Wintrack

Surface statement

 Surface
   Tgt=Snn
   [Field=field_name]
   [Xres=xx]
   [Yres=yy]
   [Range=trial_range]
   [Goal=NO|NE|NW|SE|SW|NEF|NWF|SEF|SWF]
   [Crit=seconds]
   [Sint=sampling_interval]
   Mode=Ave|Zave|Sum|Zsum|Ratio|Min|MinMax|Count|Ref|Stereo|Predict|Path

Type conventions and statement syntax are explained in the Glossary.

Computes a data surface using xy-coordinates, time stamps, and, depending on the specified Mode, the data in the active data matrix. Each cell of the data surface stands for a rectangular tile inside the arena or a specified field of reference. The arrangement of the cells in the data surface in columns and rows represents the arrangement of the tiles in the x- and y-dimension, respectively. As needed, cell values of the active data matrix are mapped onto cells of the data surface using the x- and y-position coordinates of the data points. Wintrack can store up to 5 data surfaces at a time. In each of them, the individual trials are represented as a stack of separate planes.

Parameters...

Tgt
Name parameter indicating the target data surface. Valid surface names are S1 through S5. There is no default for this parameter.

Field
Name parameter specifying the name of a field defined in the currently loaded setup and serving as reference frame for the surfacae. Only points located inside the reference frame are considered for the surface calculation. Tthe whole arena is used as reference frame if this parameter is omitted.

Xres
Number parameter indicating the number of rectangular tiles to be used to fill the reference field horizontally. Valid values are 2 through 256. Default is 10.

Yres
Number parameter indicating the number of rectangular tiles to be used to fill the reference field vertically. Valid values are 2 through 256. Default is 10.

Range
Range parameter indicating the range of trials to be considered. This optional parameter can be used to save time by suppressing calculation of trials whose data will not be of interest during later stages of analysis. By default, all trials are processed.

Goal
Name parameter indicating the name of the goal position to which the data surface will is to be normalized by rotation of individual trials. NE = Northeast, NW = Northwest, SE = Southeast, SW = Southwest, NO = no normalization. NEF, NWF, SEF, SWF are treated as NE, NW, SE, SW, respectively, except that any rotation by 90° is replaced by a horizontal flip and and any rotation by -90° is replaced by a vertical flip. Default is NO. Normalization should not be used with case documents that lack goal information.

Crit
Number parameter indicating the minimal amount of time in seconds the subject must spend inside a tile for it to be counted as a visit. Data points not meeting this criterion will be assigned to the next visited tile. Default is 0.

Sint
Number parameter indicating the sampling interval. Defines how tile of origin is determined if Mode is set to Predict or Path. Default is 0.

Mode
Radio button parameter indicating the computation mode and data transformation to be applied. There is no default for this parameter, specify one of the following options:

Ave = average of all data matrix cell values assigned to the respective tile of the data surface. Cells that represent tiles which were not assigned any data points remain empty.

Zave = same as Ave, but a z-transformation is applied to the cell values of the data surface before cell values of individual trials are averaged.

Sum = sum of all data matrix cell values assigned to the respective tile of the data surface. Cells that represent tiles which were not assigned any data points are set 0. Cells that represent tiles not overlapping a round arena remain empty.

Zsum = same as Sum, but a z-transformation is applied to the cell values of the data surface before cell values of individual trials are averaged.

Ratio = same as Sum, but all cell values of the data surface are divided by the cell value expected if data were evenly distributed across the arena, that is a observed/chance ratio is computed. This division is performed before cell values of individual trials are averaged.

Min =minimum of all data matrix cell values assigned to the respective tile of the data surface. Cells that represent tiles which were not hit by any data points remain empty.

MinMax = same as Min, but cells that represent tiles which were not hit by any data points are padded with the overall largest value in the data matrix. Cells that represent tiles not overlapping a round arena remain empty.

Count = count visits to each tile. Cells that represent tiles not overlapping a round arena remain empty. This mode does not use the current data matrix.

Ref = set tile value =1 if the tile overlaps with the arena. Cells that represent tiles which do not overlap with the arena remain empty. This mode is useful to determine how many corner tiles lie outside a round arena. It does not use the current data matrix.

Stereo = determine stereotypy count for each tile. The sequence of tile visits is scanned for repeated patterns. Each repetition increments the stereotypy count of all involved tiles. This mode does not use the current data matrix.

Predict = predictability index for each tile. 1 if all visits to that tile originate from the same tile. 0 if origins of visits are randomly distributed or if tile was visited only once. The tile of origin of each visit is determined based on the specified sampling interval. For Sint = 1 it is the last visited tile, for Sint = 2 it is the second last visited tile, etc. This mode does not use the current data matrix.

Path = cumulative distance to tiles of origin of all visits to the tile in question. The tile of origin of each visit is determined based on the specified sampling interval. For Sint = 1 it is the last visited tile, for Sint = 2 it is the second last visited tile, etc. This mode does not use the current data matrix.

Note that...

In order to be considered for the computation of a data surface, a trial must be part of the trial range specified in the Range parameter of the Surface statement. Once the custom variable definition file is processed by the Analyze Case command, Wintrack will also check the trial range specified in the Range parameter of that command. Computation will only consider trials which are part of that range too.

You must execute the Matrix statement at least once to create an active data matrix and build a selection mask using the Include and/or Exclude statements, before you can use the Surface statement. You can also use a Window statement to set a time window before computing the data surface. Computing a data surface does not affect the content of the current data matrix and considers only selected matrix cells. You can compute more than one data surface using the same data matrix by executing the Surface statement repeatedly. Once you have created data surfaces, you can use them as a source to create surface variables using the Tabulate statement, or to create data arrays using the Collect statement.

Additional information...

Managing custom variable definition files provides general information on the management of custom variable definition files.
The Flowchart of advanced data analysis gives a synopsis of data and variable types.
There is a topic describing how to build a custom variable definition file.
There is a list of all available variable definition statements.
Using the Memory statement you can build collections of data matrices and selection masks for later reuse in other variables.
See Analyze Case Document command for basic information on that command.
Inside case documents provides advanced information on case documents.