1 + | <casaxml xsi:schemaLocation="http://casa.nrao.edu/schema/casa.xsd file:///opt/casa/code/xmlcasa/xml/casa.xsd" xmlns="http://casa.nrao.edu/schema/psetTypes.html" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> |
2 + | |
3 + | <task type="function" name="msuvbin" category="manipulation, imaging" visibility="experimental"> |
4 + | <shortdescription>grid the visibility data onto a defined uniform grid (in the form of an ms); multiple MS\'s can be done onto the same grid</shortdescription> |
5 + | <description> |
6 + | msuvbin is a uv gridding task. The use is for large volumes |
7 + | of data (from multiple epochs) that needs to be imaged into |
8 + | one image. One way of proceeding is to image the epochs and |
9 + | average them after wards. Rather than doing this averaging |
10 + | the visibilities on a common uv grid has several convenience |
11 + | advantages like easily doing the proper weighted averaging and imaging. |
12 + | If an output grid already exists and a second ms is gridded on the grid |
13 + | then the output grid parameters is ignored but the existant grid is used. |
14 + | |
15 + | </description> |
16 + | <input> |
17 + | <param type="string" name="vis" mustexist="true"> |
18 + | <shortdescription>Name of input visibility </shortdescription> |
19 + | <description>Name of input visibility file (MS) |
20 + | default: none; |
21 + | </description> |
22 + | <value></value> |
23 + | </param> |
24 + | |
25 + | <param type="string" name="field"> |
26 + | <shortdescription>field(s) to select</shortdescription> |
27 + | <description>Field selection of input ms; use mssel syntax</description> |
28 + | <value></value> |
29 + | </param> |
30 + | |
31 + | <param type="string" name="spw"> |
32 + | <shortdescription>Spw selection</shortdescription> |
33 + | <description>Spw selection; mssel syntax </description> |
34 + | <value></value> |
35 + | </param> |
36 + | |
37 + | <param type="string" name="taql"> |
38 + | <shortdescription>TaQl string for data selection</shortdescription> |
39 + | <description>TaQl string for data selection; the advance user can do |
40 + | sophisticated data selection; see http://casacore.github.io/casacore-notes/199.html |
41 + | </description> |
42 + | <value></value> |
43 + | </param> |
44 + | |
45 + | <param type="string" name="outputvis"> |
46 + | <shortdescription>name of output uvgrid</shortdescription> |
47 + | <description>name of output uvgrid; if it existant the data will be binned additively into |
48 + | that uvgrid (as long as the parameters match for the grid description). If the gridded ms |
49 + | exists |
50 + | and the gridding parameters do not match the ones with which the grid was made--- |
51 + | msuvbin will exit with an exception |
52 + | </description> |
53 + | <value></value> |
54 + | </param> |
55 + | <param type="string" name="phasecenter"> |
56 + | <shortdescription>phase center of uv grid</shortdescription> |
57 + | <description>phase center of uv grid; if empty it will default |
58 + | the first field selected in the input ms |
59 + | </description> |
60 + | <value></value> |
61 + | </param> |
62 + | |
63 + | <param type="any" name="imsize"> |
64 + | <shortdescription>Number of pixels</shortdescription> |
65 + | <description>Number of pixels |
66 + | example: |
67 + | |
68 + | imsize = [350,250] |
69 + | imsize = 500 is equivalent to [500,500] |
70 + | |
71 + | To take proper advantage of internal optimized FFT routines, the |
72 + | number of pixels must be even and factorizable by 2,3,5 only. |
73 + | To find the nearest optimal imsize to that desired by the user, please use the following tool method: |
74 + | |
75 + | from casatools import synthesisutils |
76 + | su = synthesisutils() |
77 + | su.getOptimumSize(345) |
78 + | Output : 360 |
79 + | </description> |
80 + | <type>int</type><type>intVec</type> |
81 + | <value type="intVec"><value>100</value></value> |
82 + | </param> |
83 + | |
84 + | <param type="string" name="cell"> |
85 + | <shortdescription>pixel cell size defined in sky dimension</shortdescription> |
86 + | <description>pixel cell size defined in sky dimension |
87 + | This should be in the units of sky angle. Usually you want to have a pixel size that |
88 + | is smaller than the maximum resolution that can be expected from the data. |
89 + | |
90 + | </description> |
91 + | <value>1arcsec</value> |
92 + | </param> |
93 + | |
94 + | <param type="int" name="ncorr"> |
95 + | <shortdescription>number of correlations to store in grid</shortdescription> |
96 + | <description>number of correlations to store in grid |
97 + | if 1 is chosen and data have cross hands, then both XX and YY (or RR and LL) |
98 + | will be gridded on the same correlation plane (XX or RR as MS V2.0 does not support |
99 + | I as a correlation type). |
100 + | if 2 is chosen the parallel hands will be stored on independent grids for each frequency channel |
101 + | if 4 is chosen the all correlation type will be gridded independently. |
102 + | </description> |
103 + | <value>1</value> |
104 + | <allowed kind="enum"> |
105 + | <value>1</value> |
106 + | <value>2</value> |
107 + | <value>4</value> |
108 + | </allowed> |
109 + | </param> |
110 + | |
111 + | <param type="int" name="nchan"> |
112 + | <shortdescription>Number of spectral channels in grid</shortdescription> |
113 + | <description> |
114 + | Nunmber of spectral channels in the output grid |
115 + | </description> |
116 + | <value>1</value> |
117 + | </param> |
118 + | <param type="string" name="start"> |
119 + | <shortdescription>Frequency of first spectral channel</shortdescription> |
120 + | <description> |
121 + | Frequency of first channel of grid. If left empty, it will try to use the |
122 + | lowest frequency in the selected data |
123 + | </description> |
124 + | <value></value> |
125 + | </param> |
126 + | <param type="string" name="width"> |
127 + | <shortdescription>spectral channel width</shortdescription> |
128 + | <description> |
129 + | Spectral channel width. If left empty the badwidth of the selected data will be divided by the nchan |
130 + | selected to determine the width of an output channel. This happens only when not output grid already exists. |
131 + | </description> |
132 + | <value></value> |
133 + | </param> |
134 + | <param type="bool" name="wproject"> |
135 + | <shortdescription>Do wprojection correction while gridding</shortdescription> |
136 + | <description> |
137 + | Do wprojection correction while gridding. This should be used with care as it is known to have issues like perfomance |
138 + | and for Cotton-Schwab style cleaning. |
139 + | </description> |
140 + | <value>False</value> |
141 + | <allowed> |
142 + | <value>False</value> |
143 + | </allowed> |
144 + | </param> |
145 + | <param type="double" name="memfrac"> |
146 + | <shortdescription>Limit how much of memory to use</shortdescription> |
147 + | <description> |
148 + | Limit fraction of RAM available to use. Default is half. |
149 + | </description> |
150 + | <value>0.5</value> |
151 + | <allowed kind="range"> |
152 + | <value range="min">0.01</value> |
153 + | <value range="max">0.99</value> |
154 + | </allowed> |
155 + | </param> |
156 + | <param type="string" name="mode"> |
157 + | <shortdescription>when mode= "write_flags_back"Operation mode (bin/write_back_flags)</shortdescription> |
158 + | <description>when mode will transfer back flag from grid to input ms |
159 + | For this to work both the original ms and the gridded ms has to exist and the flags will be |
160 + | transferred from the gridded ms back to original ms. This is provided as a utility to |
161 + | msuvbinflagger task. |
162 + | </description> |
163 + | <value type="string">bin</value> |
164 + | <allowed kind="enum"> |
165 + | <value>bin</value> |
166 + | <value>write_flags_back</value> |
167 + | </allowed> |
168 + | </param> |
169 + | <param type="bool" name="flagbackup" subparam="true"> |
170 + | <shortdescription>backup flags before saving flags when using write_flags_back</shortdescription> |
171 + | <description>Backup flags before saving flags when using write_flags_back |
172 + | </description> |
173 + | <value type="bool">False</value> |
174 + | </param> |
175 + | |
176 + | <constraints> |
177 + | <when param="mode"> |
178 + | <equals type="string" value="write_flags_back"> |
179 + | <default param="flagbackup"><value>False</value></default> |
180 + | </equals> |
181 + | </when> |
182 + | </constraints> |
183 + | |
184 + | </input> |
185 + | <returns type="void"/> |
186 + | |
187 + | |
188 + | <example> |
189 + | |
190 + | |
191 + | |
192 + | |
193 + | Keyword arguments: |
194 + | vis -- Name of input visibility file |
195 + | default: none; example: vis='ngc5921.ms' |
196 + | field -- Field name list |
197 + | default: '' ==> all |
198 + | field = '1328+307' specifies source '1328+307' |
199 + | field = '4' specified field with index 4 |
200 + | spw -- Spw selection |
201 + | default: spw = '' (all spw) |
202 + | spw='2' |
203 + | taql --TaQl expression for data selection (see https://casacore.github.io/casacore-notes/199.html) |
204 + | default taql='' |
205 + | Example select all data where U > 1 m in the ms |
206 + | taql='UVW[0] > 1' |
207 + | outputvis -- name of output grid |
208 + | default: '' The user has to give something here |
209 + | phasecenter -- phasecenter of the grid |
210 + | default= '' |
211 + | phasecenter='J2000 18h03m04 -20d00m45.1' |
212 + | imsize -- number of pixels along the x and y axes of the grid |
213 + | default=100 |
214 + | imsize=[1000, 1000] |
215 + | cell -- cellsize of the grid (given in sky units) |
216 + | default: '1arcsec' |
217 + | cell='0.1arcsec' |
218 + | ncorr -- number of correlation/polarization plane in uv grid (allowed 1, 2, 4) |
219 + | default: 1 |
220 + | ncorr=4 |
221 + | nchan -- number of spectral channel |
222 + | default: 1 |
223 + | nchan=2000 |
224 + | start -- frequency of the first channel |
225 + | default: ''; User has to give something useful here |
226 + | width -- spectral channel width |
227 + | default: '' |
228 + | wproject -- do wprojection correction while gridding |
229 + | default: False |
230 + | wproject=True |
231 + | memfrac -- control how much of computer's memory is available for gridding |
232 + | default=0.5 |
233 + | memfrac=0.9 |
234 + | |
235 + | </example> |
236 + | </task> |
237 + | </casaxml> |