# NDVI-Based Land Use and Land Cover Samples for Porto Velho, Brazilian Amazon

Version 2 – standardized file naming and English-language CSV exports. The NDVI values are identical to version 1.

## Overview

- 90 sample points in the municipality of Porto Velho, Rondônia, Brazil
- 3 classes, 30 samples each: Agriculture, Forest, Pasture
- MODIS NDVI time series (MOD13Q1/Terra and MYD13Q1/Aqua, 250 m) exported from the SATVeg platform (Embrapa)
- Period: 2000-02-18 to 2025-02-02, 1,094 observations per sample (16-day spacing until June 2002, 8-day spacing afterwards with Terra and Aqua combined)
- Class labels were assigned by visual interpretation of satellite imagery for the reference year 2024. They do not represent annually validated labels for earlier years. Some series may include earlier land uses, such as forest converted to pasture.

## Structure

```
SATVeg-data_v2/
├── README.md
├── samples.csv            # one row per sample: id, class, coordinates, metadata
├── samples.geojson        # sample points (longitude/latitude)
├── ndvi_timeseries.csv    # all 90 time series in long format (98,460 rows)
├── Agriculture/
│   └── Agriculture_01/
│       ├── Agriculture_01_ndvi.csv     # time series, English headers, ISO dates
│       ├── Agriculture_01_satveg.xlsx  # original SATVeg export (unchanged)
│       └── Agriculture_01_profile.png  # original SATVeg plot (unchanged)
├── Forest/   (Forest_01 … Forest_30)
└── Pasture/  (Pasture_01 … Pasture_30)
```

## Columns

| Column | Description |
|---|---|
| `sample_id` | Sample identifier (`<Class>_<NN>`) |
| `class` | LULC class in the reference year 2024 |
| `longitude`, `latitude` | Geographic coordinates in decimal degrees, as exported by SATVeg |
| `date` | Image composite date (YYYY-MM-DD) |
| `ndvi` | Original NDVI value (SATVeg column "NDVI") |
| `ndvi_prefiltered` | NDVI after the SATVeg pre-filter (column "Pré-Filtro") |
| `ndvi_savgol` | NDVI smoothed with the Savitzky–Golay filter (column "Savitzky-Golay") |

`samples.csv` also includes `municipality`, `state`, `country`, `reference_year`, `n_observations`, `start_date`, `end_date`, and `original_folder` (the folder name in version 1).

## Original SATVeg spreadsheets

The `*_satveg.xlsx` files are the unchanged SATVeg exports, with Portuguese headers: "Ponto:" (longitude, latitude), "Município:", "Data" (DD/MM/YYYY), "NDVI", "Pré-Filtro", "Savitzky-Golay".