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Next: General Notes on DCR Tool Usage Up: Using the DCR Tool Previous: Using the DCR Tool GUI

Using the DCR Tool from the Command Line

The heart of the DCR Tool is the getscan function. It is used to mine the Measurement Set and return the data for a given scan into a simple Glish record, which can then be used for analysis using the large suite of functions and tools available. The getscan function has only two parameters, the scan number and (optionally) a focus parameter. Focus values may take up to several seconds to extract from the data, so they are not returned by default. The syntax for simple use of getscan (without focus data) is as follows:

- scan1 := mydcr.getscan(1)

This creates a Glish record structured as follows:

double     scan1.time
record     scan1.GO_header
double     scan1.GO_header.TIME
double     scan1.GO_header.INTERVAL
string     scan1.GO_header.SCAN
string     scan1.GO_header.PROJID
string     scan1.GO_header.SOURCE
string     scan1.GO_header.SCANID
string     scan1.GO_header.FITSVER
string     scan1.GO_header.OBSERVER
string     scan1.GO_header.PROCNAME
string     scan1.GO_header.PROCTYPE
integer    scan1.GO_header.PROCSEQN
integer    scan1.GO_header.PROCSIZE
string     scan1.GO_header.RADECSYS
double     scan1.GO_header.RAJ2000
double     scan1.GO_header.DECJ2000
double     scan1.GO_header.EQUINOX
double     scan1.GO_header.CNTRFREQ
string     scan1.GO_header.SWTCHSIG
integer    scan1.scan
float      scan1.data
float      scan1.lpc_az1
float      scan1.lpc_az2
float      scan1.lpc_el
record     scan1.pmodel
string     scan1.pmodel.FITSVER
float      scan1.pmodel.DELTAUTC
float      scan1.pmodel.IERSPMX
float      scan1.pmodel.IERSPMY
float      scan1.pmodel.MNTOFFAZ
float      scan1.pmodel.MNTOFFEL
float      scan1.pmodel.LPC_AZ1
float      scan1.pmodel.LPC_AZ2
float      scan1.pmodel.LPC_EL
string     scan1.pmodel.PNTMODEL
float      scan1.pmodel.PNTAZD00
float      scan1.pmodel.PNTAZB01
float      scan1.pmodel.PNTAZD01
float      scan1.pmodel.PNTAZA11
float      scan1.pmodel.PNTAZB11
float      scan1.pmodel.PNTAZC21
float      scan1.pmodel.PNTAZD21
float      scan1.pmodel.PNTELD00
float      scan1.pmodel.PNTELC10
float      scan1.pmodel.PNTELD10
float      scan1.pmodel.PNTELB01
float      scan1.pmodel.PNTELD01
string     scan1.pmodel.DIABMODE
string     scan1.pmodel.POLARMTN
string     scan1.pmodel.COSVMODE
float      scan1.pmodel.AMBTEMP
float      scan1.pmodel.AMBPRESS
float      scan1.pmodel.AMBHUMID
string     scan1.pmodel.OPTICSMD
string     scan1.pmodel.FOCTRMOD
string     scan1.pmodel.FOCPATM
double     scan1.az
double     scan1.el
double     scan1.ra
double     scan1.dec

In fields where it is appropriate, the values are stored in arrays. For example, scan1.time is an array containing the time for each of the samples in the scan. The data are in scan1.data, which is a 3-D array with the first index pointing to receiver, the second to phase, and the third to the sample number. The third sample from receiver 0 and phase 1 would then be accesses as Glish value scan1.data[0,1,3].

The full syntax of the getscan function is:

scan1 := mydcr.getscan(scan,getFocus=F)

The getFocus parameter can be omitted to pass the default F value. If set to T, the relevant focus arrays will be included into the returned record. For prime focus observations, these are:

string     scan1.focusparam
string     scan1.optics
float      scan1.PF_FOCUS
float      scan1.PF_ROTATION
float      scan1.PF_X

and for gregorian focus observations, these are:

string     scan1.focusparam
string     scan1.optics
float      scan1.SR_XP
float      scan1.SR_YP
float      scan1.SR_ZP
float      scan1.SR_XT
float      scan1.SR_YT
float      scan1.SR_ZT

The focusparam field in the returned record is an indicator to which focus values are available in the given record. For the cases above, scan1.focusparam has the value 'all'. It is possible to load only one focus parameter into the returned record by sending the desired parameter in the getscan function. For example:

scan3 := md.getscan(3,'PF_FOCUS')

This getscan call produces scan3.focusparam equal to 'PF_FOCUS' and a single entry in the record for focus:

float      scan3.FOCUS

The following commands, then, show a way to plot the focus values separately from the canned focus procedures in the DCR tool:

- md := dcr('pnt_prime_12_DCR') 
- scan2030 := md.getscan(2030,'PF_FOCUS') 
- pg.ploty(scan2030.FOCUS)

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