Estonian Land Board map sheet (grid) index formulas / Maa-ameti kaardilehtede järjekorranumbrite teisendusvalemid

elb_grids.py

# x - easting, y - northing

def grid20k(x, y):
    x = int(x) // 1000 - 200
    y = int(y) // 1000 - 5900
    idx = (y // 100) * 1000 + (y // 10 % 10) * 10
    idx += (x // 100) * 100 + (x // 10 % 10)
    return idx

def grid10k(x, y):
    idx = grid20k(x, y) * 10
    idx += (int(y) // 5000 % 2) * 2
    idx += (int(x) // 5000 % 2) + 1
    return idx

def grid2k(x, y):
    return (int(y / 1000) - 6000) * 1000 + int(x / 1000)

def decode_grid20k(idx):
    x = ((idx // 100) % 10) * 10
    x += idx % 10
    y = (idx // 1000) * 10
    y += (idx // 10) % 10
    return (x + 20) * 10000, (y + 590) * 10000

def decode_grid10k(idx):
    x, y = decode_grid20k(idx // 10)
    sub_idx = idx % 10 - 1
    x += (sub_idx % 2) * 5000
    y += (sub_idx // 2) * 5000
    return x, y

def decode_grid2k(idx):
    return idx % 1000 * 1000, (idx // 1000 + 6000) * 1000