Add/Update README and hero figure

README.md

@@ -1,55 +1,125 @@
 ---
-{}
+configs:
+- config_name: default
+  data_dir: mmu_vipers_w4/dataset
+tags:
+- astronomy
+license: cc-by-4.0
+pretty_name: mmu_vipers_w4
+size_categories:
+- 10K<n<100K
 ---
 
-    ---
-    description: 'The "VIMOS Public Extragalactic Redshift Survey" (VIPERS) mapped the
-  spatial distribution of over 90,000 galaxies at z~1, using the VIMOS spectrograph
-  at the Very Large Telescope, covering nearly 24 square degrees. It optimized multi-band
-  photometry and VIMOS''s multiplexing capability to focus on the 0.5 < z < 1.2 redshift
-  range, producing a data set comparable to local universe surveys like SDSS and 2dFGRS.
-  The HATS catalog was generated from https://huggingface.co/datasets/MultimodalUniverse/vipers
-
-  '
-homepage: http://www.vipers.inaf.it/
-version: 1.0.0
-citation: "% % ACKNOWLEDGEMENTS\n% % From: http://www.vipers.inaf.it/ \n% \n% We kindly\
-  \ request all papers using VIPERS data to add the following text to their acknowledgment\
-  \ section: \n% \n% This paper uses data from the VIMOS Public Extragalactic Redshift\
-  \ Survey (VIPERS). VIPERS has been performed using the ESO Very Large Telescope,\
-  \ under the \"Large Programme\" 182.A-0886. The participating institutions and funding\
-  \ agencies are listed at http://vipers.inaf.it\n% \n% CITATION\n@article{scodeggio2018vimos,\n\
-  \  title={The VIMOS Public Extragalactic Redshift Survey (VIPERS)-Full spectroscopic\
-  \ data and auxiliary information release (PDR-2)},\n  author={Scodeggio, MARCO and\
-  \ Guzzo, L and Garilli, BIANCA and Granett, BR and Bolzonella, M and De La Torre,\
-  \ S and Abbas, U and Adami, C and Arnouts, S and Bottini, D and others},\n  journal={Astronomy\
-  \ \\& Astrophysics},\n  volume={609},\n  pages={A84},\n  year={2018},\n  publisher={EDP\
-  \ Sciences}\n}\n"
-    ---
-
-    # Vipers Dataset
-
-    
-
-    The "VIMOS Public Extragalactic Redshift Survey" (VIPERS) mapped the spatial distribution of over 90,000 galaxies at z~1, using the VIMOS spectrograph at the Very Large Telescope, covering nearly 24 square degrees. It optimized multi-band photometry and VIMOS's multiplexing capability to focus on the 0.5 < z < 1.2 redshift range, producing a data set comparable to local universe surveys like SDSS and 2dFGRS.
-
-
-    % % ACKNOWLEDGEMENTS
-% % From: http://www.vipers.inaf.it/ 
-% 
-% We kindly request all papers using VIPERS data to add the following text to their acknowledgment section: 
-% 
-% This paper uses data from the VIMOS Public Extragalactic Redshift Survey (VIPERS). VIPERS has been performed using the ESO Very Large Telescope, under the "Large Programme" 182.A-0886. The participating institutions and funding agencies are listed at http://vipers.inaf.it
-% 
-% CITATION
-@article{scodeggio2018vimos,
-  title={The VIMOS Public Extragalactic Redshift Survey (VIPERS)-Full spectroscopic data and auxiliary information release (PDR-2)},
-  author={Scodeggio, MARCO and Guzzo, L and Garilli, BIANCA and Granett, BR and Bolzonella, M and De La Torre, S and Abbas, U and Adami, C and Arnouts, S and Bottini, D and others},
-  journal={Astronomy \& Astrophysics},
-  volume={609},
-  pages={A84},
-  year={2018},
-  publisher={EDP Sciences}
-}
-
-    
+<div align="center">
+<img src="example_figure.png" width="600">
+</div>
+
+# mmu_vipers_w4 HATS Catalog Collection
+
+This is the collection of HATS catalogs representing mmu_vipers_w4.
+
+This dataset is part of the [Multimodal Universe](https://github.com/MultimodalUniverse/MultimodalUniverse),
+a large-scale collection of multimodal astronomical data. For full details, see the paper:
+[The Multimodal Universe: Enabling Large-Scale Machine Learning with 100TBs of Astronomical Scientific Data](https://arxiv.org/abs/2412.02527).
+
+### Access the catalog
+
+We recommend the use of the [LSDB](https://lsdb.io) Python framework to access HATS catalogs.
+LSDB can be installed via `pip install lsdb` or `conda install conda-forge::lsdb`,
+see more details [in the docs](https://docs.lsdb.io/).
+The following code provides a minimal example of opening this catalog:
+
+```python
+import lsdb
+
+# Full sky coverage.
+catalog = lsdb.open_catalog("https://huggingface.co/datasets/LSDB/mmu_vipers_w4")
+# One-degree cone.
+catalog = lsdb.open_catalog(
+    "https://huggingface.co/datasets/LSDB/mmu_vipers_w4",
+    search_filter=lsdb.ConeSearch(ra=333.0, dec=1.0, radius_arcsec=3600.0),
+)
+```
+
+Each catalog in this collection is represented as a separate [Apache Parquet dataset](https://arrow.apache.org/docs/python/dataset.html) and can be accessed with a variety of tools, including `pandas`, `pyarrow`, `dask`, `Spark`, `DuckDB`.
+
+### File structure
+
+This catalog is represented by the following files and directories:
+
+- [`collection.properties`](https://huggingface.co/datasets/LSDB/mmu_vipers_w4/collection.properties) � textual metadata file describing the HATS collection of catalogs
+- [`mmu_vipers_w4`](https://huggingface.co/datasets/LSDB/mmu_vipers_w4/mmu_vipers_w4) � main HATS catalog directory
+  - [`dataset/`](https://huggingface.co/datasets/LSDB/mmu_vipers_w4/mmu_vipers_w4/dataset/) � Apache Parquet dataset directory for the main catalog
+    - ... parquet metadata and data files in sub directories ...
+  - [`hats.properties`](https://huggingface.co/datasets/LSDB/mmu_vipers_w4/mmu_vipers_w4/hats.properties) � textual metadata file describing the main HATS catalog
+  - [`partition_info.csv`](https://huggingface.co/datasets/LSDB/mmu_vipers_w4/mmu_vipers_w4/partition_info.csv) � CSV file with a list of catalog HEALPix tiles (catalog partitions)
+  - [`skymap.fits`](https://huggingface.co/datasets/LSDB/mmu_vipers_w4/mmu_vipers_w4/skymap.fits) � HEALPix skymap FITS file with row-counts per HEALPix tile of fixed order 10
+- [`mmu_vipers_w4_10arcs/`](https://huggingface.co/datasets/LSDB/mmu_vipers_w4/mmu_vipers_w4_10arcs) � default margin catalog to ensure data completeness in cross-matching, the margin threshold is 10.0 arcseconds
+  - ... margin catalog files and directories ...
+
+### Catalog metadata
+
+Metadata of the main HATS catalog, excluding margins and indexes:
+
+| **Number of rows** | **Number of columns** | **Number of partitions** | **Size on disk** | **HATS Builder** |
+| --- | --- | --- | --- | --- |
+| 30,979 | 9 | 9 | 321.4 MiB | hats-import v0.7.1, hats v0.7.1 |
+
+
+### Catalog columns
+
+The main HATS catalog contains the following columns:
+
+| **Name** |  **`_healpix_29`** | **`spectrum.flux`** | **`spectrum.ivar`** | **`spectrum.lambda`** | **`spectrum.mask`** | **`REDSHIFT`** | **`REDFLAG`** | **`EXPTIME`** | **`NORM`** | **`MAG`** | **`ra`** | **`dec`** | **`object_id`** |
+| --- |  --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
+| **Data Type** |  int64 | list[float] | list[float] | list[float] | list[float] | float | float | float | float | float | float | float | string |
+| **Nested?** |  � | spectrum | spectrum | spectrum | spectrum | � | � | � | � | � | � | � | � |
+| **Value count** |  30,979 | 17,255,303 | 17,255,303 | 17,255,303 | 17,255,303 | 30,979 | 30,979 | 30,979 | 30,979 | 30,979 | 30,979 | 30,979 | 30,979 |
+| **Example row** |  1339537029392400028 | [0.1504, 0.1525, 0.1538, 0.1543, � (557 total)] | [8.585e-17, 1.011e-16, 1.137e-16, � (557 total)] | [5514, 5521, 5529, 5536, 5543, � (557 total)] | [2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, � (557 total)] | 0.7298 | 0.7298 | 540 | 2.768 | 21.98 | 333.4 | 1.077 | 404055346.0 |
+| **Minimum value** |  1339504075142965993 | -1759.751953125 | -2.9612807435456968e-18 | 5514.27978515625 | -0.0 | -0.0 | -0.0 | 540.0 | 0.021366773173213005 | 15.182700157165527 | 330.0451965332031 | 0.8620766997337341 | 401007640.0 |
+| **Maximum value** |  1341678248016204204 | 2786.57177734375 | 7.853208785491006e-07 | 9484.1201171875 | 3.0 | 4.395299911499023 | 4.395299911499023 | 540.0 | 3519.447509765625 | 23.96969985961914 | 335.39093017578125 | 2.3695244789123535 | 411162926.0 |
+
+
+"Nested" indicates whether the column is stored as a nested field inside another "struct" column.
+
+
+"Value count" may be different from the total number of rows for nested columns: each nested element is counted as a single value.
+
+
+
+
+### Crossmatch with another catalog
+
+HATS catalogs can be efficiently crossmatched using [LSDB](https://lsdb.io),
+which leverages the HEALPix partitioning to avoid loading the full datasets into memory:
+
+```python
+import lsdb
+
+mmu_vipers_w4 = lsdb.open_catalog("https://huggingface.co/datasets/LSDB/mmu_vipers_w4")
+other = lsdb.open_catalog("https://huggingface.co/datasets/<org>/<other_catalog>")
+
+crossmatched = mmu_vipers_w4.crossmatch(other, radius_arcsec=1.0)
+print(crossmatched)
+```
+
+See the [LSDB documentation](https://docs.lsdb.io/) for more details on crossmatching and other operations.
+
+### Dataset-specific context
+
+**Original survey**  
+This dataset is based on the VIMOS Public Extragalactic Redshift Survey (VIPERS), which provides optical spectra of galaxies in the redshift range 0.5 < z < 1.0.
+
+**Data modality**  
+The dataset consists of fixed-size optical spectra (1 × 557) covering a wavelength range from 5514 Å to 9484 Å. Each spectrum includes flux values, the corresponding wavelength vector, inverse variance (ivar), and a mask indicating the quality of each measurement. The dataset contains approximately 90,000 galaxy spectra.
+
+**Typical use cases**  
+This dataset has been used in a number of scientific publications, as well as in
+machine learning specific applications, including source identification with SVMs and
+galaxy classification with unsupervised methods.
+
+**Caveats**  
+The dataset includes spectra that have been normalized and transformed during preprocessing to ensure consistency with other datasets.
+
+**Citation**  
+This dataset uses data from the VIMOS Public Extragalactic Redshift Survey (VIPERS), obtained with the ESO Very Large Telescope. Users should acknowledge the [VIPERS survey](http://vipers.inaf.it) and its participating institutions.