# Compute the availability coefficient based on these coefficients:
# IUCN Protected Areas Categories System:
# Ia Strict Nature Reserve              0%   0
# Ib Wilderness Area                    10%  5            
# II National Park                      80% 30
# III Natural Monument or Feature       10%  5
# IV Habitat/Species Management Area    10%  5
# V Protected Landscape/ Seascape       90% 50
# VI Protected area with sustainable use of natural resources 95% 60
# Altimetry:
# < 500              100% 
# 500-1000           90%  
# 1000-2000          70%  
# > 2000             30%


if(dtm_nonulls < 500, 
  1*( 
    0.0 *cdda_1a_r8km+ 
    0.05*cdda_1b_r8km+ 
    0.3 *cdda_2_r8km+ 
    0.05*cdda_3_r8km+ 
    0.05*cdda_4_r8km+ 
    0.5 *cdda_5_r8km+ 
    0.50*cdda_6_r8km+
    1*(64000000-cdda_1a_r8km-cdda_1b_r8km-cdda_2_r8km-cdda_3_r8km-cdda_4_r8km-cdda_5_r8km-cdda_6_r8km) )/64000000, 
  if(dtm_nonulls < 1000, 
    0.9*( 
    0.0 *cdda_1a_r8km+ 
    0.05*cdda_1b_r8km+ 
    0.3 *cdda_2_r8km+ 
    0.05*cdda_3_r8km+ 
    0.05*cdda_4_r8km+ 
    0.5 *cdda_5_r8km+ 
    0.50*cdda_6_r8km+
    1*(64000000-cdda_1a_r8km-cdda_1b_r8km-cdda_2_r8km-cdda_3_r8km-cdda_4_r8km-cdda_5_r8km-cdda_6_r8km) 
  )/64000000, 
  if(dtm_nonulls < 2000, 
    0.7*( 
    0.0 *cdda_1a_r8km+ 
    0.05*cdda_1b_r8km+ 
    0.3 *cdda_2_r8km+ 
    0.05*cdda_3_r8km+ 
    0.05*cdda_4_r8km+ 
    0.5 *cdda_5_r8km+ 
    0.50*cdda_6_r8km+
    1*(64000000-cdda_1a_r8km-cdda_1b_r8km-cdda_2_r8km-cdda_3_r8km-cdda_4_r8km-cdda_5_r8km-cdda_6_r8km) 
  )/64000000, 
    0.3*( 
    0.0 *cdda_1a_r8km+ 
    0.05*cdda_1b_r8km+ 
    0.3 *cdda_2_r8km+ 
    0.05*cdda_3_r8km+ 
    0.05*cdda_4_r8km+ 
    0.5 *cdda_5_r8km+ 
    0.50*cdda_6_r8km+
    1*(64000000-cdda_1a_r8km-cdda_1b_r8km-cdda_2_r8km-cdda_3_r8km-cdda_4_r8km-cdda_5_r8km-cdda_6_r8km) 
  )/64000000 
  )))
