raster-marching-squares
Version:
Create isobands and isolines directly from a Raster with the marching-squares algorithm
1,255 lines (1,137 loc) • 134 kB
JavaScript
// https://github.com/rveciana/raster-marching-squares#readme Version 0.1.3. Copyright 2019 Roger Veciana i Rovira.
(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
typeof define === 'function' && define.amd ? define(['exports'], factory) :
(global = global || self, factory(global.rastertools = {}));
}(this, function (exports) { 'use strict';
var isobands = function(data, geoTransform, intervals){
var bands = { "type": "FeatureCollection",
"features": []
};
for(var i=1; i<intervals.length; i++){
var lowerValue = intervals[i-1];
var upperValue = intervals[i];
var coords = projectedIsoband(data, geoTransform, lowerValue, upperValue - lowerValue);
//Change clockwise
for(var j=0; j< coords.length; j++)
coords[j].reverse();
bands['features'].push({"type": "Feature",
"geometry": {
"type": "Polygon",
"coordinates": coords},
"properties": [{"lowerValue": lowerValue, "upperValue": upperValue}]}
);
}
return bands;
};
var projectedIsoband = function(data, geoTransform, minV, bandwidth){
if(typeof(geoTransform) != typeof(new Array()) || geoTransform.length != 6)
throw new Error("GeoTransform must be a 6 elements array");
var coords = isoband(data, minV, bandwidth);
for(var i = 0; i<coords.length; i++){
for(var j = 0; j<coords[i].length; j++){
var coordsGeo = applyGeoTransform(coords[i][j][0], coords[i][j][1], geoTransform);
coords[i][j][0]= coordsGeo[0];
coords[i][j][1]= coordsGeo[1];
}
}
return coords;
};
/**
Xgeo = GT(0) + Xpixel*GT(1) + Yline*GT(2)
Ygeo = GT(3) + Xpixel*GT(4) + Yline*GT(5)
*/
var applyGeoTransform = function(x, y, geoTransform){
var xgeo = geoTransform[0] + x*geoTransform[1] + y*geoTransform[2];
var ygeo = geoTransform[3] + x*geoTransform[4] + y*geoTransform[5];
return [xgeo, ygeo];
};
/*
Compute isobands(s) of a scalar 2D field given a certain
threshold and a bandwidth by applying the Marching Squares
Algorithm. The function returns a list of path coordinates
either for individual polygons within each grid cell, or the
outline of connected polygons.
*/
var isoband = function(data, minV, bandwidth, options){
var settings = {};
var defaultSettings = {
successCallback: null,
progressCallback: null,
verbose: false
};
/* process options */
options = options ? options : {};
var optionKeys = Object.keys(defaultSettings);
for(var i = 0; i < optionKeys.length; i++){
var key = optionKeys[i];
var val = options[key];
val = ((typeof val !== 'undefined') && (val !== null)) ? val : defaultSettings[key];
settings[key] = val;
}
if(settings.verbose)
console.log("computing isobands for [" + minV + ":" + (minV + bandwidth) + "]");
var grid = computeBandGrid(data, minV, bandwidth);
var ret = BandGrid2AreaPaths(grid);
return ret;
};
/*
Thats all for the public interface, below follows the actual
implementation
*/
/* Some private variables */
var Node0 = 64,
Node1 = 16,
Node2 = 4,
Node3 = 1;
/* For isoBands, each square is defined by the three states
of its corner points. However, since computers use power-2
values, we use 2bits per trit, i.e.:
00 ... below minV
01 ... between minV and maxV
10 ... above maxV
Hence we map the 4-trit configurations as follows:
0000 => 0
0001 => 1
0002 => 2
0010 => 4
0011 => 5
0012 => 6
0020 => 8
0021 => 9
0022 => 10
0100 => 16
0101 => 17
0102 => 18
0110 => 20
0111 => 21
0112 => 22
0120 => 24
0121 => 25
0122 => 26
0200 => 32
0201 => 33
0202 => 34
0210 => 36
0211 => 37
0212 => 38
0220 => 40
0221 => 41
0222 => 42
1000 => 64
1001 => 65
1002 => 66
1010 => 68
1011 => 69
1012 => 70
1020 => 72
1021 => 73
1022 => 74
1100 => 80
1101 => 81
1102 => 82
1110 => 84
1111 => 85
1112 => 86
1120 => 88
1121 => 89
1122 => 90
1200 => 96
1201 => 97
1202 => 98
1210 => 100
1211 => 101
1212 => 102
1220 => 104
1221 => 105
1222 => 106
2000 => 128
2001 => 129
2002 => 130
2010 => 132
2011 => 133
2012 => 134
2020 => 136
2021 => 137
2022 => 138
2100 => 144
2101 => 145
2102 => 146
2110 => 148
2111 => 149
2112 => 150
2120 => 152
2121 => 153
2122 => 154
2200 => 160
2201 => 161
2202 => 162
2210 => 164
2211 => 165
2212 => 166
2220 => 168
2221 => 169
2222 => 170
*/
/*
The look-up tables for tracing back the contour path
of isoBands
*/
var isoBandNextXTL = [];
var isoBandNextYTL = [];
var isoBandNextOTL = [];
var isoBandNextXTR = [];
var isoBandNextYTR = [];
var isoBandNextOTR = [];
var isoBandNextXRT = [];
var isoBandNextYRT = [];
var isoBandNextORT = [];
var isoBandNextXRB = [];
var isoBandNextYRB = [];
var isoBandNextORB = [];
var isoBandNextXBL = [];
var isoBandNextYBL = [];
var isoBandNextOBL = [];
var isoBandNextXBR = [];
var isoBandNextYBR = [];
var isoBandNextOBR = [];
var isoBandNextXLT = [];
var isoBandNextYLT = [];
var isoBandNextOLT = [];
var isoBandNextXLB = [];
var isoBandNextYLB = [];
var isoBandNextOLB = [];
isoBandNextXRT[85] = isoBandNextXRB[85] = -1;
isoBandNextYRT[85] = isoBandNextYRB[85] = 0;
isoBandNextORT[85] = isoBandNextORB[85] = 1;
isoBandNextXLT[85] = isoBandNextXLB[85] = 1;
isoBandNextYLT[85] = isoBandNextYLB[85] = 0;
isoBandNextOLT[85] = isoBandNextOLB[85] = 1;
isoBandNextXTL[85] = isoBandNextXTR[85] = 0;
isoBandNextYTL[85] = isoBandNextYTR[85] = -1;
isoBandNextOTL[85] = isoBandNextOBL[85] = 0;
isoBandNextXBR[85] = isoBandNextXBL[85] = 0;
isoBandNextYBR[85] = isoBandNextYBL[85] = 1;
isoBandNextOTR[85] = isoBandNextOBR[85] = 1;
/* triangle cases */
isoBandNextXLB[1] = isoBandNextXLB[169] = 0;
isoBandNextYLB[1] = isoBandNextYLB[169] = -1;
isoBandNextOLB[1] = isoBandNextOLB[169] = 0;
isoBandNextXBL[1] = isoBandNextXBL[169] = -1;
isoBandNextYBL[1] = isoBandNextYBL[169] = 0;
isoBandNextOBL[1] = isoBandNextOBL[169] = 0;
isoBandNextXRB[4] = isoBandNextXRB[166] = 0;
isoBandNextYRB[4] = isoBandNextYRB[166] = -1;
isoBandNextORB[4] = isoBandNextORB[166] = 1;
isoBandNextXBR[4] = isoBandNextXBR[166] = 1;
isoBandNextYBR[4] = isoBandNextYBR[166] = 0;
isoBandNextOBR[4] = isoBandNextOBR[166] = 0;
isoBandNextXRT[16] = isoBandNextXRT[154] = 0;
isoBandNextYRT[16] = isoBandNextYRT[154] = 1;
isoBandNextORT[16] = isoBandNextORT[154] = 1;
isoBandNextXTR[16] = isoBandNextXTR[154] = 1;
isoBandNextYTR[16] = isoBandNextYTR[154] = 0;
isoBandNextOTR[16] = isoBandNextOTR[154] = 1;
isoBandNextXLT[64] = isoBandNextXLT[106] = 0;
isoBandNextYLT[64] = isoBandNextYLT[106] = 1;
isoBandNextOLT[64] = isoBandNextOLT[106] = 0;
isoBandNextXTL[64] = isoBandNextXTL[106] = -1;
isoBandNextYTL[64] = isoBandNextYTL[106] = 0;
isoBandNextOTL[64] = isoBandNextOTL[106] = 1;
/* single trapezoid cases */
isoBandNextXLT[2] = isoBandNextXLT[168] = 0;
isoBandNextYLT[2] = isoBandNextYLT[168] = -1;
isoBandNextOLT[2] = isoBandNextOLT[168] = 1;
isoBandNextXLB[2] = isoBandNextXLB[168] = 0;
isoBandNextYLB[2] = isoBandNextYLB[168] = -1;
isoBandNextOLB[2] = isoBandNextOLB[168] = 0;
isoBandNextXBL[2] = isoBandNextXBL[168] = -1;
isoBandNextYBL[2] = isoBandNextYBL[168] = 0;
isoBandNextOBL[2] = isoBandNextOBL[168] = 0;
isoBandNextXBR[2] = isoBandNextXBR[168] = -1;
isoBandNextYBR[2] = isoBandNextYBR[168] = 0;
isoBandNextOBR[2] = isoBandNextOBR[168] = 1;
isoBandNextXRT[8] = isoBandNextXRT[162] = 0;
isoBandNextYRT[8] = isoBandNextYRT[162] = -1;
isoBandNextORT[8] = isoBandNextORT[162] = 0;
isoBandNextXRB[8] = isoBandNextXRB[162] = 0;
isoBandNextYRB[8] = isoBandNextYRB[162] = -1;
isoBandNextORB[8] = isoBandNextORB[162] = 1;
isoBandNextXBL[8] = isoBandNextXBL[162] = 1;
isoBandNextYBL[8] = isoBandNextYBL[162] = 0;
isoBandNextOBL[8] = isoBandNextOBL[162] = 1;
isoBandNextXBR[8] = isoBandNextXBR[162] = 1;
isoBandNextYBR[8] = isoBandNextYBR[162] = 0;
isoBandNextOBR[8] = isoBandNextOBR[162] = 0;
isoBandNextXRT[32] = isoBandNextXRT[138] = 0;
isoBandNextYRT[32] = isoBandNextYRT[138] = 1;
isoBandNextORT[32] = isoBandNextORT[138] = 1;
isoBandNextXRB[32] = isoBandNextXRB[138] = 0;
isoBandNextYRB[32] = isoBandNextYRB[138] = 1;
isoBandNextORB[32] = isoBandNextORB[138] = 0;
isoBandNextXTL[32] = isoBandNextXTL[138] = 1;
isoBandNextYTL[32] = isoBandNextYTL[138] = 0;
isoBandNextOTL[32] = isoBandNextOTL[138] = 0;
isoBandNextXTR[32] = isoBandNextXTR[138] = 1;
isoBandNextYTR[32] = isoBandNextYTR[138] = 0;
isoBandNextOTR[32] = isoBandNextOTR[138] = 1;
isoBandNextXLB[128] = isoBandNextXLB[42] = 0;
isoBandNextYLB[128] = isoBandNextYLB[42] = 1;
isoBandNextOLB[128] = isoBandNextOLB[42] = 1;
isoBandNextXLT[128] = isoBandNextXLT[42] = 0;
isoBandNextYLT[128] = isoBandNextYLT[42] = 1;
isoBandNextOLT[128] = isoBandNextOLT[42] = 0;
isoBandNextXTL[128] = isoBandNextXTL[42] = -1;
isoBandNextYTL[128] = isoBandNextYTL[42] = 0;
isoBandNextOTL[128] = isoBandNextOTL[42] = 1;
isoBandNextXTR[128] = isoBandNextXTR[42] = -1;
isoBandNextYTR[128] = isoBandNextYTR[42] = 0;
isoBandNextOTR[128] = isoBandNextOTR[42] = 0;
/* single rectangle cases */
isoBandNextXRB[5] = isoBandNextXRB[165] = -1;
isoBandNextYRB[5] = isoBandNextYRB[165] = 0;
isoBandNextORB[5] = isoBandNextORB[165] = 0;
isoBandNextXLB[5] = isoBandNextXLB[165] = 1;
isoBandNextYLB[5] = isoBandNextYLB[165] = 0;
isoBandNextOLB[5] = isoBandNextOLB[165] = 0;
isoBandNextXBR[20] = isoBandNextXBR[150] = 0;
isoBandNextYBR[20] = isoBandNextYBR[150] = 1;
isoBandNextOBR[20] = isoBandNextOBR[150] = 1;
isoBandNextXTR[20] = isoBandNextXTR[150] = 0;
isoBandNextYTR[20] = isoBandNextYTR[150] = -1;
isoBandNextOTR[20] = isoBandNextOTR[150] = 1;
isoBandNextXRT[80] = isoBandNextXRT[90] = -1;
isoBandNextYRT[80] = isoBandNextYRT[90] = 0;
isoBandNextORT[80] = isoBandNextORT[90] = 1;
isoBandNextXLT[80] = isoBandNextXLT[90] = 1;
isoBandNextYLT[80] = isoBandNextYLT[90] = 0;
isoBandNextOLT[80] = isoBandNextOLT[90] = 1;
isoBandNextXBL[65] = isoBandNextXBL[105] = 0;
isoBandNextYBL[65] = isoBandNextYBL[105] = 1;
isoBandNextOBL[65] = isoBandNextOBL[105] = 0;
isoBandNextXTL[65] = isoBandNextXTL[105] = 0;
isoBandNextYTL[65] = isoBandNextYTL[105] = -1;
isoBandNextOTL[65] = isoBandNextOTL[105] = 0;
isoBandNextXRT[160] = isoBandNextXRT[10] = -1;
isoBandNextYRT[160] = isoBandNextYRT[10] = 0;
isoBandNextORT[160] = isoBandNextORT[10] = 1;
isoBandNextXRB[160] = isoBandNextXRB[10] = -1;
isoBandNextYRB[160] = isoBandNextYRB[10] = 0;
isoBandNextORB[160] = isoBandNextORB[10] = 0;
isoBandNextXLB[160] = isoBandNextXLB[10] = 1;
isoBandNextYLB[160] = isoBandNextYLB[10] = 0;
isoBandNextOLB[160] = isoBandNextOLB[10] = 0;
isoBandNextXLT[160] = isoBandNextXLT[10] = 1;
isoBandNextYLT[160] = isoBandNextYLT[10] = 0;
isoBandNextOLT[160] = isoBandNextOLT[10] = 1;
isoBandNextXBR[130] = isoBandNextXBR[40] = 0;
isoBandNextYBR[130] = isoBandNextYBR[40] = 1;
isoBandNextOBR[130] = isoBandNextOBR[40] = 1;
isoBandNextXBL[130] = isoBandNextXBL[40] = 0;
isoBandNextYBL[130] = isoBandNextYBL[40] = 1;
isoBandNextOBL[130] = isoBandNextOBL[40] = 0;
isoBandNextXTL[130] = isoBandNextXTL[40] = 0;
isoBandNextYTL[130] = isoBandNextYTL[40] = -1;
isoBandNextOTL[130] = isoBandNextOTL[40] = 0;
isoBandNextXTR[130] = isoBandNextXTR[40] = 0;
isoBandNextYTR[130] = isoBandNextYTR[40] = -1;
isoBandNextOTR[130] = isoBandNextOTR[40] = 1;
/* single hexagon cases */
isoBandNextXRB[37] = isoBandNextXRB[133] = 0;
isoBandNextYRB[37] = isoBandNextYRB[133] = 1;
isoBandNextORB[37] = isoBandNextORB[133] = 1;
isoBandNextXLB[37] = isoBandNextXLB[133] = 0;
isoBandNextYLB[37] = isoBandNextYLB[133] = 1;
isoBandNextOLB[37] = isoBandNextOLB[133] = 0;
isoBandNextXTL[37] = isoBandNextXTL[133] = -1;
isoBandNextYTL[37] = isoBandNextYTL[133] = 0;
isoBandNextOTL[37] = isoBandNextOTL[133] = 0;
isoBandNextXTR[37] = isoBandNextXTR[133] = 1;
isoBandNextYTR[37] = isoBandNextYTR[133] = 0;
isoBandNextOTR[37] = isoBandNextOTR[133] = 0;
isoBandNextXBR[148] = isoBandNextXBR[22] = -1;
isoBandNextYBR[148] = isoBandNextYBR[22] = 0;
isoBandNextOBR[148] = isoBandNextOBR[22] = 0;
isoBandNextXLB[148] = isoBandNextXLB[22] = 0;
isoBandNextYLB[148] = isoBandNextYLB[22] = -1;
isoBandNextOLB[148] = isoBandNextOLB[22] = 1;
isoBandNextXLT[148] = isoBandNextXLT[22] = 0;
isoBandNextYLT[148] = isoBandNextYLT[22] = 1;
isoBandNextOLT[148] = isoBandNextOLT[22] = 1;
isoBandNextXTR[148] = isoBandNextXTR[22] = -1;
isoBandNextYTR[148] = isoBandNextYTR[22] = 0;
isoBandNextOTR[148] = isoBandNextOTR[22] = 1;
isoBandNextXRT[82] = isoBandNextXRT[88] = 0;
isoBandNextYRT[82] = isoBandNextYRT[88] = -1;
isoBandNextORT[82] = isoBandNextORT[88] = 1;
isoBandNextXBR[82] = isoBandNextXBR[88] = 1;
isoBandNextYBR[82] = isoBandNextYBR[88] = 0;
isoBandNextOBR[82] = isoBandNextOBR[88] = 1;
isoBandNextXBL[82] = isoBandNextXBL[88] = -1;
isoBandNextYBL[82] = isoBandNextYBL[88] = 0;
isoBandNextOBL[82] = isoBandNextOBL[88] = 1;
isoBandNextXLT[82] = isoBandNextXLT[88] = 0;
isoBandNextYLT[82] = isoBandNextYLT[88] = -1;
isoBandNextOLT[82] = isoBandNextOLT[88] = 0;
isoBandNextXRT[73] = isoBandNextXRT[97] = 0;
isoBandNextYRT[73] = isoBandNextYRT[97] = 1;
isoBandNextORT[73] = isoBandNextORT[97] = 0;
isoBandNextXRB[73] = isoBandNextXRB[97] = 0;
isoBandNextYRB[73] = isoBandNextYRB[97] = -1;
isoBandNextORB[73] = isoBandNextORB[97] = 0;
isoBandNextXBL[73] = isoBandNextXBL[97] = 1;
isoBandNextYBL[73] = isoBandNextYBL[97] = 0;
isoBandNextOBL[73] = isoBandNextOBL[97] = 0;
isoBandNextXTL[73] = isoBandNextXTL[97] = 1;
isoBandNextYTL[73] = isoBandNextYTL[97] = 0;
isoBandNextOTL[73] = isoBandNextOTL[97] = 1;
isoBandNextXRT[145] = isoBandNextXRT[25] = 0;
isoBandNextYRT[145] = isoBandNextYRT[25] = -1;
isoBandNextORT[145] = isoBandNextORT[25] = 0;
isoBandNextXBL[145] = isoBandNextXBL[25] = 1;
isoBandNextYBL[145] = isoBandNextYBL[25] = 0;
isoBandNextOBL[145] = isoBandNextOBL[25] = 1;
isoBandNextXLB[145] = isoBandNextXLB[25] = 0;
isoBandNextYLB[145] = isoBandNextYLB[25] = 1;
isoBandNextOLB[145] = isoBandNextOLB[25] = 1;
isoBandNextXTR[145] = isoBandNextXTR[25] = -1;
isoBandNextYTR[145] = isoBandNextYTR[25] = 0;
isoBandNextOTR[145] = isoBandNextOTR[25] = 0;
isoBandNextXRB[70] = isoBandNextXRB[100] = 0;
isoBandNextYRB[70] = isoBandNextYRB[100] = 1;
isoBandNextORB[70] = isoBandNextORB[100] = 0;
isoBandNextXBR[70] = isoBandNextXBR[100] = -1;
isoBandNextYBR[70] = isoBandNextYBR[100] = 0;
isoBandNextOBR[70] = isoBandNextOBR[100] = 1;
isoBandNextXLT[70] = isoBandNextXLT[100] = 0;
isoBandNextYLT[70] = isoBandNextYLT[100] = -1;
isoBandNextOLT[70] = isoBandNextOLT[100] = 1;
isoBandNextXTL[70] = isoBandNextXTL[100] = 1;
isoBandNextYTL[70] = isoBandNextYTL[100] = 0;
isoBandNextOTL[70] = isoBandNextOTL[100] = 0;
/* single pentagon cases */
isoBandNextXRB[101] = isoBandNextXRB[69] = 0;
isoBandNextYRB[101] = isoBandNextYRB[69] = 1;
isoBandNextORB[101] = isoBandNextORB[69] = 0;
isoBandNextXTL[101] = isoBandNextXTL[69] = 1;
isoBandNextYTL[101] = isoBandNextYTL[69] = 0;
isoBandNextOTL[101] = isoBandNextOTL[69] = 0;
isoBandNextXLB[149] = isoBandNextXLB[21] = 0;
isoBandNextYLB[149] = isoBandNextYLB[21] = 1;
isoBandNextOLB[149] = isoBandNextOLB[21] = 1;
isoBandNextXTR[149] = isoBandNextXTR[21] = -1;
isoBandNextYTR[149] = isoBandNextYTR[21] = 0;
isoBandNextOTR[149] = isoBandNextOTR[21] = 0;
isoBandNextXBR[86] = isoBandNextXBR[84] = -1;
isoBandNextYBR[86] = isoBandNextYBR[84] = 0;
isoBandNextOBR[86] = isoBandNextOBR[84] = 1;
isoBandNextXLT[86] = isoBandNextXLT[84] = 0;
isoBandNextYLT[86] = isoBandNextYLT[84] = -1;
isoBandNextOLT[86] = isoBandNextOLT[84] = 1;
isoBandNextXRT[89] = isoBandNextXRT[81] = 0;
isoBandNextYRT[89] = isoBandNextYRT[81] = -1;
isoBandNextORT[89] = isoBandNextORT[81] = 0;
isoBandNextXBL[89] = isoBandNextXBL[81] = 1;
isoBandNextYBL[89] = isoBandNextYBL[81] = 0;
isoBandNextOBL[89] = isoBandNextOBL[81] = 1;
isoBandNextXRT[96] = isoBandNextXRT[74] = 0;
isoBandNextYRT[96] = isoBandNextYRT[74] = 1;
isoBandNextORT[96] = isoBandNextORT[74] = 0;
isoBandNextXRB[96] = isoBandNextXRB[74] = -1;
isoBandNextYRB[96] = isoBandNextYRB[74] = 0;
isoBandNextORB[96] = isoBandNextORB[74] = 1;
isoBandNextXLT[96] = isoBandNextXLT[74] = 1;
isoBandNextYLT[96] = isoBandNextYLT[74] = 0;
isoBandNextOLT[96] = isoBandNextOLT[74] = 0;
isoBandNextXTL[96] = isoBandNextXTL[74] = 1;
isoBandNextYTL[96] = isoBandNextYTL[74] = 0;
isoBandNextOTL[96] = isoBandNextOTL[74] = 1;
isoBandNextXRT[24] = isoBandNextXRT[146] = 0;
isoBandNextYRT[24] = isoBandNextYRT[146] = -1;
isoBandNextORT[24] = isoBandNextORT[146] = 1;
isoBandNextXBR[24] = isoBandNextXBR[146] = 1;
isoBandNextYBR[24] = isoBandNextYBR[146] = 0;
isoBandNextOBR[24] = isoBandNextOBR[146] = 1;
isoBandNextXBL[24] = isoBandNextXBL[146] = 0;
isoBandNextYBL[24] = isoBandNextYBL[146] = 1;
isoBandNextOBL[24] = isoBandNextOBL[146] = 1;
isoBandNextXTR[24] = isoBandNextXTR[146] = 0;
isoBandNextYTR[24] = isoBandNextYTR[146] = -1;
isoBandNextOTR[24] = isoBandNextOTR[146] = 0;
isoBandNextXRB[6] = isoBandNextXRB[164] = -1;
isoBandNextYRB[6] = isoBandNextYRB[164] = 0;
isoBandNextORB[6] = isoBandNextORB[164] = 1;
isoBandNextXBR[6] = isoBandNextXBR[164] = -1;
isoBandNextYBR[6] = isoBandNextYBR[164] = 0;
isoBandNextOBR[6] = isoBandNextOBR[164] = 0;
isoBandNextXLB[6] = isoBandNextXLB[164] = 0;
isoBandNextYLB[6] = isoBandNextYLB[164] = -1;
isoBandNextOLB[6] = isoBandNextOLB[164] = 1;
isoBandNextXLT[6] = isoBandNextXLT[164] = 1;
isoBandNextYLT[6] = isoBandNextYLT[164] = 0;
isoBandNextOLT[6] = isoBandNextOLT[164] = 0;
isoBandNextXBL[129] = isoBandNextXBL[41] = 0;
isoBandNextYBL[129] = isoBandNextYBL[41] = 1;
isoBandNextOBL[129] = isoBandNextOBL[41] = 1;
isoBandNextXLB[129] = isoBandNextXLB[41] = 0;
isoBandNextYLB[129] = isoBandNextYLB[41] = 1;
isoBandNextOLB[129] = isoBandNextOLB[41] = 0;
isoBandNextXTL[129] = isoBandNextXTL[41] = -1;
isoBandNextYTL[129] = isoBandNextYTL[41] = 0;
isoBandNextOTL[129] = isoBandNextOTL[41] = 0;
isoBandNextXTR[129] = isoBandNextXTR[41] = 0;
isoBandNextYTR[129] = isoBandNextYTR[41] = -1;
isoBandNextOTR[129] = isoBandNextOTR[41] = 0;
isoBandNextXBR[66] = isoBandNextXBR[104] = 0;
isoBandNextYBR[66] = isoBandNextYBR[104] = 1;
isoBandNextOBR[66] = isoBandNextOBR[104] = 0;
isoBandNextXBL[66] = isoBandNextXBL[104] = -1;
isoBandNextYBL[66] = isoBandNextYBL[104] = 0;
isoBandNextOBL[66] = isoBandNextOBL[104] = 1;
isoBandNextXLT[66] = isoBandNextXLT[104] = 0;
isoBandNextYLT[66] = isoBandNextYLT[104] = -1;
isoBandNextOLT[66] = isoBandNextOLT[104] = 0;
isoBandNextXTL[66] = isoBandNextXTL[104] = 0;
isoBandNextYTL[66] = isoBandNextYTL[104] = -1;
isoBandNextOTL[66] = isoBandNextOTL[104] = 1;
isoBandNextXRT[144] = isoBandNextXRT[26] = -1;
isoBandNextYRT[144] = isoBandNextYRT[26] = 0;
isoBandNextORT[144] = isoBandNextORT[26] = 0;
isoBandNextXLB[144] = isoBandNextXLB[26] = 1;
isoBandNextYLB[144] = isoBandNextYLB[26] = 0;
isoBandNextOLB[144] = isoBandNextOLB[26] = 1;
isoBandNextXLT[144] = isoBandNextXLT[26] = 0;
isoBandNextYLT[144] = isoBandNextYLT[26] = 1;
isoBandNextOLT[144] = isoBandNextOLT[26] = 1;
isoBandNextXTR[144] = isoBandNextXTR[26] = -1;
isoBandNextYTR[144] = isoBandNextYTR[26] = 0;
isoBandNextOTR[144] = isoBandNextOTR[26] = 1;
isoBandNextXRB[36] = isoBandNextXRB[134] = 0;
isoBandNextYRB[36] = isoBandNextYRB[134] = 1;
isoBandNextORB[36] = isoBandNextORB[134] = 1;
isoBandNextXBR[36] = isoBandNextXBR[134] = 0;
isoBandNextYBR[36] = isoBandNextYBR[134] = 1;
isoBandNextOBR[36] = isoBandNextOBR[134] = 0;
isoBandNextXTL[36] = isoBandNextXTL[134] = 0;
isoBandNextYTL[36] = isoBandNextYTL[134] = -1;
isoBandNextOTL[36] = isoBandNextOTL[134] = 1;
isoBandNextXTR[36] = isoBandNextXTR[134] = 1;
isoBandNextYTR[36] = isoBandNextYTR[134] = 0;
isoBandNextOTR[36] = isoBandNextOTR[134] = 0;
isoBandNextXRT[9] = isoBandNextXRT[161] = -1;
isoBandNextYRT[9] = isoBandNextYRT[161] = 0;
isoBandNextORT[9] = isoBandNextORT[161] = 0;
isoBandNextXRB[9] = isoBandNextXRB[161] = 0;
isoBandNextYRB[9] = isoBandNextYRB[161] = -1;
isoBandNextORB[9] = isoBandNextORB[161] = 0;
isoBandNextXBL[9] = isoBandNextXBL[161] = 1;
isoBandNextYBL[9] = isoBandNextYBL[161] = 0;
isoBandNextOBL[9] = isoBandNextOBL[161] = 0;
isoBandNextXLB[9] = isoBandNextXLB[161] = 1;
isoBandNextYLB[9] = isoBandNextYLB[161] = 0;
isoBandNextOLB[9] = isoBandNextOLB[161] = 1;
/* 8-sided cases */
isoBandNextXRT[136] = 0;
isoBandNextYRT[136] = 1;
isoBandNextORT[136] = 1;
isoBandNextXRB[136] = 0;
isoBandNextYRB[136] = 1;
isoBandNextORB[136] = 0;
isoBandNextXBR[136] = -1;
isoBandNextYBR[136] = 0;
isoBandNextOBR[136] = 1;
isoBandNextXBL[136] = -1;
isoBandNextYBL[136] = 0;
isoBandNextOBL[136] = 0;
isoBandNextXLB[136] = 0;
isoBandNextYLB[136] = -1;
isoBandNextOLB[136] = 0;
isoBandNextXLT[136] = 0;
isoBandNextYLT[136] = -1;
isoBandNextOLT[136] = 1;
isoBandNextXTL[136] = 1;
isoBandNextYTL[136] = 0;
isoBandNextOTL[136] = 0;
isoBandNextXTR[136] = 1;
isoBandNextYTR[136] = 0;
isoBandNextOTR[136] = 1;
isoBandNextXRT[34] = 0;
isoBandNextYRT[34] = -1;
isoBandNextORT[34] = 0;
isoBandNextXRB[34] = 0;
isoBandNextYRB[34] = -1;
isoBandNextORB[34] = 1;
isoBandNextXBR[34] = 1;
isoBandNextYBR[34] = 0;
isoBandNextOBR[34] = 0;
isoBandNextXBL[34] = 1;
isoBandNextYBL[34] = 0;
isoBandNextOBL[34] = 1;
isoBandNextXLB[34] = 0;
isoBandNextYLB[34] = 1;
isoBandNextOLB[34] = 1;
isoBandNextXLT[34] = 0;
isoBandNextYLT[34] = 1;
isoBandNextOLT[34] = 0;
isoBandNextXTL[34] = -1;
isoBandNextYTL[34] = 0;
isoBandNextOTL[34] = 1;
isoBandNextXTR[34] = -1;
isoBandNextYTR[34] = 0;
isoBandNextOTR[34] = 0;
isoBandNextXRT[35] = 0;
isoBandNextYRT[35] = 1;
isoBandNextORT[35] = 1;
isoBandNextXRB[35] = 0;
isoBandNextYRB[35] = -1;
isoBandNextORB[35] = 1;
isoBandNextXBR[35] = 1;
isoBandNextYBR[35] = 0;
isoBandNextOBR[35] = 0;
isoBandNextXBL[35] = -1;
isoBandNextYBL[35] = 0;
isoBandNextOBL[35] = 0;
isoBandNextXLB[35] = 0;
isoBandNextYLB[35] = -1;
isoBandNextOLB[35] = 0;
isoBandNextXLT[35] = 0;
isoBandNextYLT[35] = 1;
isoBandNextOLT[35] = 0;
isoBandNextXTL[35] = -1;
isoBandNextYTL[35] = 0;
isoBandNextOTL[35] = 1;
isoBandNextXTR[35] = 1;
isoBandNextYTR[35] = 0;
isoBandNextOTR[35] = 1;
/* 6-sided cases */
isoBandNextXRT[153] = 0;
isoBandNextYRT[153] = 1;
isoBandNextORT[153] = 1;
isoBandNextXBL[153] = -1;
isoBandNextYBL[153] = 0;
isoBandNextOBL[153] = 0;
isoBandNextXLB[153] = 0;
isoBandNextYLB[153] = -1;
isoBandNextOLB[153] = 0;
isoBandNextXTR[153] = 1;
isoBandNextYTR[153] = 0;
isoBandNextOTR[153] = 1;
isoBandNextXRB[102] = 0;
isoBandNextYRB[102] = -1;
isoBandNextORB[102] = 1;
isoBandNextXBR[102] = 1;
isoBandNextYBR[102] = 0;
isoBandNextOBR[102] = 0;
isoBandNextXLT[102] = 0;
isoBandNextYLT[102] = 1;
isoBandNextOLT[102] = 0;
isoBandNextXTL[102] = -1;
isoBandNextYTL[102] = 0;
isoBandNextOTL[102] = 1;
isoBandNextXRT[155] = 0;
isoBandNextYRT[155] = -1;
isoBandNextORT[155] = 0;
isoBandNextXBL[155] = 1;
isoBandNextYBL[155] = 0;
isoBandNextOBL[155] = 1;
isoBandNextXLB[155] = 0;
isoBandNextYLB[155] = 1;
isoBandNextOLB[155] = 1;
isoBandNextXTR[155] = -1;
isoBandNextYTR[155] = 0;
isoBandNextOTR[155] = 0;
isoBandNextXRB[103] = 0;
isoBandNextYRB[103] = 1;
isoBandNextORB[103] = 0;
isoBandNextXBR[103] = -1;
isoBandNextYBR[103] = 0;
isoBandNextOBR[103] = 1;
isoBandNextXLT[103] = 0;
isoBandNextYLT[103] = -1;
isoBandNextOLT[103] = 1;
isoBandNextXTL[103] = 1;
isoBandNextYTL[103] = 0;
isoBandNextOTL[103] = 0;
/* 7-sided cases */
isoBandNextXRT[152] = 0;
isoBandNextYRT[152] = 1;
isoBandNextORT[152] = 1;
isoBandNextXBR[152] = -1;
isoBandNextYBR[152] = 0;
isoBandNextOBR[152] = 1;
isoBandNextXBL[152] = -1;
isoBandNextYBL[152] = 0;
isoBandNextOBL[152] = 0;
isoBandNextXLB[152] = 0;
isoBandNextYLB[152] = -1;
isoBandNextOLB[152] = 0;
isoBandNextXLT[152] = 0;
isoBandNextYLT[152] = -1;
isoBandNextOLT[152] = 1;
isoBandNextXTR[152] = 1;
isoBandNextYTR[152] = 0;
isoBandNextOTR[152] = 1;
isoBandNextXRT[156] = 0;
isoBandNextYRT[156] = -1;
isoBandNextORT[156] = 1;
isoBandNextXBR[156] = 1;
isoBandNextYBR[156] = 0;
isoBandNextOBR[156] = 1;
isoBandNextXBL[156] = -1;
isoBandNextYBL[156] = 0;
isoBandNextOBL[156] = 0;
isoBandNextXLB[156] = 0;
isoBandNextYLB[156] = -1;
isoBandNextOLB[156] = 0;
isoBandNextXLT[156] = 0;
isoBandNextYLT[156] = 1;
isoBandNextOLT[156] = 1;
isoBandNextXTR[156] = -1;
isoBandNextYTR[156] = 0;
isoBandNextOTR[156] = 1;
isoBandNextXRT[137] = 0;
isoBandNextYRT[137] = 1;
isoBandNextORT[137] = 1;
isoBandNextXRB[137] = 0;
isoBandNextYRB[137] = 1;
isoBandNextORB[137] = 0;
isoBandNextXBL[137] = -1;
isoBandNextYBL[137] = 0;
isoBandNextOBL[137] = 0;
isoBandNextXLB[137] = 0;
isoBandNextYLB[137] = -1;
isoBandNextOLB[137] = 0;
isoBandNextXTL[137] = 1;
isoBandNextYTL[137] = 0;
isoBandNextOTL[137] = 0;
isoBandNextXTR[137] = 1;
isoBandNextYTR[137] = 0;
isoBandNextOTR[137] = 1;
isoBandNextXRT[139] = 0;
isoBandNextYRT[139] = 1;
isoBandNextORT[139] = 1;
isoBandNextXRB[139] = 0;
isoBandNextYRB[139] = -1;
isoBandNextORB[139] = 0;
isoBandNextXBL[139] = 1;
isoBandNextYBL[139] = 0;
isoBandNextOBL[139] = 0;
isoBandNextXLB[139] = 0;
isoBandNextYLB[139] = 1;
isoBandNextOLB[139] = 0;
isoBandNextXTL[139] = -1;
isoBandNextYTL[139] = 0;
isoBandNextOTL[139] = 0;
isoBandNextXTR[139] = 1;
isoBandNextYTR[139] = 0;
isoBandNextOTR[139] = 1;
isoBandNextXRT[98] = 0;
isoBandNextYRT[98] = -1;
isoBandNextORT[98] = 0;
isoBandNextXRB[98] = 0;
isoBandNextYRB[98] = -1;
isoBandNextORB[98] = 1;
isoBandNextXBR[98] = 1;
isoBandNextYBR[98] = 0;
isoBandNextOBR[98] = 0;
isoBandNextXBL[98] = 1;
isoBandNextYBL[98] = 0;
isoBandNextOBL[98] = 1;
isoBandNextXLT[98] = 0;
isoBandNextYLT[98] = 1;
isoBandNextOLT[98] = 0;
isoBandNextXTL[98] = -1;
isoBandNextYTL[98] = 0;
isoBandNextOTL[98] = 1;
isoBandNextXRT[99] = 0;
isoBandNextYRT[99] = 1;
isoBandNextORT[99] = 0;
isoBandNextXRB[99] = 0;
isoBandNextYRB[99] = -1;
isoBandNextORB[99] = 1;
isoBandNextXBR[99] = 1;
isoBandNextYBR[99] = 0;
isoBandNextOBR[99] = 0;
isoBandNextXBL[99] = -1;
isoBandNextYBL[99] = 0;
isoBandNextOBL[99] = 1;
isoBandNextXLT[99] = 0;
isoBandNextYLT[99] = -1;
isoBandNextOLT[99] = 0;
isoBandNextXTL[99] = 1;
isoBandNextYTL[99] = 0;
isoBandNextOTL[99] = 1;
isoBandNextXRB[38] = 0;
isoBandNextYRB[38] = -1;
isoBandNextORB[38] = 1;
isoBandNextXBR[38] = 1;
isoBandNextYBR[38] = 0;
isoBandNextOBR[38] = 0;
isoBandNextXLB[38] = 0;
isoBandNextYLB[38] = 1;
isoBandNextOLB[38] = 1;
isoBandNextXLT[38] = 0;
isoBandNextYLT[38] = 1;
isoBandNextOLT[38] = 0;
isoBandNextXTL[38] = -1;
isoBandNextYTL[38] = 0;
isoBandNextOTL[38] = 1;
isoBandNextXTR[38] = -1;
isoBandNextYTR[38] = 0;
isoBandNextOTR[38] = 0;
isoBandNextXRB[39] = 0;
isoBandNextYRB[39] = 1;
isoBandNextORB[39] = 1;
isoBandNextXBR[39] = -1;
isoBandNextYBR[39] = 0;
isoBandNextOBR[39] = 0;
isoBandNextXLB[39] = 0;
isoBandNextYLB[39] = -1;
isoBandNextOLB[39] = 1;
isoBandNextXLT[39] = 0;
isoBandNextYLT[39] = 1;
isoBandNextOLT[39] = 0;
isoBandNextXTL[39] = -1;
isoBandNextYTL[39] = 0;
isoBandNextOTL[39] = 1;
isoBandNextXTR[39] = 1;
isoBandNextYTR[39] = 0;
isoBandNextOTR[39] = 0;
/*
The lookup tables for edge number given the polygon
is entered at a specific location
*/
var isoBandEdgeRT = [];
var isoBandEdgeRB = [];
var isoBandEdgeBR = [];
var isoBandEdgeBL = [];
var isoBandEdgeLB = [];
var isoBandEdgeLT = [];
var isoBandEdgeTL = [];
var isoBandEdgeTR = [];
/* triangle cases */
isoBandEdgeBL[1] = isoBandEdgeLB[1] = 18;
isoBandEdgeBL[169] = isoBandEdgeLB[169] = 18;
isoBandEdgeBR[4] = isoBandEdgeRB[4] = 12;
isoBandEdgeBR[166] = isoBandEdgeRB[166] = 12;
isoBandEdgeRT[16] = isoBandEdgeTR[16] = 4;
isoBandEdgeRT[154] = isoBandEdgeTR[154] = 4;
isoBandEdgeLT[64] = isoBandEdgeTL[64] = 22;
isoBandEdgeLT[106] = isoBandEdgeTL[106] = 22;
/* trapezoid cases */
isoBandEdgeBR[2] = isoBandEdgeLT[2] = 17;
isoBandEdgeBL[2] = isoBandEdgeLB[2] = 18;
isoBandEdgeBR[168] = isoBandEdgeLT[168] = 17;
isoBandEdgeBL[168] = isoBandEdgeLB[168] = 18;
isoBandEdgeRT[8] = isoBandEdgeBL[8] = 9;
isoBandEdgeRB[8] = isoBandEdgeBR[8] = 12;
isoBandEdgeRT[162] = isoBandEdgeBL[162] = 9;
isoBandEdgeRB[162] = isoBandEdgeBR[162] = 12;
isoBandEdgeRT[32] = isoBandEdgeTR[32] = 4;
isoBandEdgeRB[32] = isoBandEdgeTL[32] = 1;
isoBandEdgeRT[138] = isoBandEdgeTR[138] = 4;
isoBandEdgeRB[138] = isoBandEdgeTL[138] = 1;
isoBandEdgeLB[128] = isoBandEdgeTR[128] = 21;
isoBandEdgeLT[128] = isoBandEdgeTL[128] = 22;
isoBandEdgeLB[42] = isoBandEdgeTR[42] = 21;
isoBandEdgeLT[42] = isoBandEdgeTL[42] = 22;
/* rectangle cases */
isoBandEdgeRB[5] = isoBandEdgeLB[5] = 14;
isoBandEdgeRB[165] = isoBandEdgeLB[165] = 14;
isoBandEdgeBR[20] = isoBandEdgeTR[20] = 6;
isoBandEdgeBR[150] = isoBandEdgeTR[150] = 6;
isoBandEdgeRT[80] = isoBandEdgeLT[80] = 11;
isoBandEdgeRT[90] = isoBandEdgeLT[90] = 11;
isoBandEdgeBL[65] = isoBandEdgeTL[65] = 3;
isoBandEdgeBL[105] = isoBandEdgeTL[105] = 3;
isoBandEdgeRT[160] = isoBandEdgeLT[160] = 11;
isoBandEdgeRB[160] = isoBandEdgeLB[160] = 14;
isoBandEdgeRT[10] = isoBandEdgeLT[10] = 11;
isoBandEdgeRB[10] = isoBandEdgeLB[10] = 14;
isoBandEdgeBR[130] = isoBandEdgeTR[130] = 6;
isoBandEdgeBL[130] = isoBandEdgeTL[130] = 3;
isoBandEdgeBR[40] = isoBandEdgeTR[40] = 6;
isoBandEdgeBL[40] = isoBandEdgeTL[40] = 3;
/* pentagon cases */
isoBandEdgeRB[101] = isoBandEdgeTL[101] = 1;
isoBandEdgeRB[69] = isoBandEdgeTL[69] = 1;
isoBandEdgeLB[149] = isoBandEdgeTR[149] = 21;
isoBandEdgeLB[21] = isoBandEdgeTR[21] = 21;
isoBandEdgeBR[86] = isoBandEdgeLT[86] = 17;
isoBandEdgeBR[84] = isoBandEdgeLT[84] = 17;
isoBandEdgeRT[89] = isoBandEdgeBL[89] = 9;
isoBandEdgeRT[81] = isoBandEdgeBL[81] = 9;
isoBandEdgeRT[96] = isoBandEdgeTL[96] = 0;
isoBandEdgeRB[96] = isoBandEdgeLT[96] = 15;
isoBandEdgeRT[74] = isoBandEdgeTL[74] = 0;
isoBandEdgeRB[74] = isoBandEdgeLT[74] = 15;
isoBandEdgeRT[24] = isoBandEdgeBR[24] = 8;
isoBandEdgeBL[24] = isoBandEdgeTR[24] = 7;
isoBandEdgeRT[146] = isoBandEdgeBR[146] = 8;
isoBandEdgeBL[146] = isoBandEdgeTR[146] = 7;
isoBandEdgeRB[6] = isoBandEdgeLT[6] = 15;
isoBandEdgeBR[6] = isoBandEdgeLB[6] = 16;
isoBandEdgeRB[164] = isoBandEdgeLT[164] = 15;
isoBandEdgeBR[164] = isoBandEdgeLB[164] = 16;
isoBandEdgeBL[129] = isoBandEdgeTR[129] = 7;
isoBandEdgeLB[129] = isoBandEdgeTL[129] = 20;
isoBandEdgeBL[41] = isoBandEdgeTR[41] = 7;
isoBandEdgeLB[41] = isoBandEdgeTL[41] = 20;
isoBandEdgeBR[66] = isoBandEdgeTL[66] = 2;
isoBandEdgeBL[66] = isoBandEdgeLT[66] = 19;
isoBandEdgeBR[104] = isoBandEdgeTL[104] = 2;
isoBandEdgeBL[104] = isoBandEdgeLT[104] = 19;
isoBandEdgeRT[144] = isoBandEdgeLB[144] = 10;
isoBandEdgeLT[144] = isoBandEdgeTR[144] = 23;
isoBandEdgeRT[26] = isoBandEdgeLB[26] = 10;
isoBandEdgeLT[26] = isoBandEdgeTR[26] = 23;
isoBandEdgeRB[36] = isoBandEdgeTR[36] = 5;
isoBandEdgeBR[36] = isoBandEdgeTL[36] = 2;
isoBandEdgeRB[134] = isoBandEdgeTR[134] = 5;
isoBandEdgeBR[134] = isoBandEdgeTL[134] = 2;
isoBandEdgeRT[9] = isoBandEdgeLB[9] = 10;
isoBandEdgeRB[9] = isoBandEdgeBL[9] = 13;
isoBandEdgeRT[161] = isoBandEdgeLB[161] = 10;
isoBandEdgeRB[161] = isoBandEdgeBL[161] = 13;
/* hexagon cases */
isoBandEdgeRB[37] = isoBandEdgeTR[37] = 5;
isoBandEdgeLB[37] = isoBandEdgeTL[37] = 20;
isoBandEdgeRB[133] = isoBandEdgeTR[133] = 5;
isoBandEdgeLB[133] = isoBandEdgeTL[133] = 20;
isoBandEdgeBR[148] = isoBandEdgeLB[148] = 16;
isoBandEdgeLT[148] = isoBandEdgeTR[148] = 23;
isoBandEdgeBR[22] = isoBandEdgeLB[22] = 16;
isoBandEdgeLT[22] = isoBandEdgeTR[22] = 23;
isoBandEdgeRT[82] = isoBandEdgeBR[82] = 8;
isoBandEdgeBL[82] = isoBandEdgeLT[82] = 19;
isoBandEdgeRT[88] = isoBandEdgeBR[88] = 8;
isoBandEdgeBL[88] = isoBandEdgeLT[88] = 19;
isoBandEdgeRT[73] = isoBandEdgeTL[73] = 0;
isoBandEdgeRB[73] = isoBandEdgeBL[73] = 13;
isoBandEdgeRT[97] = isoBandEdgeTL[97] = 0;
isoBandEdgeRB[97] = isoBandEdgeBL[97] = 13;
isoBandEdgeRT[145] = isoBandEdgeBL[145] = 9;
isoBandEdgeLB[145] = isoBandEdgeTR[145] = 21;
isoBandEdgeRT[25] = isoBandEdgeBL[25] = 9;
isoBandEdgeLB[25] = isoBandEdgeTR[25] = 21;
isoBandEdgeRB[70] = isoBandEdgeTL[70] = 1;
isoBandEdgeBR[70] = isoBandEdgeLT[70] = 17;
isoBandEdgeRB[100] = isoBandEdgeTL[100] = 1;
isoBandEdgeBR[100] = isoBandEdgeLT[100] = 17;
/* 8-sided cases */
isoBandEdgeRT[34] = isoBandEdgeBL[34] = 9;
isoBandEdgeRB[34] = isoBandEdgeBR[34] = 12;
isoBandEdgeLB[34] = isoBandEdgeTR[34] = 21;
isoBandEdgeLT[34] = isoBandEdgeTL[34] = 22;
isoBandEdgeRT[136] = isoBandEdgeTR[136] = 4;
isoBandEdgeRB[136] = isoBandEdgeTL[136] = 1;
isoBandEdgeBR[136] = isoBandEdgeLT[136] = 17;
isoBandEdgeBL[136] = isoBandEdgeLB[136] = 18;
isoBandEdgeRT[35] = isoBandEdgeTR[35] = 4;
isoBandEdgeRB[35] = isoBandEdgeBR[35] = 12;
isoBandEdgeBL[35] = isoBandEdgeLB[35] = 18;
isoBandEdgeLT[35] = isoBandEdgeTL[35] = 22;
/* 6-sided cases */
isoBandEdgeRT[153] = isoBandEdgeTR[153] = 4;
isoBandEdgeBL[153] = isoBandEdgeLB[153] = 18;
isoBandEdgeRB[102] = isoBandEdgeBR[102] = 12;
isoBandEdgeLT[102] = isoBandEdgeTL[102] = 22;
isoBandEdgeRT[155] = isoBandEdgeBL[155] = 9;
isoBandEdgeLB[155] = isoBandEdgeTR[155] = 23;
isoBandEdgeRB[103] = isoBandEdgeTL[103] = 1;
isoBandEdgeBR[103] = isoBandEdgeLT[103] = 17;
/* 7-sided cases */
isoBandEdgeRT[152] = isoBandEdgeTR[152] = 4;
isoBandEdgeBR[152] = isoBandEdgeLT[152] = 17;
isoBandEdgeBL[152] = isoBandEdgeLB[152] = 18;
isoBandEdgeRT[156] = isoBandEdgeBR[156] = 8;
isoBandEdgeBL[156] = isoBandEdgeLB[156] = 18;
isoBandEdgeLT[156] = isoBandEdgeTR[156] = 23;
isoBandEdgeRT[137] = isoBandEdgeTR[137] = 4;
isoBandEdgeRB[137] = isoBandEdgeTL[137] = 1;
isoBandEdgeBL[137] = isoBandEdgeLB[137] = 18;
isoBandEdgeRT[139] = isoBandEdgeTR[139] = 4;
isoBandEdgeRB[139] = isoBandEdgeBL[139] = 13;
isoBandEdgeLB[139] = isoBandEdgeTL[139] = 20;
isoBandEdgeRT[98] = isoBandEdgeBL[98] = 9;
isoBandEdgeRB[98] = isoBandEdgeBR[98] = 12;
isoBandEdgeLT[98] = isoBandEdgeTL[98] = 22;
isoBandEdgeRT[99] = isoBandEdgeTL[99] = 0;
isoBandEdgeRB[99] = isoBandEdgeBR[99] = 12;
isoBandEdgeBL[99] = isoBandEdgeLT[99] = 19;
isoBandEdgeRB[38] = isoBandEdgeBR[38] = 12;
isoBandEdgeLB[38] = isoBandEdgeTR[38] = 21;
isoBandEdgeLT[38] = isoBandEdgeTL[38] = 22;
isoBandEdgeRB[39] = isoBandEdgeTR[39] = 5;
isoBandEdgeBR[39] = isoBandEdgeLB[39] = 16;
isoBandEdgeLT[39] = isoBandEdgeTL[39] = 22;
/*
The lookup tables for all different polygons that
may appear within a grid cell
*/
var polygon_table = [];
/* triangle cases */
polygon_table[1] = polygon_table[169] = p00; /* 2221 || 0001 */
polygon_table[4] = polygon_table[166] = p01; /* 2212 || 0010 */
polygon_table[16] = polygon_table[154] = p02; /* 2122 || 0100 */
polygon_table[64] = polygon_table[106] = p03; /* 1222 || 1000 */
/* trapezoid cases */
polygon_table[168] = polygon_table[2] = p04; /* 2220 || 0002 */
polygon_table[162] = polygon_table[8] = p05; /* 2202 || 0020 */
polygon_table[138] = polygon_table[32] = p06; /* 2022 || 0200 */
polygon_table[42] = polygon_table[128] = p07; /* 0222 || 2000 */
/* rectangle cases */
polygon_table[5] = polygon_table[165] = p08; /* 0011 || 2211 */
polygon_table[20] = polygon_table[150] = p09; /* 0110 || 2112 */
polygon_table[80] = polygon_table[90] = p10; /* 1100 || 1122 */
polygon_table[65] = polygon_table[105] = p11; /* 1001 || 1221 */
polygon_table[160] = polygon_table[10] = p12; /* 2200 || 0022 */
polygon_table[130] = polygon_table[40] = p13; /* 2002 || 0220 */
/* square case */
polygon_table[85] = p14; /* 1111 */
/* pentagon cases */
polygon_table[101] = polygon_table[69] = p15; /* 1211 || 1011 */
polygon_table[149] = polygon_table[21] = p16; /* 2111 || 0111 */
polygon_table[86] = polygon_table[84] = p17; /* 1112 || 1110 */
polygon_table[89] = polygon_table[81] = p18; /* 1121 || 1101 */
polygon_table[96] = polygon_table[74] = p19; /* 1200 || 1022 */
polygon_table[24] = polygon_table[146] = p20; /* 0120 || 2102 */
polygon_table[6] = polygon_table[164] = p21; /* 0012 || 2210 */
polygon_table[129] = polygon_table[41] = p22; /* 2001 || 0221 */
polygon_table[66] = polygon_table[104] = p23; /* 1002 || 1220 */
polygon_table[144] = polygon_table[26] = p24; /* 2100 || 0122 */
polygon_table[36] = polygon_table[134] = p25; /* 0210 || 2012 */
polygon_table[9] = polygon_table[161] = p26; /* 0021 || 2201 */
/* hexagon cases */
polygon_table[37] = polygon_table[133] = p27; /* 0211 || 2011 */
polygon_table[148] = polygon_table[22] = p28; /* 2110 || 0112 */
polygon_table[82] = polygon_table[88] = p29; /* 1102 || 1120 */
polygon_table[73] = polygon_table[97] = p30; /* 1021 || 1201 */
polygon_table[145] = polygon_table[25] = p31; /* 2101 || 0121 */
polygon_table[70] = polygon_table[100] = p32; /* 1012 || 1210 */
/* 8-sided cases */
polygon_table[34] = function(c){ return [ p07(c), p05(c) ];}; /* 0202 || 2020 with flipped == 0 */
polygon_table[35] = p33; /* flipped == 1 state for 0202 and 2020 */
polygon_table[136] = function(c){ return [ p06(c), p04(c) ];}; /* 2020 || 0202 with flipped == 0 */
/* 6-sided cases */
polygon_table[153] = function(c){ return [ p02(c), p00(c) ];}; /* 0101 with flipped == 0 || 2121 with flipped == 2 */
polygon_table[102] = function(c){ return [ p01(c), p03(c) ];}; /* 1010 with flipped == 0 || 1212 with flipped == 2 */
polygon_table[155] = p34; /* 0101 with flipped == 1 || 2121 with flipped == 1 */
polygon_table[103] = p35; /* 1010 with flipped == 1 || 1212 with flipped == 1 */
/* 7-sided cases */
polygon_table[152] = function(c){ return [ p02(c), p04(c) ];}; /* 2120 with flipped == 2 || 0102 with flipped == 0 */
polygon_table[156] = p36; /* 2120 with flipped == 1 || 0102 with flipped == 1 */
polygon_table[137] = function(c){ return [ p06(c), p00(c) ];}; /* 2021 with flipped == 2 || 0201 with flipped == 0 */
polygon_table[139] = p37; /* 2021 with flipped == 1 || 0201 with flipped == 1 */
polygon_table[98] = function(c){ return [ p05(c), p03(c) ];}; /* 1202 with flipped == 2 || 1020 with flipped == 0 */
polygon_table[99] = p38; /* 1202 with flipped == 1 || 1020 with flipped == 1 */
polygon_table[38] = function(c){ return [ p01(c), p07(c) ];}; /* 0212 with flipped == 2 || 2010 with flipped == 0 */
polygon_table[39] = p39; /* 0212 with flipped == 1 || 2010 with flipped == 1 */
/*
The helper functions for the above polygon_table
*/
/* triangle cases */
var p00 = function(cell){ return [[cell.bottomleft,0], [0,0], [0,cell.leftbottom]];};
var p01 = function(cell){ return [[1,cell.rightbottom],[1,0],[cell.bottomright, 0]];};
var p02 = function(cell){ return [[cell.topright, 1],[1,1],[1, cell.righttop]];};
var p03 = function(cell){ return [[0, cell.lefttop],[0,1],[cell.topleft,1]];};
/* trapezoid cases */
var p04 = function(cell){ return [[cell.bottomright,0],[cell.bottomleft,0],[0, cell.leftbottom],[0,cell.lefttop]];};
var p05 = function(cell){ return [[cell.bottomright,0],[cell.bottomleft,0],[1,cell.righttop],[1,cell.rightbottom]];};
var p06 = function(cell){ return [[1, cell.righttop],[1,cell.rightbottom],[cell.topleft,1],[cell.topright,1]];};
var p07 = function(cell){ return [[0,cell.leftbottom],[0,cell.lefttop],[cell.topleft,1],[cell.topright,1]];};
/* rectangle cases */
var p08 = function(cell){ return [[0,0],[0,cell.leftbottom],[1,cell.rightbottom],[1,0]];};
var p09 = function(cell){ return [[1,0],[cell.bottomright,0],[cell.topright,1],[1,1]];};
var p10 = function(cell){ return [[1,1],[1,cell.righttop],[0,cell.lefttop],[0,1]];};
var p11 = function(cell){ return [[cell.bottomleft,0],[0,0],[0,1],[cell.topleft,1]];};
var p12 = function(cell){ return [[1,cell.righttop],[1,cell.rightbottom],[0,cell.leftbottom],[0,cell.lefttop]];};
var p13 = function(cell){ return [[cell.topleft, 1],[cell.topright,1],[cell.bottomright,0],[cell.bottomleft,0]];};
/* square case */
var p14 = function(cell){ return [[0,0], [0,1], [1,1], [1,0]];};
/* pentagon cases */
var p15 = function(cell){ return [[1,cell.rightbottom],[1,0],[0,0],[0,1],[cell.topleft,1]];}; /* 1211 || 1011 */
var p16 = function(cell){ return [[cell.topright,1],[1,1],[1,0],[0,0],[0,cell.leftbottom]];}; /* 2111 || 0111 */
var p17 = function(cell){ return [[1,0],[cell.bottomright,0],[0,cell.lefttop],[0,1],[1,1]];}; /* 1112 || 1110 */
var p18 = function(cell){ return [[1,1],[1,cell.righttop],[cell.bottomleft,0],[0,0],[0,1]];}; /* 1121 || 1101 */
var p19 = function(cell){ return [[1,cell.righttop],[1,cell.rightbottom],[0,cell.lefttop],[0,1],[cell.topleft,1]];}; /* 1200 || 1022 */
var p20 = function(cell){ return [[1,1],[1,cell.righttop],[cell.bottomright,0],[cell.bottomleft,0],[cell.topright,1]];}; /* 0120 || 2102 */
var p21 = function(cell){ return [[1,cell.rightbottom],[1,0],[cell.bottomright,0],[0,cell.leftbottom],[0,cell.lefttop]];}; /* 0012 || 2210 */
var p22 = function(cell){ return [[cell.topright,1],[cell.bottomleft,0],[0,0],[0,cell.leftbottom],[cell.topleft,1]];}; /* 2001 || 0221 */
var p23 = function(cell){ return [[cell.bottomright,0],[cell.bottomleft,0],[0,cell.lefttop],[0,1],[cell.topleft,1]];}; /* 1002 || 1220 */
var p24 = function(cell){ return [[1,1],[1,cell.righttop],[0,cell.leftbottom],[0,cell.lefttop],[cell.topright,1]];}; /* 2100 || 0122 */
var p25 = function(cell){ return [[1,cell.rightbottom],[1,0],[cell.bottomright,0],[cell.topleft,1],[cell.topright,1]];}; /* 0210 || 2012 */
var p26 = function(cell){ return [[1,cell.righttop],[1,cell.rightbottom],[cell.bottomleft,0],[0,0],[0,cell.leftbottom]];}; /* 0021 || 2201 */
/*hexagon cases */
var p27 = function(cell){ return [[1,cell.rightbottom],[1,0],[0,0],[0,cell.leftbottom],[cell.topleft,1],[cell.topright,1]];}; /* 0211 || 2011 */
var p28 = function(cell){ return [[1,1],[1,0],[cell.bottomright,0],[0,cell.leftbottom],[0, cell.lefttop],[cell.topright, 1]];}; /* 2110 || 0112 */
var p29 = function(cell){ return [[1,1],[1,cell.righttop],[cell.bottomright,0],[cell.bottomleft,0],[0,cell.lefttop],[0,1]];}; /* 1102 || 1120 */
var p30 = function(cell){ return [[1,cell.righttop],[1,cell.rightbottom],[cell.bottomleft,0],[0,0],[0,1],[cell.topleft,1]];}; /* 1021 || 1201 */
var p31 = function(cell){ return [[1,1],[1,cell.righttop],[cell.bottomleft, 0],[0,0],[0,cell.leftbottom],[cell.topright,1]];}; /* 2101 || 0121 */
var p32 = function(cell){ return [[1,cell.rightbottom],[1,0],[cell.bottomright,0],[0,cell.lefttop],[0,1],[cell.topleft,1]];}; /* 1012 || 1210 */
/* 8-sided cases */
var p33 = function(cell){ return [[1,cell.righttop],[1,cell.rightbottom],[cell.bottomright,0],[cell.bottomleft,0],[0,cell.leftbottom],[0,cell.lefttop],[cell.topleft,1],[cell.topright,1]];}; /* flipped == 1 state for 0202 and 2020 */
/* 6-sided cases */
var p34 = function(cell){ return [[1,1],[1,cell.righttop],[cell.bottomleft,0],[0,0],[0,cell.leftbottom],[cell.topright,1]];}; /* 0101 with flipped == 1 || 2121 with flipped == 1 */
var p35 = function(cell){ return [[1,cell.rightbottom],[1,0],[cell.bottomright,0],[0,cell.lefttop],[0,1],[cell.topleft,1]];}; /* 1010 with flipped == 1 || 1212 with flipped == 1 */
/* 7-sided cases */
var p36 = function(cell){ return [[1,1],[1,cell.righttop],[cell.bottomright,0],[cell.bottomleft,0],[0,cell.leftbottom],[0,cell.lefttop],[cell.topright,1]];}; /* 2120 with flipped == 1 || 0102 with flipped == 1 */
var p37 = function(cell){ return [[1,cell.righttop],[1,cell.rightbottom],[cell.bottomleft,0],[0,0],[0,cell.leftbottom],[cell.topleft,1],[cell.topright,1]];}; /* 2021 with flipped == 1 || 0201 with flipped == 1 */
var p38 = function(cell){ return [[1,cell.righttop],[1,cell.rightbottom],[cell.bottomright,0],[cell.bottomleft,0],[0,cell.lefttop],[0,1],[cell.topleft,1]];}; /* 1202 with flipped == 1 || 1020 with flipped == 1 */
var p39 = function(cell){ return [[1,cell.rightbottom],[1,0],[cell.bottomright,0],[0,cell.leftbottom],[0,cell.lefttop],[cell.topleft,1],[cell.topright,1]];}; /* 0212 with flipped == 1 || 2010 with flipped == 1 */
/*
####################################
Some small helper functions
####################################
*/
/* assume that x1 == 1 && x0 == 0 */
function interpolateX(y, y0, y1){
return (y - y0) / (y1 - y0);
}
/*
####################################
Below is the actual Marching Squares implementation
####################################
*/
var computeBandGrid = function(data, minV, bandwidth){
var rows = data.length - 1;
var cols = data[0].length - 1;
var BandGrid = { rows: rows, cols: cols, cells: [] };
var maxV = minV + Math.abs(bandwidth);
for(var j = 0; j < rows; ++j){
BandGrid.cells[j] = [];
for(var i = 0; i < cols; ++i){
/* compose the 4-trit corner representation */
var cval = 0;
var tl = data[j+1][i];
var tr = data[j+1][i+1];
var br = data[j][i+1];
var bl = data[j][i];
if(isNaN(tl) || isNaN(tr) || isNaN(br) || isNaN(bl)){
continue;
}
cval |= (tl < minV) ? 0 : (tl > maxV) ? 128 : 64;
cval |= (tr < minV) ? 0 : (tr > maxV) ? 32 : 16;
cval |= (br < minV) ? 0 : (br > maxV) ? 8 : 4;
cval |= (bl < minV) ? 0 : (bl > maxV) ? 2 : 1;
var cval_real = +cval;
/* resolve ambiguity via averaging */
var flipped = 0;
if( (cval == 17) /* 0101 */
|| (cval == 18) /* 0102 */
|| (cval == 33) /* 0201 */
|| (cval == 34) /* 0202 */
|| (cval == 38) /* 0212 */
|| (cval == 68) /* 1010 */
|| (cval == 72) /* 1020 */
|| (cval == 98) /* 1202 */
|| (cval == 102) /* 1212 */
|| (cval == 132) /* 2010 */
|| (cval == 136) /* 2020 */
|| (cval == 137) /* 2021 */
|| (cval == 152) /* 2120 */
|| (cval == 153) /* 2121 */
){
var average = (tl + tr + br + bl) / 4;
/* set flipped state */
flipped = (average > maxV) ? 2 : (average < minV) ? 0 :