i.tape.spot(1)		      Grass User's Manual		i.tape.spot(1)



NNAAMMEE
       ii..ttaappee..ssppoott   -	An  imagery  function  that extracts SPOT imagery from
       half-inch tape.
       _(_G_R_A_S_S _I_m_a_g_e _P_r_o_c_e_s_s_i_n_g _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       ii..ttaappee..ssppoott

DDEESSCCRRIIPPTTIIOONN
       _i_._t_a_p_e_._s_p_o_t is a program that extracts SPOT imagery from 9-track, half-
       inch tape.


       This program must be run in a LOCATION_NAME with an x,y coordinate sys-
       tem (i.e., a coordinate system with projection 0).  For further	infor-
       mation  regarding  this	LOCATION_NAME type refer to the _i_m_a_g_e_r_y manual
       entry.


       The first prompt in _i_._t_a_p_e_._s_p_o_t asks the user for the tape device name.
       Enter tape device name:

       This  is sometimes  /dev/rmt0 (for a half-inch tape having a density of
       1600 bpi), but this varies with each machine.


       The next prompt is:


       Mount SPOT tape and  hit RETURN


IIMMAAGGEE IIDDEENNTTIIFFIICCAATTIIOONN MMEENNUU
       The first menu in the program asks the user for information  about  the
       data.
	     Please enter the following information

       TAPE IDENTIFICATION:				__

       IMAGE DESCRIPTION:				__

       TITLE FOR THE EXTRACTED CELL (RASTER) FILES:	__

       AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
		     (OR <Ctrl-C> TO CANCEL)
	 This  program	automatically  reads  the satellite name, tape product
       code, instrument name, interleaving indicator, spectral	mode,  prepro-
       cessing level and work order number into the field for TAPE IDENTIFICA-
       TION.  The mission, path, row, scene shift, scene center date and time,
       orientation, incidence, azimuth, elevation angle, and absolute calibra-
       tion coefficients and offsets are automatically entered into the  field
       for  IMAGE  DESCRIPTION.   User can type in any other messages into the
       two sections and a description as the TITLE of raster map  layer.   The
       second menu is:
		       SPOT IMAGE EXTRACT
	   Please select region of the image to extract

		    start row: 0______(1-3002)
		      end row: 0______(1-3002)

		    start col: 0______(1-3166)
		      end col: 0______(1-3166)


       AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
		     (OR <Ctrl-C> TO CANCEL)
	The numbers in parentheses are the total number of rows and columns on
       the tape including zeros (filler).   This  information  and  additional
       information can also be obtained by running the program _m_._e_x_a_m_i_n_e_._t_a_p_e.
       _m_._e_x_a_m_i_n_e_._t_a_p_e will read any tape and provide the user with the	number
       of  files  on  a  tape, the number of records on a tape, and the record
       lengths.  Any subset of the image on the tape may be extracted.	For  a
       discussion of row and column extraction see the subheading enTITLEd ROW
       AND COLUMN EXTRACTION below.


       The next menu is:
	 Please mark an x by the bands you want extracted

			     _____ 1
			     _____ 2
			     _____ 3

       AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
		     (OR <Ctrl-C> TO CANCEL)
	SPOT imagery has three bands, but the user may want to extract a  sub-
       set  of these bands.  See the subheading in this entry enTITLEd ROW AND
       COLUMN EXTRACTION.


       The user then is asked to enter the prefix/group name  for  the	raster
       band  files  to	be  created.   This  name  will precede each band file
       extracted into GRASS.  For example, if two bands are extracted the fol-
       lowing two band files will result:


       _p_r_e_f_i_x_n_a_m_e_._1
       _p_r_e_f_i_x_n_a_m_e_._2


       The  specified  _p_r_e_f_i_x_n_a_m_e  will also automatically become the name for
       the imagery group file being created.  Each image or subset (i.e., each
       run of _i_._t_a_p_e_._s_p_o_t) should be given a unique prefix/group name.


	 The extraction process will begin by first skipping a number of files
       which are not data or  not  requested,  advancing  to  the  first  band
       requested,  forwarding  to  the	requested column, and then reading the
       data.  After extracting the requested rows and columns from each  band,
       the  program  creates support files for the raster band map layer.  The
       percent completion of  the  extraction  is  displayed  on  the  screen.
       Because	sometimes SPOT imagery is very large and is stored in multiple
       tape sets, the program is designed to read image by  pausing  when  the
       tape  need  to  be  changed  and inform the user to mount and load next
       tape.  The number of tapes required to store one scene depends  on  the
       number of bytes per inch (bpi) in which the data are stored.


       The  extracted band files will be listed as raster map layers available
       in the current MAPSET and may be displayed  using  the  GRASS  commands
       _d_._d_i_s_p_l_a_y, _d_._r_a_s_t, or _i_._p_o_i_n_t_s.

RROOWW AANNDD CCOOLLUUMMNN EEXXTTRRAACCTTIIOONN
       The  display options in GRASS allow the user to locate rows and columns
       on the digital image.  If enough disk space is available, one  band  of
       an  entire  image or one band of a portion of an image known to contain
       the area of interest, can be extracted and displayed.  The _m_e_a_s_u_r_e_m_e_n_t_s
       option  in  _d_._d_i_s_p_l_a_y, or _d_._w_h_e_r_e (following use of _d_._r_a_s_t) will echo x
       and y coordinates to the screen.  (These coordinates will display nega-
       tive  numbers  in  the north-south direction, but ignoring the negative
       sign will yield the row number.)  See the _i_m_a_g_e_r_y manual entry for fur-
       ther explanation.


       Each  scene  of a SPOT image contains filler on both the left and right
       sides of the quad.  The user may want to identify the  row  and	column
       numbers	in order to exclude the filler.  This filler will otherwise be
       extracted with the image and take up unnecessary disk space.


       If a photograph of the digital image is available, the rows and columns
       to  be  extracted  can be determined from it by associating inches with
       the total number of known rows and columns in the scene.  For  example,
       if the total length of the photograph is 12 inches, the total number of
       rows on the tape is 2000, and the  northwest  corner  of  the  area  of
       interest  begins  2  inches from the top of the photo, then: 12" / 2000
       rows = 2" / x rows x = 333.333

       The northwest corner of the area of interest starts at  row  333.   The
       starting  row,  ending  row,  starting column, and ending column can be
       calculated in this manner.

NNOOTTEESS
       After extracting an image from tape the geographic region definition in
       the  x,y  coordinate LOCATION_NAME will be set based upon the extracted
       rows and columns from the tape.	The  relationship  between  the  image
       rows  and  columns and the coordinates of the geographic region is dis-
       cussed in the _i_m_a_g_e_r_y format manual entry.


       This program is interactive and requires no command line arguments.

SSEEEE AALLSSOO
       _G_R_A_S_S _T_u_t_o_r_i_a_l_: _I_m_a_g_e _P_r_o _c_e_s_s_i_n_g


       _d_._d_i_s_p_l_a_y

       _d_._r_a_s_t

       _d_._w_h_e_r_e

       _i_._g_r_o_u_p

       _i_._p_o_i_n_t_s

       _i_._t_a_p_e_._m_s_s

       _i_._t_a_p_e_._m_s_s_._h

       _i_._t_a_p_e_._o_t_h_e_r

       _i_._t_a_p_e_._t_m

       _i_m_a_g_e_r_y

       _m_._e_x_a_m_i_n_e_._t_a_p_e

AAUUTTHHOORR
       Tao Wen, University of Illinois at Urbana-Champaign

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_1_/_2_5 _0_5_:_4_5_:_3_3 _$



GRASS 5.0							i.tape.spot(1)
