# Author: Kouadio Laurent alias Daniel <etanoyau@gmail.com>
# License: LGPL-3.0
"""
pycsamt.gis.constants
Static GIS constants and lookup tables for pycsamt:
- UTM_ZONE_DESIGNATOR: letter -> [lon_min, lon_max]
- Ellipsoid parameters and conversion factors
- utm_letter_designator: latitude -> UTM zone letter
"""
import numpy as np
#
# UTM zone designator ranges: letter -> [min_longitude, max_longitude]
UTM_ZONE_DESIGNATOR = {
"X": [72, 84],
"W": [64, 72],
"V": [56, 64],
"U": [48, 56],
"T": [40, 48],
"S": [32, 40],
"R": [24, 32],
"Q": [16, 24],
"P": [8, 16],
"N": [0, 8],
"M": [-8, 0],
"L": [-16, -8],
"K": [-24, -16],
"J": [-32, -24],
"H": [-40, -32],
"G": [-48, -40],
"F": [-56, -48],
"E": [-64, -56],
"D": [-72, -64],
"C": [-80, -72],
"Z": [-80, 84],
}
# Conversion constants
# -
DEG2RAD = np.pi / 180.0
RAD2DEG = 180.0 / np.pi
# Indices for ellipsoid parameter tuples
_EQUATORIAL_RADIUS_IDX = 2
_ECC_SQUARED_IDX = 3
# EPSG Proj4 string to zone mapping (spatialreference.org)
EPSG_PROJ4 = {
28350: [
"+proj=utm +zone=50 +south +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs",
50,
],
28351: [
"+proj=utm +zone=51 +south +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs",
51,
],
28352: [
"+proj=utm +zone=52 +south +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs",
52,
],
28353: [
"+proj=utm +zone=53 +south +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs",
53,
],
28354: [
"+proj=utm +zone=54 +south +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs",
54,
],
28355: [
"+proj=utm +zone=55 +south +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs",
55,
],
28356: [
"+proj=utm +zone=56 +south +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs",
56,
],
3112: [
"+proj=lcc +lat_1=-18 +lat_2=-36 +lat_0=0 +lon_0=134 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs",
0,
],
4326: ["+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs", 0],
32609: [
"+proj=utm +zone=9 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
9,
],
32610: [
"+proj=utm +zone=10 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
10,
],
32611: [
"+proj=utm +zone=11 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
11,
],
32612: [
"+proj=utm +zone=12 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
12,
],
32613: [
"+proj=utm +zone=13 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
13,
],
32614: [
"+proj=utm +zone=14 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
14,
],
32615: [
"+proj=utm +zone=15 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
15,
],
32616: [
"+proj=utm +zone=16 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
16,
],
32617: [
"+proj=utm +zone=17 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
17,
],
32618: [
"+proj=utm +zone=18 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
18,
],
32619: [
"+proj=utm +zone=19 +ellps=WGS84 +datum=WGS84 +units=m +no_defs",
19,
],
}
# Reference ellipsoids: [id, name, equatorial_radius (m), eccentricity_squared]
ELLIPSOIDS = [
[-1, "Placeholder", 0, 0],
[1, "Airy", 6377563.396, 0.00667054],
[2, "Australian National", 6378160.000, 0.006694542],
[3, "Bessel 1841", 6377397.155, 0.006674372],
[4, "Bessel 1841 (Namibia)", 6377484.000, 0.006674372],
[5, "Clarke 1866", 6378206.400, 0.006768658],
[6, "Clarke 1880", 6378249.145, 0.006803511],
[7, "Everest", 6377276.345, 0.006637847],
[8, "Fischer 1960 (Mercury)", 6378166.000, 0.006693422],
[9, "Fischer 1968", 6378150.000, 0.006693422],
[10, "GRS 1967", 6378160.000, 0.006694605],
[11, "GRS 1980", 6378137.000, 0.006694380],
[12, "Helmert 1906", 6378200.000, 0.006693422],
[13, "Hough", 6378270.000, 0.006722670],
[14, "International", 6378388.000, 0.006722670],
[15, "Krassovsky", 6378245.000, 0.006693422],
[16, "Modified Airy", 6377340.000, 0.006670540],
[17, "Modified Everest", 6377304.000, 0.006637847],
[18, "Modified Fischer 1960", 6378155.000, 0.006693422],
[19, "South American 1969", 6378160.000, 0.006694542],
[20, "WGS 60", 6378165.000, 0.006693422],
[21, "WGS 66", 6378145.000, 0.006694542],
[22, "WGS-72", 6378135.000, 0.006694318],
[23, "WGS-84", 6378137.000, 0.006694380],
]
# UTM letter designator by latitude
[docs]
def utm_letter_designator(lat: float) -> str:
"""
Returns the UTM zone letter for a given latitude.
'Z' if latitude outside 80°S to 84°N.
"""
if 84 >= lat >= 72:
return "X"
elif 72 > lat >= 64:
return "W"
elif 64 > lat >= 56:
return "V"
elif 56 > lat >= 48:
return "U"
elif 48 > lat >= 40:
return "T"
elif 40 > lat >= 32:
return "S"
elif 32 > lat >= 24:
return "R"
elif 24 > lat >= 16:
return "Q"
elif 16 > lat >= 8:
return "P"
elif 8 > lat >= 0:
return "N"
elif 0 > lat >= -8:
return "M"
elif -8 > lat >= -16:
return "L"
elif -16 > lat >= -24:
return "K"
elif -24 > lat >= -32:
return "J"
elif -32 > lat >= -40:
return "H"
elif -40 > lat >= -48:
return "G"
elif -48 > lat >= -56:
return "F"
elif -56 > lat >= -64:
return "E"
elif -64 > lat >= -72:
return "D"
elif -72 > lat >= -80:
return "C"
else:
return "Z"
__all__ = [
"UTM_ZONE_DESIGNATOR",
"DEG2RAD",
"RAD2DEG",
"ELLIPSOIDS",
"EPSG_PROJ4",
"_ECC_SQUARED_IDX",
"_EQUATORIAL_RADIUS_IDX",
"utm_letter_designator",
]
