McIDAS User's Guide
Version 2019.1

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IMGTRACK

Redisplays a loop of images centered at a selected feature.


Format

IMGTRACK [keyword]


Keywords

MAG=

lmag emag

line and element magnification factors to use when the images are redisplayed; see the Remarks (default=1 lmag)

TRACKing=

YES

tracks image if allowed by the server; tracking allows commands to receive data as it's being ingested by the server; commands complete when their data request has been fulfilled; tracking is only supported on some servers (e.g., Area, GVAR and MTSAT) and it can be disabled by the server administrator

 

NO

does not track image so server only sends data that is currently available (default=value of MCTRACK environment variable; if MCTRACK is not set, default=value set by server or server administrator)


Remarks

IMGTRACK marks a feature on each frame of a loop set with the LS or LB command, then it uses the IMGDISP command to redisplay the images with the feature at the center of each frame. Use IMGTRACK to show a Lagrangian display of a moving feature.

The MAG keyword is used to increase or decrease the resolution when the images are redisplayed. The factors specified in MAG are relative to the originally-displayed image's resolution, not the image file's resolution. Thus MAG keyword values greater than 1 produce a blowup of the displayed image, and values less than 0 produce a blowdown. MAG=1 (the default) redisplays at the same resolution.

The keyword TRACKING= has a different meaning that the command name. The keyword refers to requesting whether the server sends only the data that was available when the command was issued (tracking=no), or to wait until all of the requested data is available before completing the request (tracking=yes). The "track" in the command name refers to tracking a feature on a loop of images and redisplaying them so that the feature appears at the center of each frame.


Examples

IMGTRACK

This entry prompts you to step through each frame of the current loop, marking the desired feature by moving the cursor to the feature's location and pressing the middle mouse button. When you've stepped through all the frames in the loop, press Alt G to redisplay the images with the feature at the center of each frame. Then press Alt Q or the center and right mouse buttons to exit the program.

IMGTRACK MAG=3 2

This entry is the same as the one above, except that it uses a line blowup factor of three and an element blowup factor of two when redisplaying the images.


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