## Multi-Field UV_MAP processing

When UV_MAP encounters more than 1 field in a UV Table, it first verifies whether phase (code_uvt_loff & code_uvt_moff) or pointing (code_uvt_xoff & code_uvt_yoff) offsets are present. In case phase offsets are present, it first automatically process the UV table to recenter it onto a common phase center, and converts the offsets to pointing offsets. Here, the centroid of all fields is used by default as phase center. This action can be obtained independently by the UV_SHIFT command. When pointing offsets are present, this step is no longer required and imaging can proceed immediately. Further changes of field center and map orientation are dictated by variables MAP_SHIFT, MAP_RA, MAP_DEC, and MAP_ANGLE as for single fields.

Dirty and primary beams are frequency sliced in "chunks" as for single fields.

SHOW FIELDS (or VIEW FIELDS) can display the observed pointing centers.

The display of frequency dependent beams is still to be implemented for Mosaics, as SHOW or VIEW only handles 3-D data cubes.

With such data, UV_MAP automatically activates the MOSAIC mode for further image processing.