Functions Reference - PASCAL NDVI Block

Index

1. Main Functions
2. Preprocessing
3. Logging & Traceability
4. Configuration

Main Functions

calculate_ndvi(red_band: np.ndarray, nir_band: np.ndarray) -> np.ndarray

Calculates the Normalized Difference Vegetation Index (NDVI).

Parameters:

• red_band: NumPy array with red band reflectance values
• nir_band: NumPy array with near-infrared band reflectance values

Returns:

• NumPy array with NDVI values in range [-1, 1]

Validations:

• Bands must have same dimensions
• Values cannot be all zero
• Division by zero handling

calculate_savi(red_band: np.ndarray, nir_band: np.ndarray, l: float = 0.5) -> np.ndarray

Calculates the Soil Adjusted Vegetation Index (SAVI).

Parameters:

• red_band: NumPy array with red band reflectance values
• nir_band: NumPy array with near-infrared band reflectance values
• l: Soil adjustment factor (0.0 - 1.0)

Returns:

• NumPy array with SAVI values

Validations:

• L factor must be between 0 and 1
• Bands must have same dimensions
• Division by zero handling

Preprocessing

clip_raster(image_path: Path, shapefile_path: Path) -> np.ndarray

Clips a raster image using a shapefile.

Parameters:

• image_path: Path to raster file
• shapefile_path: Path to clipping shapefile

Returns:

• NumPy array with clipped image

Validations:

• Files must exist
• Compatible coordinate systems
• Valid clipping area

Logging and Traceability

setup_logging(output_dir: Path) -> None

Configures the logging system according to ISO 42001.

Parameters:

• output_dir: Directory for log files

Features:

• Precise timestamps
• Automatic backup
• SHA-256 integrity verification
• Log rotation

Configuration

get_config() -> Dict[str, Any]

Returns the current system configuration.

Returns:

• Dictionary with configuration values

Configurable Parameters:

• Working directories
• Supported indices
• Security limits
• Satellite configuration

Error Handling

All functions implement:

• Input validation
• Descriptive error messages
• Error logging
• Traceability according to ISO 42001

Usage Examples

from pathlib import Path
from src.indices import calculate_ndvi
from src.preprocessor import clip_raster
from src.logging_config import setup_logging

# Configurar logging
setup_logging(Path("results"))

# Procesar imagen
red = clip_raster("imagen.tif", "area.shp")
nir = clip_raster("imagen_nir.tif", "area.shp")
ndvi = calculate_ndvi(red, nir)

Implementation Notes

• All functions are thread-safe
• Optimized for large datasets
• Implement efficient memory management
• Comply with static typing