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merge noao.imred.vtel



merge -- Merge together daily synoptic grams into a complete Carrington map


merge outimage outweight outabs outratio month day year


Name of output image.
Output image containing weights, number of pixels per pixel.
Output image containing the sums of the absolute values of the flux. Not used when merging 10830 maps.
Output image containing the ratio of outimage/outabs. Not used when merging 10830 maps.
month, day, year
Date of the center of this Carrington rotation.
longout = 180
Longitude of the center of this Carrington rotation.
mergelist = "mergelist"
File containing list of files to be merged.


Merge adds up daily synoptic grams to produce a Carrington rotation map. the input images are 180x180 and the output images are 360x180. The input images are read from the file mergelist. Merge then weights the input image as cos**4 in x where the center of the image corresponds to zero angle and the left and right edges of the image correspond to -90 and +90 degrees respectively. The input image consists of an unweighted "data" image, a weight image, and an absolute value image. The summing is done on the "data" image, on the weight image, and on the absolute value image separately to produce three output images. Finally the "data" image is divided by the absolute value image to produce a 4th output image. If 10830 data is being merged there are only two(2) images per day, the "data" image and the "weight" image. Also there are only two(2) output images, the "data" merged image and the "weights" merged image. A note about the mergelist file, the three grams for each day must be stored in the following sequence (data, absolute value, weight) for magnetograms and the two grams for each day must be stored as (data, weight) for 10830. The filenames must be one file name per line in the mergelist and files for different days must be grouped together, for example mergelist might look like:

	MAG01                                  MAG01
	MAG01a                                 MAG01w
	MAG01w     for magnetograms or         MAG02      for 10830 grams
	MAG02                                  MAG02w

for merging only two days of data where the first day is MAG01 and the second is MAG02. The a extension stands for absolute value and the w for weights.


1. To merge a number of images on disk into output images called "im", "imweight", "imabs", and "imratio", where the date corresponding to the center of the Carrington map is 3/20/84 the command would be (magnetograms):

	vt> merge im imweight imabs imratio 3 20 84

The same command used for 10830 grams would be:

	vt> merge im imweight 3 20 84

2. If you have the list of files to be merged listed in a file called "mlist" instead of "mergelist" the command would be modified to read:

	vt> merge im imweight 3 20 84 mergelist="mlist"


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