Spatial Analysis

New parameter files for spatial analysis tasks

Overview

Some of the features of the new parameter files:

• they are shorter and easier to use
• identification of detector and observation mode
• ROSAT survey defaults supported
• general source detection parameter file sopar.par not needed
• for expert use: get all the old parameters, if needed
• old-style parameter files for PSPC still work
• no need to change existing user-written procedures

Shorter and easier to use

The parameter files for the main source detection tasks

have been simplified. All parameters have been removed, which are either

• rarely used, i.e. changed by the user
• not necessary for standard applications
• are specific for a certain experiment/detector combination, but have firm default values

Also, some parameters are now read directly from the descriptors of the input images or tables. This makes it easier for the casual EXSAS user to perform source detection tasks. Also there should be no need anymore to look up certain instrument-specific parameter settings in the user's guide.

Identification of detector and observation mode

Every parameter file now contains two new parameters: an identifier for the experiment/detector combination and for the observing mode.

Example:

These additional parameters have two functions. First, they tell the user, whether the parameter file he has just created, and its defaults, are ok for his data. Second, some of the removed instrumental parameters (which are still needed within the main routine) are initiated properly by the parameter file reading subroutine. This sub first reads the two parameters MISSION,DETECTOR and OBS_MODE, and then initializes all the other parameters to the proper defaults. All subsequently read parameters overwrite the defaults.

ROSAT survey defaults supported

CREATE/PARFIL now supports also the option ROSAT,SURVEY, additional to ROSAT,PSPC, ROSAT,HRI, and ROSAT,WFC.

Example:

resulting in a parameterfile dlpar.par:

All parameters will be initialized to the default values for ROSAT survey data. From now on option 'ROSAT,PSPC' should be used only for pointing data.

General source detection parameter file sopar.par not needed anymore

The general source detection parameter file sopar.par now contains only the file names of the parameter files of the subsequent source detection commands. It is no longer necessary to create this parameter file before running source detection tasks. However, it will be created automatically with default file names when running the first source detection command.

The user has to create and edit this file only, when others than the default parameter file names shall be used in source detection.

For expert use: get all the old parameters, if needed

In a few special cases there may be the need to access some of the parameters which have now been removed. If this happens, the parameter files have to be created with the new [extended] option of CREATE/PARFIL.

Example:

This will result in an extended parameter file containing also all the "removed" parameters, which can be modified as before. The default is 'noextend'.

The same happens, when (e.g. in an old user-defined procedure) a "removed" parameter is accessed via WRITE/PARFIL. The modified parameter file will then also be extended.

Old-style parameter files for PSPC still work

Old parameter files for PSPC will still work.

For HRI and WFC it is recommended that you recreate your parameter files with

Note for WFC users: Users working on WFC data taken through one of the WFC filters S1, S2, P1 or P2 should use the [extended] option in every case when using

Edit the parameter file and look for Parameter FWHM_CAL_FILE. If it is present it should be set to the proper name of the FWHM table (EXSAS_CAL:fwros1.tbl or fwros2, fwrop1, fwrop2 respectively). Alternatively, you could use CREATE/PARFIL without the extended option, and then command (example for filter S2):

Contact the undersigned in case of problems.

No need to change existing user-written procedures

Existing procedures involving the handling of parameter files, i.e. using CREATE/PARFIL or WRITE/PARFIL, dont have to be changed. However, some things can now be done in a simpler way. So probably you could could get rid of some lines of code.

In case of problems or comments:
send e-mail to xray-info @ mpe . mpg . de

© X-Ray Group at MPE (group)
last update:1998/12/07 12:40:02, editor of this page:Stefan Döbereiner