Filling In the Spectrum Reading Form

1. Introduction

Words and phrases in capital letters are defined in the help which can be obtained by selecting "Words" from the help menu of the main window menubar.

The Read dialogue appears when the "Read" item is selected from the commands menu on the main window menubar or if "read" is typed in the text area to the right of "Type a command here ->".

The purpose of this dialogue is to read a SPECTRUM ( a set of x and y values ) from a file. The basic principle of this ( and all other dialogues ) is that you provide values for all the required items and then use a button to carry out the operation.

2. Items in the Read Dialogue

The read dialogue consists of a set of items for which you must provide values and a row of buttons which allow you to perform operations.

The items in the dialogue for which you must provide values are ( from top to bottom ):

• a) a TEXT AREA in which you must type the name of a file
• b) a TEXT AREA in which you must type the name of a directory
• c) a RADIO BOX which allows you to select a file type

The purposes of items d), e) and f) vary according to the setting of item c) ( i.e. the type of file specified ).

For file types SRS and XYZ

• d) a TEXT AREA in which you must specify the column of the file from which to read the x values of the spectrum
• e) a TEXT AREA in which you must specify the column of the file from which to read the y values of the spectrum
• f) a TEXT AREA which specifies how many lines in the file are data for the same point. This allows the use of SRS or XYZ file types which have several lines per point and also allows you to skip lines in your file. See below for more details.

For file type MCA:

d) and e) are not used.

f) specifies which spectrum to read if the file contains more than one.

For file type EXB:

d) and e) are as for SRS and XYZ

f) is not used

For file type OTOKO:

d) and e) are not used

f) specifies the starting point for reading each spectrum

For file types PDS DIF PLT and HKL:

d) e) and f) are not used.

For all file types:

• g) a TEXT AREA in which you may type a name for the spectrum

3. How to Specify Values for Each Type of Item

• a) TEXT AREAS: Move the mouse until the POINTER is in the darker recessed area. Click the left mouse button Type the required text. Text areas understand a small range of Emacs commands as well as delete and backspace. They also allow some shortcut operations with the mouse. For example a double click of the left mouse button SELECTS all the text. Delete will delete all selected text. Note that some text areas will only allow you to type an integer or floating point number.
• b) RADIO BOXES: Move the POINTER over one of the buttons in the RADIO BOX. Click the left mouse button. The button under the pointer will appear depressed. The others will be raised.
• c) PUSH BUTTONS: the buttons at the bottom of the Spectrum Reading Dialog are PUSH BUTTONS. These are operated by clicking the left mouse button while the pointer is over them.

4. What Each Item Requires from You

• a) the filename text area requires a filename. The file is used in read only mode. It must have read permission set for you.
• b) the directory text area requires a directory name. This is set to the name of the current directory when the dialogue is first created. The directory and filename together must specify a complete Unix pathname.
• c) the file type radio box specifies the type of file to read. At present the options are:

• SRS -- standard srs data file
• XYZ -- any data in columns
• MCA -- srs data file containing output from an mca
• EXB -- output from the SRS program EXBACK.
• OTOKO -- otoko files as produced by various srs stations
• PDS -- generated from podsum program, srs data and beam intensity factor.
• DIF -- generated by PKFit program, raw srs data, normalised data, difference data and HKL values.
• PLT --
• HKL -- HKL reciprical space values.

For SRS and XYZ data:

Note that the current version of Motplot discards most of the information in an SRS header file. This may not be the case in a future release.

d) and e) require the numbers of the columns in the file from which to read x and y values of the spectrum.

f) Motplot assumes that a line in a file ends with a carriage return. If each data point in the file actually consists of more than one line of data then this text area should be set to the relevant value. For example, these two data points taken from an SRS data file:

17002.40 959. 286450. 337. 33059. 1.

403. 447. 461. 485.

485. 535. 509. 484.

436. 497. 431. 473.

530. 0. 0. 0.

2039. 2443. 2498. 2411.

2474. 2481. 2402. 2794.

2709. 2938. 2614. 2593.

2663. 73411. 59259. 53091.

17006.70 959. 286789. 338. 32601. 1.

389. 428. 461. 404.

502. 573. 401. 465.

396. 486. 450. 501.

493. 0. 0. 0.

1986. 2469. 2433. 2371.

2516. 2469. 2441. 2717.

2642. 3024. 2529. 2490.

2514. 73657. 59013. 53447.

Each point consists of 46 values spread over 5 lines and the relevant value for this text area is 5. When the file type is set to SRS Motplot will try to set this value for you. It bases its guess on the format of the data so the value is not foolproof.

You can also set this number if you want to ignore lines in a file.

For MCA data:

f) The only information you must supply is which spectrum to read. Motplot automatically detects whether there is more than one spectrum in the file. It can also tell the difference between files which use 'END OF MEMORY' to separate spectra and those which use 'SPECTRUM END'. In addition it can usually determine those files which have a channel number in the first column and ignore it.

For EXB data:

This is data produced by EXBACK. This data can also be read by the XYZ option because its header information is currently discarded.

d) and e) require the numbers of the columns in the file from which to read x and y values of the spectrum.

For OTOKO data:

f) The Otoko reading functions read ALL of the spectra which are in the given file set. You can ignore one or more points at the beginning of each spectrum by setting the value of text area f).

For all data types:

g) this text area specifies a name for the spectrum. The spectrum will appear in the spectrum list as:

n :: name

if the name field is empty the program will create a name for the spectrum based on the column numbers and filename

5. What the Buttons Do

Operate the buttons by clicking the left mouse button while the pointer is over the raised area containing the button name. The buttons have the following actions:

• Read : will attempt to read a spectrum as specified
• Cancel : makes the dialogue invisible again without trying any other action.
• Select : puts up a window which allows browsing through directories. The Select window has its own help information.
• ShowFile : puts up a window displaying the contents of the file currently specified by the directory and filename text areas
• ReadList : puts up a window which will allow you to specify a file which contains a list of files from which to read spectra. The ReadList window has its own help information.
• Help : puts up a window containing this help