Two types of text files can be created that will log data measurements:
Data Log File: This file is a running log of measurements. These measurements can be made in real time or from captured movies. In general, it will contain data from many experiments or movies.
Each entry has the date and time stamp of the movie. New data is appended to the end of the file. You control what data is written by your choice of graph plotting. The contents of the Y (left hand) and Y2 (right hand) graph axes are stored in the data log. This limits the entry to, at most, two data types. If a movie contains more than one image, there will be one line in the data log for each analyzed image. This is exactly like the graph and the data grid from which the graph is drawn. The data log is updated when the movie is closed, so the choices that are present then govern what is in the log. If you simply open a movie and do not analyze anything, no addition is made to the data log. You must analyze something to make an addition. If this movie has been previously opened, the previous entries are unchanged.
The format for each data line in the data log is
* Date and time stamp of movie, set when the movie originally acquired
* Graph time for this image; always 0 for SnapShots
* Y axis data, a single number; blank if no data
* Y2 axis data, a single number; blank if no data
The data log is updated if the Autolog checkbox is checked on the Log-On screen or if the user answers Yes when opening a new data log file from the main File menu. The main File menu allows you to change the name of the current data log file. The current data log file name is shown in the Log-On drop down list and may be changed there also.
Statistics are computed for the overall data set contained in the Y and Y2 axes. These are useful only if the same data type is present for each entry of the individual axis. The user is responsible for this if they wish to make use of the statistics. The values reported for each axis are
* Number of entries
* Mean or average of the set
* Population standard deviation (divided by N-1 rather than N)
Movie Log File: Each movie can have its own separate, and complete, data. This data log is an exact copy of the data grid on the Graph | Data tab, so everything that is measured is available in this log file. The file is created when the Movie is closed if Autolog is checked on the Log-On screen. It has the same name as the movie except that the extension is "txt" rather than "mdb". You can not assign an entirely different name to the Movie data log.
Both types of log files can be easily imported into Excel.
All text data logs have a choice of using a tab or a comma as the separator between numbers or fields. Choose which is best based on how you represent numbers and what you intend to do with the data. Many programs prefer a tab.
Some of the features described above were added in Builds 148 and 149 of 2.0.