NavMesh.GetAreaFromName

Parameters

Returns

int Index if the specified area name exists, or -1 if no area type has the specified name.

Description

Returns the area index for a named NavMesh area type.

// NearestPointOnWater
using UnityEngine;
using UnityEngine.AI;

public class NearestPointOnWater : MonoBehaviour
{
    void Update()
    {
        // Find the nearest point on water.
        int waterMask = 1 << NavMesh.GetAreaFromName("water");
        NavMeshHit hit;
        if (NavMesh.SamplePosition(transform.position, out hit, 2.0f, waterMask))
        {
            Debug.DrawRay(hit.position, Vector3.up, Color.blue);
        }
    }
}

Additional resources: Areas and Costs to learn how to use different Area types.