mapcut

Description

mapcut modifies a map in various ways. It can single out an area (either circular or "rectangular") and set the temperature values to zero in the area or outside the area. Furthermore, it can systematically remove (by setting temperature value zero) or withhold multiple circular and/or "rectangular" areas by reading in a file containing those areas' radii/positions.

mapcut can dissect a "rectangular" area from a map and output to a file in FITS format, which can be viewed by xv program.

mapcut can truncate a map to a given temperature range. It can also display the temperature value at a given position in Galactic coordinate or read in multiple positions in various coordinate systems and display their temperature values.

Examples

1. Selecting one zone:
   • mapcut map.fits -rm -0.1,0,0.1,6.29 -o cutgalp.fits
     reads the map ' map.fits' and removes the Galactic plane area at $b=[-0.1,0.1]$ (radians) and output to ' cutgalp.fits'.

   • mapcut map.fits -keep 20.d,300.d,40.d,320.d -d 2.725 -o cutmap.fits
     reads the map ' map.fits' and keeps the rectangular area bounded by Galactic latitudes 20, 40 (degs) and longitudes 300, 320 (degs). The rest of pixels are set at T = 2.725 K and output to ' cutmap.fits'.

   • mapcut map.fits -keep -20.d,340.d,20.d,380.d -o cutmap.fits
     reads the map ' map.fits' and keeps the square area bounded by Galactic latitudes -20, 20 (degs) and longitudes 340, 20 (degs). The output is to ' cutmap.fits'.

   • mapcut map.fits -sq 20d,10d,50d,30d -o cut.fits
     dissects from ' map.fits' a rectangular map bounded by Galactic latitude 20 and 50 (degs) and longitude 10 and 30 (degs) and outputs this rectangular area to file ' cut.fits'.

2. Selecting multiple zones:
   • mapcut map.fits -zf zf.file -R -o map.out.fits
     reads map from file ' map.fits' and the Galactic coordinates of multiple zones from ASCII file ' zf.file' and set pixel values inside of these zones equal to zero. The output is in ' map.out.fits'.

3. Displaying temperature values:
   • mapcut map.q.fits -cr -14d,359d
     displays the temperature value at Galactic coordinates $(b,l)= (-14,359)$ (degs).

   • mapcut map.ilc.fits -sf pol.coord.file
     displays the temperature values of multiple positions (in spherical polar coordinates) on the map ' map.ilc.fits'. The positions are read in from file ' pol.coord.file', which includes 2 columns: $\theta$ and $\phi$.

   • mapcut map.fits -sfg gal.coord.file
     displays the temperature values of multiple positions (in Galactic coordinates) on the map ' map.fits'. The positions are read in from file ' gal.coord.file' , which includes 2 columns: $b$ and $l$.

4. Truncating the map temperature fluctuations:
   • mapcut -C -0.3,0.3 map.fits -o map.out.fits
     reads map from file ' map.fits' and truncates the temperature values to the range [-0.3,0.3] and outputs the map to ' map.out.fits'.