Geografic-Information-System/lib/gis/new_des

G_get_map_row()
  If the map is floating-point, quantize the floating-point values to integer
  using the quantization rules established for the map when the map was opened
  for reading. 

  NULL values are converted to zeros. 
  (This routine is deprecated)

G_put_map_row() 
   Zero values are converted to NULLs. Write a row of the NULL value bit map.
   (This routine is deprecated) 
               ------------------------------------------------------------
	       G_get_map_row()          G_get_raster_row()

	       MAP w/NULLs    NULL and 0 -> 0          NULL->NULL, 0->0
	       MAP w/o NULLs  NULL and 0 -> 0          NULL and 0 -> NULL
	       ------------------------------------------------------------
	       w/NULLS   means with NULL bit map
	       w/o NULLS means without NULL bit map


New routines:

G_get_f/d_raster_row (int fd, FCELL fcell, int row) 
   Read a row from the raster map open on fd into the float array fcell
 performing type conversions as necessary based on the actual storage type of
   the map. Masking, resampling into the current region. NULL-values are
   always embedded in fcell (never converted to a value). 

G_put_f_raster_row (int fd, FCELL *fcell) 
   Write the next row of the raster map open on fd from the float array fcell,
   performing type conversion to the actual storage type of the resultant map.
   Keep track of the range of floating-point values. Also writes the NULL-value
   bitmap from the NULL-values embedded in the fcell array. 


G_get_raster_row (int fd, CELL buf, int row) 
   Reads a row from NULL value bitmap file for the raster map open for read on
   fd. If there is no bitmap file, then this routine simulates the read 
   as follows:
      non-zero values in the raster map correspond to non-NULL; zero values
      correspond to NULL. 
   (as opposed to the deprecated function G_get_map_row() which converts NULL 
   values to zero.)

G_put_raster_row (int fd, CELL buf) 
   Writes a row of raster data and a row of the null-value bitmap, only treating
   NULL as NULL. (As opposed to the deprecated function 
   G_put_map_row() which treats zero values also as NULL.) 

G_insert_[d/f_]null_values (cell, flags, count) 

   CELL *cell; 
   char *flags; 
   int count; 

   For each of the count flags which is true(!=0), set the corresponding cell 
   to the NULL value. 

Held 13 messages in /usr/spool/mail/olga
amber olga> mail shapiro
Subject: G_put_map_row() updating range file.
The way put_row is implemented right now, the updating of range happens
after writing the row by calling G_update_range(range,row,ncols)

Since you want all 0's to go to NULL, it is really hard to implement,
because I can't modify the row buffer. So I have 2 options:
1. make a new update_range() low level function which takes
ignore_zeros flag as argument.

2. to call update with each cell idividually and check for 0's
what should I do?


pen_cell_new_random() should cause the NULL-value bit map to NOT be created.

Yes, give an error - unless you think you can implement random writing of the NULL bit map.
|
|so I should give an error when G_put_map_row_random() is called
|for floating or double maps?
|Right now I convert it to float or double and do the random writes
|which I implemented for float and double.
|Olga
|