The nfo/grf Technical Reference

Variational Action 2 Variables for Canals


VariableVersionSizeContent
80 BHeight above ground, top parts of locks have the same height as the lower parts.
81 BTerrain type: 0 normal, 1 desert, 2 rainforest, 4 on or above snowline
822.5 r2367, OTTD r25229BDike map
832.6 r1562BRandom byte for plain canals and river tiles, otherwise zero (e.g., under bridges or for old savegames)

Variational Actions 2 are available for IDs 0/1/2/5/6 (watercliffs, locks, dikes, river slopes, river watersides)

Dike map (82)

This variable returns the sides and edges at which the water tile has a dike, i.e. no connection to another water tile. The variable is a bitset with each single bit indicating a dike towards the eight adjacent tiles:

BitValueDirection
01NE
12SE
24SW
38NW
416E
532S
664W
7128N