Function project_onto_path 

pub fn project_onto_path(
    gnss_positions: &[GnssPosition],
    path: &TrainPath,
    netelements: &[Netelement],
    _config: &PathConfig,
) -> Result<Vec<ProjectedPosition>, ProjectionError>

Project GNSS coordinates onto a calculated train path (US2: T093-T097)

Projects each GNSS position onto the nearest segment in the provided path, calculating intrinsic coordinates (0-1 range) for each position.

Arguments

• gnss_positions - Vector of GNSS positions to project
• path - Pre-calculated train path (from calculate_train_path or loaded from file)
• netelements - Railway network elements (needed for geometry)
• config - Path configuration (not currently used, reserved for future)

Returns

Vector of ProjectedPosition structs, one per GNSS coordinate

Errors

Returns ProjectionError if:

• GNSS positions or path is empty
• Netelement IDs in path don’t exist in netelements collection
• Projection onto linestring fails
• Intrinsic coordinates fall outside valid range [0, 1]

Example

use tp_lib_core::{project_onto_path, PathConfig};
use tp_lib_core::models::{GnssPosition, TrainPath, Netelement};

// Load pre-calculated path
let path: TrainPath = todo!(); // From file or calculate_train_path
let netelements: Vec<Netelement> = todo!();
let gnss_positions: Vec<GnssPosition> = todo!();

let config = PathConfig::default();
let projected = project_onto_path(&gnss_positions, &path, &netelements, &config)?;

// Each projected position has netelement_id and intrinsic coordinate
for proj in projected {
    if let Some(intrinsic) = proj.intrinsic {
        println!("Projected to {} at intrinsic {:.3}", proj.netelement_id, intrinsic);
    }
}