{exp:taxonomy:nav template_path="{segment_1}/{segment_2}"}

gistfile1.txt

	// --------------------------------------------------------------------

	/**
	 * Returns the first node_id for a given template path
	 * @param string template_path
	 * @return int node_id,
	 * but if no rows returned, false
	 */
	function get_node_id_from_template_path($template_path)
	{
		$template_path= explode('/', trim($template_path, '/'));
		
		// note: if there is no second segment, default to 'index'
		list($template_group, $template) = $template_path + Array( 1 => 'index' );
		
		// Is the first segment the name of a template group?
		$this->EE->db->select('group_id');
		$this->EE->db->where('group_name', $template_group);
		$this->EE->db->where('site_id', $this->EE->config->item('site_id'));
		$query = $this->EE->db->get('template_groups');
		
		// Template group found!
		if ($query->num_rows() == 1)
		{	
			// Set the group_id so we can use it in the next query
			$group_id = $query->row('group_id');
	
			// Is the second segment the name of a valid template?
			$this->EE->db->select('template_id');
			$this->EE->db->where('group_id', $group_id);
			$this->EE->db->where('template_name', $template);
			$this->EE->db->where('site_id', $this->EE->config->item('site_id'));
			$query = $this->EE->db->get('templates');
		
			// We have a template id!
			if ($query->num_rows() == 1)
			{
				$template_id = $query->row('template_id');
				
				// now we can grab the Taxonomy node
				$this->EE->db->select('node_id');
				$this->EE->db->order_by($this->left_col, 'asc');
				$this->EE->db->limit(1); // we only want the first node found - in case multiple nodes point to same template path
				$this->EE->db->where('template_path', $template_id);
				$node = $this->EE->db->get($this->tree_table)->row_array(); 
				
				if($node)
        			{
					return $node['node_id'];
				}
				else
				{
					return false;
				}	
			}
		}
		return false; 
	}