Time Matching is a feature in McIDAS-V that allows you to easily create loops of various data with differing temporal frequencies. An example case of where time matching may come in handy is if you want to create a 4-hour loop of satellite data, and overlay radar data on the satellite images. This data may come in with different frequencies (ex: Satellite data may come in 2 times an hour, while Radar data may come in 8 times an hour), and you only want to have 1 time step in the loop for each satellite image so the images do not repeat. In the past, a user would have to go into the Absolute Times tab of the radar data and individually select out every time that matched up with the satellite data. With Time Matching, you no longer need to do this. See the example image below:
The example above shows the temporal frequency that Satellite and Radar images come in (each image is marked by an 'X'). In this example, the Satellite data is set as the driver, and Radar data is set to be the slave to the driver. When using Time Matching, McIDAS-V will look at the time of the satellite image, and pick out the radar image that matches up most closely with each satellite time. This radar time may be earlier or later than the satellite time. In this example, only the satellite and radar times contained in the rectangles are used in the display. Therefore, every satellite image is used, but only every fourth radar image is displayed.
Time Matching can be used with a variety of types of data, including Satellite, Radar, Grid, and Point data. In general, the item with the lowest temporal frequency will be set as the "time driver", while other items will be set as a "slave" to the driver.
You can also set your time driver in the Time Animation Widget. There is an option in the Define Animation Times tab called Set as Time Driver. This feature allows you to set a block of times to be a driver before you load in any data. For example, you can set up a time animation over the last 5 hours in 30 minute increments, set this as the driver, and all slaves to the driver will utilize these times.