; IMTXT ;--------------------------------------------------------------- ;! Write an image to an external text file. ;# Task Imaging ;----------------------------------------------------------------------- ;; Copyright (C) 1995, 2008 ;; Associated Universities, Inc. Washington DC, USA. ;; ;; This program is free software; you can redistribute it and/or ;; modify it under the terms of the GNU General Public License as ;; published by the Free Software Foundation; either version 2 of ;; the License, or (at your option) any later version. ;; ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; ;; You should have received a copy of the GNU General Public ;; License along with this program; if not, write to the Free ;; Software Foundation, Inc., 675 Massachusetts Ave, Cambridge, ;; MA 02139, USA. ;; ;; Correspondence concerning AIPS should be addressed as follows: ;; Internet email: aipsmail@nrao.edu. ;; Postal address: AIPS Project Office ;; National Radio Astronomy Observatory ;; 520 Edgemont Road ;; Charlottesville, VA 22903-2475 USA ;----------------------------------------------------------------------- IMTXT LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC IMTXT Write an image to an external text file. INNAME Input image name (name) INCLASS Input image name (class) INSEQ -1.0 9999.0 Input image name (seq. #) INDISK 0.0 9.0 Input image disk unit #. BLC 0.0 4096.0 Bottom left corner of image 0=>entire image TRC 0.0 4096.0 Top right corner of image 0=>entire image FACTOR Multiplication factor. 0 => 1 TRANSCOD Fortran format (e.g. 'F5.1') X Value of blanked pixel. DATAOUT Output file name (Non-AIPS) ---------------------------------------------------------------- IMTXT Task: Write an image to an external text file. The format used is that used by FETCH in reading images. Each row in the image will be written to a single line in the output file and there is a limit of 1000 characters in a line in the output file Adverbs: INNAME.....Input image name (name). Standard behavior INCLASS....Input image name (class). Standard defaults. INSEQ......Input image name (seq. #). 0 => highest. INDISK.....Disk drive # of input image. 0 => highest number BLC........The bottom left-hand pixel of the input image which becomes the bottom left corner of the subimage. The value (0,0) means (1,1). TRC........The top right-hand pixel of the input image which becomes the top right corner of the subimage. The value (0,0) means take the top right hand corner of the image. FACTOR.....The pixel values will be multiplied by FACTOR before writing. 0 => 1.0 TRANSCOD...The Fortran format to be used. This format should be appropriate for a single value and will be replicated as necessary. NOTE: the format should NOT include the repeat count, this will be determined from the subimage size. An example is 'F10.5'. The appropriate format codes are 'F', 'E' and 'I'. X..........The value to be used for blanked pixels; this is the value to be written and is not multiplied by FACTOR. NOTE: this value must be kept exactly by the specified format, e.g., don't use -999.99 and TRANSCOD='I5'. DATAOUT....A file external to the AIPS system into which the image is to be written. --------------------------------------------------------------- IMTXT: Task writes an AIPS image to an external, formatted file. DOCUMENTOR: W. D. Cotton, NRAO. RELATED PORGRAMS: FETCH PURPOSE IMTXT converts a subimage of an AIPS image to an external text file. This file contains the information in a form that can be read by task FETCH. The pixel values are encoded one line per row in the image after possibly scaling using a specified Fortran format (TRANSCODE). Blanked pixels will be replaced by a specified value. All data from a row in the selected subimage must fit in a single line in the output image which may not exceed 1000 characters. The output file begins with a small amount of descriptive information. This is described below. COMMENTS DATAOUT: The user must specify a text file for the image. The header section of the output file contains a series of keyword-value pairs to define the image followed by the data in row order. The output file can be specified as follows shown in the following example: DATAOUT='myarea:image.dat' where MYAREA is an environment variable set before starting AIPS e.g.: %setenv MYAREA /mnt/username Note also: in UNIX all files whose names are passed to AIPS should have names containing only upper case characters. The header portion of the image file contains a number of keyword-value pairs: NAXIS = n (The number of axes in the image, up to 7 are allowed) DIM = m1, m2, ... (The dimension of each axis used.) FORMAT = 'r?w.d' (The FORTRAN format used to encode the pixel values; derived from TRANSCODE. OBJECT = 'name' (The name of the object) TELESCOP = 'name' (The name of the telescope used) INSTRUME ='name' (The instrument used) OBSERVER='name' (The observers name) UNITS = 'units' (The units of the image) EPOCH = xxxx.x (The mean Epoch of the coordinates) CRTYPE='a','b'... (The axis type (label) of each axis) CRVAL = x.x, y.y... (The coordinate values at the reference pixel on each axis, angles are in degrees.) CRINC = x.x, y.y ...(The increment in coordinate values between successive pixels. ) CRREF = x.x, y.y... (The reference pixel on each axis, need not be an integer.) CRROT = x.x, y.y... (The rotation; by convention the rotation angle on the sky is associated with the declination or latitude-like axis.) SCALE = x.x (A scale factor to be applied to the values read) OFFSET = y.y (An offset to be added to the values read after any scaling.) BLANK = b.b The blanked (undefined) value BEFORE any scaling and offset. The header section is terminated by a '/'. Following this is the data stored by row (first axis) with the other axes given with the lower numbered axes varying the fastest. ERROR CONDITIONS Most possible errors have more-or-less explanatory messages. However, if either a scaled pixel value blows the format or a line exceeds the maximum number (1000) of characters then the message: "ERROR WRITING OUTPUT TEXT LINE" will be issued and the task will die.