# SpectralIndices.jl

<p align="center">
    <img width="400px" src="docs/src/assets/logo.png"/>
</p>

| **Documentation** | **Build Status** | **Julia** | **Testing** |
|:-----------------:|:----------------:|:---------:|:-----------:|
| [![docs][docs-img]][docs-url] | [![CI][ci-img]][ci-url] | [![Julia][julia-img]][julia-url] [![Code Style: Blue][style-img]][style-url] | [![Aqua QA][aqua-img]][aqua-url] [![JET][jet-img]][jet-url] [![codecov][cc-img]][cc-url] |

[docs-img]: https://img.shields.io/badge/docs-stable-blue.svg
[docs-url]: https://awesome-spectral-indices.github.io/SpectralIndices.jl/dev/

[ci-img]: https://github.com/awesome-spectral-indices/SpectralIndices.jl/actions/workflows/CI.yml/badge.svg
[ci-url]: https://github.com/awesome-spectral-indices/SpectralIndices.jl/actions/workflows/CI.yml

[cc-img]: https://codecov.io/gh/awesome-spectral-indices/SpectralIndices.jl/graph/badge.svg?token=0IRRDAZM0U
[cc-url]: https://codecov.io/gh/awesome-spectral-indices/SpectralIndices.jl

[julia-img]: https://img.shields.io/badge/julia-v1.10+-blue.svg
[julia-url]: https://julialang.org/

[style-img]: https://img.shields.io/static/v1?label=code%20style&message=SciML&color=9558b2&labelColor=389826
[style-url]: https://github.com/SciML/SciMLStyle

[aqua-img]: https://raw.githubusercontent.com/JuliaTesting/Aqua.jl/master/badge.svg
[aqua-url]: https://github.com/JuliaTesting/Aqua.jl

[jet-img]: https://img.shields.io/badge/%E2%9C%88%EF%B8%8F%20tested%20with%20-%20JET.jl%20-%20red
[jet-url]: https://github.com/aviatesk/JET.jl

## Overview 📖

SpectralIndices.jl is a Julia package for working with spectral indices commonly used in remote sensing and earth observation applications. It provides a convenient way to compute various spectral indices using Julia's high-performance capabilities.

## Features 🚀

- Computation for a wide range of spectral indices 
- Computation support for `Float64`, `Float32` and `Float16` at index formula level to support fast computation for ML applications
- Support for various data types, including but not limited to (see this [issue](https://github.com/awesome-spectral-indices/SpectralIndices.jl/issues/8) for an updated list and WIP)
  - [x] Arrays
  - [x] DataFrames
  - [x] YAXArrays
- Flexible parameter input options
- Compatibility with multiple remote sensing platforms and sensors

## Installation 💻
SpectralIndices.jl is registered in the general registry, please install it using the following:
```julia_repl
julia> ]
pkg> add SpectralIndices
```
or
```julia
using Pkg
Pkg.add("SpectralIndices")
```

## Usage 🛠️

```julia
using SpectralIndices
using DataFrames

# Compute NDVI with direct parameter input
result = compute_index("NDVI", N = 0.643, R = 0.175)

# Compute NDVI with direct parameter input and direct NDVI call
result = compute_index(NDVI, N = 0.643, R = 0.175)

# Compute multiple indices with array inputs
multi_result = compute_index(["NDVI", "SAVI"], N = fill(0.643, 5), R = fill(0.175, 5), L = fill(0.5, 5))

# use Dataframes
df = DataFrame(N = [0.643, 0.560], R = [0.175, 0.225])
result_df_single = compute_index("NDVI", df)
# Multiple inputs in a dataframe
df = DataFrame(N = [0.643, 0.560], R = [0.175, 0.225], L = [0.5, 0.5])
result_df_multiple = compute_index(["NDVI", "SAVI"], df)
```

To compute at custom Float precision input the bands at the chosen precision and specify the Float type to the `compute_index` function
```julia
# Compute NDVI with direct parameter input
result = compute_index(Float32, "NDVI", N = Float32(0.643), R = Float32(0.175))
```

## Code Structure

![fig1](https://github.com/awesome-spectral-indices/SpectralIndices.jl/assets/10376688/fb680f5a-7130-49fc-ae20-386fed3777ed)

## Contributing 🤝

Contributions to SpectralIndices.jl are welcome! If you would like to contribute, please see our Contribution Guidelines for more information.

## License 📜

SpectralIndices.jl is licensed under the MIT License. See [LICENSE](https://github.com/awesome-spectral-indices/SpectralIndices.jl/blob/main/LICENSE) for more information.

## Acknowledgments ✨

This package is inspired by the [Spyndex](https://github.com/awesome-spectral-indices/spyndex) Python library for spectral indices. The logo is AI-generated by dalle3 through ChatGPT and modified by the talented [David Montero](https://github.com/davemlz).

## Support 🆘

If you have any questions, issues, or feature requests, please open an issue or contact us via email.

## Citation 🔗

If you use SpectralIndices.jl in your research, please consider citing it using the following DOI:

```bibtex
@article{martinuzzi2024spectral,
  title = {SpectralIndices.jl: Streamlining spectral indices access and computation for Earth system research},
  volume = {XLVIII-4/W12-2024},
  ISSN = {2194-9034},
  url = {http://dx.doi.org/10.5194/isprs-archives-XLVIII-4-W12-2024-89-2024},
  DOI = {10.5194/isprs-archives-xlviii-4-w12-2024-89-2024},
  journal = {The International Archives of the Photogrammetry,  Remote Sensing and Spatial Information Sciences},
  publisher = {Copernicus GmbH},
  author = {Martinuzzi,  Francesco and Mahecha,  Miguel D. and Montero,  David and Alonso,  Lazaro and Mora,  Karin},
  year = {2024},
  month = jun,
  pages = {89–95}
}
```
Also consider citing the paper introducing the Awesome Spectral Indices collection:

```bibtex
@article{montero2023standardized,
  title={A standardized catalogue of spectral indices to advance the use of remote sensing in Earth system research},
  author={Montero, David and Aybar, C{\'e}sar and Mahecha, Miguel D and Martinuzzi, Francesco and S{\"o}chting, Maximilian and Wieneke, Sebastian},
  journal={Scientific Data},
  volume={10},
  number={1},
  pages={197},
  year={2023},
  publisher={Nature Publishing Group UK London}
}
```
[![RSC4Earth](https://github.com/davemlz/sen2nbar/raw/main/docs/_static/esds.png)](https://rsc4earth.de/authors/esds/)