---
name: "writems"
section: "1"
platform: "linux"
package: "casacore-tools"
version: "3.7.1-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/writems"
---

# writems(1)

Create one or more MeasurementSets

## NAME

writems - Create one or more MeasurementSets

## SYNOPSIS

**writems** **parm=***value* ...

## Parameters

- **nms**

  Number of MeasurementSets to create (0 means 1 MS without suffix; default, \>0 also creates MultiMS)

- **msname**

  Name of the output MeasurementSet (suffix \_p\<i\> is added if nms\>0)

- **ra**

  One or more J2000 Right Ascensions (as hh:mm:ss.sss); defines the fields

- **dec**

  One or more J2000 Declinations (as dd.mm.ss.sss); defines the fields

- **anttab**

  Name of the ANTENNA table giving the antenna parameters to use (zero/empty values if not given)

- **startfreq**

  Start frequency (Hz) per spw (1 value counts on for other spws; default: 1e9)

- **chanwidth**

  Channel frequency width (Hz) per spw (1 value applies to all spws; default: 1e6)

- **starttime**

  Start time (e.g., 23Mar2016/12:00:00)

- **timestep**

  Time interval (sec; default: 1)

- **ntime**

  Number of time steps (default: 1) **ntimefield** Number of time steps per field (0=all fields for all times; default)

- **nspw**

  Number of spectral windows (default: 1)

- **npol**

  Number of polarizations per spectral window; 1 value applies to all spws (default: 4)

- **nchan**

  Number of channels per spectral window; 1 value applies to all spws (default: 256)

- **nant**

  Number of antennae to use; it anttab is given maximum to use is its size (default: 0)

- **calcuvw**

  Calculate UVW coordinates? (default: false)

- **autocorr**

  Write autocorrelations? (default: true)

- **weightspectrum**

  Write WEIGHT\_SPECTRUM column? (default: false)

- **imagercolumns**

  Write imager columns (MODEL\_DATA, CORRECTED\_DATA)? (default: false)

- **rowwise**

  Write the data row wise (thus a put per row) (default: true)

- **nflagbits**

  int Write multiple flag bits (0, 8, 16 or 32) mapped to FLAG (default: 0)

- **flagcolumn**

  Name of the FlagBits column if nflagbits\>0 (default: "FLAG\_BITS")

- **tilesize**

  Size of data tiles (KBytes); default is 1024

- **tilesizefreq**

  Number of channels in data tiles; default is all channels

- **multifile**

  Use the MultiFile feature? (default: false)

- **multihdf5**

  Use the MultiHDF5 feature? (default: false)

- **mfsize**

  MultiFile/HDF5 block size (KBytes); default is tilesize

- **ashdf5**

  bool Write the data in HDF5 format (default: false)