Update README.md

pynxtools/dataconverter/readers/xps/README.md

@@ -1,24 +1,42 @@
-# xps reader
+# XPS reader
 
-## Contact person in FAIRmat for this reader
-
-Rubel Mozumder
+## Purpose
+Translate diverse file formats from the scientific community and technology partners
+within the field of X-ray photoelectron spectroscopy into a standardized representation using the
+[NeXus](https://www.nexusformat.org/) application definition [NXmpes](https://fairmat-nfdi.github.io/nexus_definitions/classes/contributed_definitions/NXmpes.html#nxmpes).
 
-## Some Notes
+## Supported file formats
+The reader decides which parser to use based on the file extension of the files provided. For the main XPS files, the following file extensions are supported:
+- .sle: [SpecsLabProdigy](https://www.specs-group.com/nc/specs/products/detail/prodigy/) files, propietary format of SPECS GmbH (v1.6)
+- .xml: SpecsLab 2files, XML format from SPECS GmbH (v1.6)
+- .vms: VAMAS files, ISO standard data transfer format ([ISO 14976](https://www.iso.org/standard/24269.html)), both in regular and irregular format
+- .xy: SpecsLabProdigy export format in XY format (including all export settings)
+- .txt:
+  - exported by [Scienta Omicron](https://scientaomicron.com/en) instruments
+  - exported by [CasaXPS](https://www.casaxps.com/) analysis software
 
-1. The reader only compatible with xps data file (xml) of version 1.6.
-2. The reader builds on [NXmpes](https://fairmat-experimental.github.io/nexus-fairmat-proposal/1c3806dba40111f36a16d0205cc39a5b7d52ca2e/classes/contributed_definitions/NXmpes.html#nxmpes) definition language.
-3. The development process is intended in two steps.
-   i. [reader_utils](https://github.com/FAIRmat-NFDI/pynxtools/blob/master/pynxtools/dataconverter/readers/xps/reader_utils.py) parse the xps data from raw input files.
-   ii. Later the NXmpes nxdl template will be filled the parsed data comming from **reader_utils.py**.
-4. XPS data file (1.6v) does not have data/values for all requied fields and attributes. So, to launch **xps** reader user must provide a [xps eln](https://github.com/FAIRmat-NFDI/pynxtools/blob/master/tests/data/dataconverter/readers/xps/xps_eln.yaml) with [raw data](https://github.com/FAIRmat-NFDI/pynxtools/blob/master/tests/data/dataconverter/readers/xps/In-situ_PBTTT_XPS_SPECS.xml) file.
-5. Example script to run xps reader use code snipet below-
+We are continously working on adding parsers for other data formats and technology partners. If you would like to implement a parser for your data, feel free to get in contact.
 
+## Getting started
+An example script to run the XPS reader:
 ```sh
  ! dataconverter \
 --reader xps \
 --nxdl NXmpes \
---input-file $<xps-file location> \
---input-file $<eln-file location> \
---output <output-file location>.test.nxs
+--input-file $<xps-file path> \
+--input-file $<eln-file path> \
+--output <output-file path>.test.nxs
 ```
+Note that none of the supported file format have data/values for all required and recommended fields and attributes in NXmpes. In order for the validation step of the **XPS** reader to pass,
+you need to provide an ELN file that contains the missing values. An example can be found in  [*pynxtools/examples/xps*]().
+
+## Development Notes
+The development process is modular so that new parsers can be added. The read logic is the following.
+1. First, [*XpsDataFileParser*]([https://github.com/FAIRmat-NFDI/pynxtools/blob/master/pynxtools/dataconverter/readers/xps/file_parser.py#L39]) selects the proper parser based on the file extensions
+of the provided files. It then calls a sub-parser that can read files with such extensions and calls the *parse_file* function of that reader. In addition, it selects a proper config file from
+the *config* subfolder.
+2. Afterwards, the NXmpes nxdl template is filled with the data in *XpsDataFileParser* using the *config* file. Data that is not in the given main files can be added through the ELN file (and must
+be added for required fields in NXmpes).
+
+## Contact person in FAIRmat for this reader
+Lukas Pielsticker