angle Unit List**: This list is used to select the units (either degrees, minutes, seconds, or grads) for angle-type observations.**Maximum Iterations List**: This list is used to select the maximum number of iterations that GeoLab will perform when performing an adjustment.**Maximum Errors List**: This list is used to select the maximum number of errors that GeoLab will allow before aborting an adjustment or simulation.**Geoid Interpolation Method List**: This list is used to select the method for interpolating geoid files between grid intersections. Each geoid interpolation method uses a simple polynomial for the geoid undulation in latitude and longitude increments. The methods currently supported by GeoLab are as follows:**Bi-Linear**: Max. Power = 1; Number of Terms = 4**Bi-Quadratic**: Max. Power = 2; Number of Terms = 9**Bi-Cubic**: Max. Power = 3, Number of Terms = 16**Bi-Quartic**: Max. Power = 4, Number of Terms = 25

**Default Linear Unit List**: This list allows you to select the default linear unit for network processing.**Default Ellipsoid List**: This list allows you to select the default reference ellipsoid for network processing.## Statistics Page

This page contains controls that pertain to statistical tests and confidence regions. It contains the following controls:

**Ignore observation standard deviation when a sigma record is used check box**: If this checkbox is checked, the observation standard deviation on an observation record will not be used in computing the observation's standard deviation (only the SIGM record's values will be used. If it is not checked, the observation standard deviation on the observation record will be used, in addition to the values on the SIGM record, to compute the observation's standard deviation.**Variance Factor Group Box**: This group of variables specifies how the variance factor is used in performing adjustments with GeoLab. Please refer to Geodesy The Concepts, by Vanicek & Krakiwsky (1982), Chapter 13, for details on the significance of these selections. This group box contains the following check boxes:**Known**: If this box is checked (as it should normally be), GeoLab will perform adjustment statistics assuming the variance factor is known. If it is not checked, the statistics will be performed assuming the variance factor is unknown.**Scale Covariance Matrix**: If this box is checked, GeoLab will multiply the parameter covariance matrix by the estimated variance factor. If it is not checked, this scaling will not be done.**Scale Residual Variances**: If this box is checked, GeoLab will multiply the residual variances by the estimated variance factor. If it is not checked, this scaling will not be done.

**Compute Confidence Regions Group Box**: This group box contains the following check boxes:**Point**: If this box is checked, GeoLab will produce point confidence regions when performing an adjustment or simulation (note that you must have at least one of the Vertical, Horizontal, and 3D check boxes checked for this checkbox to be enabled).**Vertical**: If this box is checked, GeoLab will produce point (if the Point checkbox is checked) and relative vertical confidence regions when performing an adjustment or simulation.**Horizontal**: If this box is checked, GeoLab will produce point (if the Point checkbox is checked) and relative horizontal confidence regions (error ellipses) when performing an adjustment or simulation.**3D**: If this box is checked, GeoLab will produce point (if the Point checkbox is checked) and relative three-dimensional confidence regions when performing an adjustment or simulation.

**Confidence Levels (10.0 - 99.999 percent) Group Box:**This group box is used to select confidence levels used for statistics when GeoLab performs an adjustment or simulation. It contains the following edit boxes:**Residuals & Net Diffs**: Level for testing residuals and for testing the significance of network differences.**1D Confidence Regions**: Level used for determining the expansion factor for one dimensional regions.**2D Confidence Regions**: Level used for determining the expansion factor for two dimensional regions.**3D Confidence Regions**: Level used for determining the expansion factor for three dimensional regions.

**Residual Rejection Type List Box**: This list box is used to select the type of criterion to be used by GeoLab when determining whether residuals are to be rejected.**Misclosure Flagging Factors Group Box**: This group box contains two edit controls for specifying factors to be used when GeoLab decides whether to flag a misclosure as large enough to be flagged as a potential problem. If the misclosure is larger than the observation standard deviation times the factor, the observation will be flagged) The edit boxes are as follows:**Linear**: The factor for linear-type observations.**Angular**: The factor for angular-type observations.

## Output Configuration Page

This page contains controls that pertain to the format of the output listing that GeoLab produces when performing an adjustment or simulation. It contains the following controls:

**Output Decimal Places Group Box**: The controls in this group box specify the numbers of decimal places that GeoLab will use in writing values to the output listing as follows:**Angular Observations**: The number of decimal places for writing angular observation types.**Linear Observations**: The number of decimal places for writing linear observation types.**Latitudes/Longitudes**: The number of decimal places for writing latitudes and longitudes.**Rotations in Seconds**: The number of decimal places for displaying 4-parameter and 7-parameter rotation values.**Scales in PPM**: The number of decimal places for displaying 4-parameter and 7-parameter scale values.**Map Projection Scales**: The number of decimal places for displaying map projection origin scale values.

**Output Options Group Box**: The controls in this group box specify adjustment output options as follows:**Show West Longitudes**: This option controls the display and printing format for longitudes. If not checked, longitudes will always be printed as east-longitudes (0-359), otherwise west-longitudes will be displayed and printed for points in the western hemisphere.**Print 3D Residuals as N, E, Up**: If checked, residuals for 3D coordinate and coordinate difference observations will be printed as values in the north, east, and up directions; if not checked, residuals for these observations will be printed as values in the directions of the geocentric Cartesian axes.**Print Canadian Order**: If checked, the Canadian order designation (Geodetic Survey of Canada 1973 Specifications) for the least accurate relative error ellipse will be printed.**Report Unrecognized Errors**: If checked, GeoLab will write a warning in the output listing when a non-blank unrecognized text record is encountered in the input text file.**Do Chi-Square Test**: If checked, GeoLab will write a summary of the adjustment's chi-square test on the variance factor to the output listing.

## Output Composition Page

This page contains controls that pertain to the contents of an output listing that GeoLab produces when performing an adjustment or simulation. It contains the following controls:

**Print Input Values Group Box**: The "Station Data" control in this group box, if checked, results in writing input station data to the output listing.**Print Adjusted Values Group Box**: The controls in this group box select which adjusted information is written to the output listing as follows:- NEO Values: If checked, NEO records containing adjusted values are written.
- NEH Values: If checked, NEH records containing adjusted values are written.
- PLH Values: If checked, PLH records containing adjusted values are written.
- PLO Values: If checked, PLO records containing adjusted values are written.
- XYZ Values: If checked, XYZ records containing adjusted values are written.
- Auxiliary Parameter Values (AUX): If checked, adjusted auxiliary parameter values are written
- Scale & Convergence Values (SFMC): If checked, point scale and meridian convergence values are written if the NEO or NEH Values are checked.
- Grid Distances and Azimuths: If checked, grid distances, grid azimuths, and combined scale factors are written if one or more map projections are used. The Connected Only (by observations) and All Lines radio buttons allow you to select which lines to list this information for.

**Print Adjustment Solution Group Box**: The controls in this group box select whether adjustment solutions (adjustment corrections to the parameters) are written during adjustment iterations as follows:**Enable**: If checked, the solution is written for the first pass of the adjustment; if not checked, no solution is written (even if the following check box is checked)**All Passes (not only the first pass)**: If checked, solutions are written for all passes of the adjustment (but only if the previous check box is checked).

**Print Misclosures Group Box**: The controls in this group box determine whether adjustment misclosures are written during adjustment iterations as follows:**First Pass**: If checked, misclosures are written for the first pass of the adjustment.**Subsequent Passes**: If checked, misclosures are written for all passes of the adjustment.

**Print Residuals Group Box**: The controls in this group box determine whether adjustment residuals are written as follows:**Enable**: If checked, residuals are written.**Rejects Only**: If checked (and if Enable is checked), only residuals flagged for rejection are written.

**Print Geoid Values Group Box**: The control in this group box determines whether geoid values are written for each network station as follows: If**Enable**is checked, geoid values are written.**Print Relative Confidence Regions Group Box**: The controls in this group box determine whether, and which, relative confidence regions are written as follows:**None**: If checked, no confidence regions are written.**Which Group Box**: If None is not checked, the controls in this check box determine which confidence regions to write as follows:**All**: All confidence regions;**Connected**: Only confidence regions for lines that have observations;**Within Radius**: Only confidence regions for lines not greater in length than the radius specified in Radius (km);**Radius**(km): The radius for the Within Radius option.

**Note**: When the All option is selected, you can select only the stations for which you want relative confidence regions by creating a text file with the same path and name as the IOB file for the project, and with extension ".crs". Each line of this text file must contain the name of each selected station.