SCUBA sections

Since all the tasks rely on information in the NDF extensions that must correspond to data in the main DATA_ARRAY none of the SURF tasks can accept NDF sections [3]. On many occassions it is desirable to work on a subset of the observation (e.g. data from a specific exposure, integration or measurement) and the SURF package supports this via the concept of a `SCUBA section.'

A SCUBA section is indicated by using curly brackets after the file name (c.f. round brackets for NDF sections). The brackets then contain a specification that selects a certain part of the input data using the format shown in table .

Table: Special characters used to describe SCUBA sections

Specifier	Definition
{	Begins a SCUBA section
}	Ends a SCUBA section
b	indicates that the following numbers
	describe bolometer numbers (ie X axis)
p	indicates data position (ie Y axis).
	Can not be used in conjunction with s, e, i or m
s	switches
e	exposures
i	integrations
m	measurements
;	Separates components
,	Separates numbers
:	indicates a range of values
$-$	negates the section when placed after the last curly bracket

Note that SCUBA data is organised with bolometer number along the X axis and time (eg jiggle) along the Y axis so that the `b' specifier simply selects out bolometer data but the p, s, e, i and m specifiers select data by time.

Here are some example SCUBA sections:

test{}
select all points (good for resetting change_quality mask)

test{i3}
means select all bolometers in integration 3 for all measurements

test{b3:5}
select bolometers 3 to 5 for all points

test{e3}-
select everything except the 3rd exposure in each integration

test{e3;i4}
select the third exposure in integration 4

test{b5;p500:600}
select points 500 to 600 for bolometer 5

test{b5:7,19}
select bolometers 5 through 7 and bolometer 19

test{i1:4,7}{b3}
select integrations 1,2,3,4 and 7 and all data for bolometer 3.

test{b2}{i3}
select bolometer 2 and integration 3. Note that this is different to {b2;i3} which would only select the second bolometer from integration 3.

test{p50:100}{b32}-
select samples 1 through 49 and 101 through to the end, and all bolometers except number 32.

The tasks rebin, bolrebin, intrebin, change_data, change_quality and extract_data understand the concept of SCUBA sections.