Test of acreage calculation for polygons that span more than 1 UTM zone.

utm_zone_partial.js

// Zone spanning polygon
{
  "type": "MultiPolygon",
  "coordinates": [
    [
      [
        [-90.00575, 35.99485],
        [-89.99339, 35.99485],
        [-89.99339, 36.00481],
        [-90.00575, 36.00481],
        [-90.00575, 35.99485]
      ]
    ]
  ]
}

// Using Zone 15 projection
// => 304.64208165875334 acres
// Using Zone 16 projection
// => 304.64176688085104 acres

// Calculations with Polygons split so each is contained by the UTM zone.

// Zone 15

{
  "type": "MultiPolygon",
  "coordinates": [
    [
      [
        [-90.00575, 35.99485],
        [-90.0, 35.99485],
        [-90.0, 36.00481],
        [-90.00575, 36.00481],
        [-90.00575, 35.99485]
      ]
    ]
  ]
}

// => 141.7220884545912 acres

// Zone 16

{
  "type": "MultiPolygon",
  "coordinates": [
    [
      [
        [-89.999999999, 35.99485],
        [-89.99339, 35.99485],
        [-89.99339, 36.00481],
        [-89.999999999, 36.00481],
        [-89.999999999, 35.99485]
      ]
    ]
  ]
}

// => 162.9186747197805 acres

// Partials Combined
// => 304.6407631743717 acres

// Original Non-Split polygon Zone 15
// => 304.64208165875334 acres

// Original Non-Split polygon Zone 16
// => 304.64176688085104 acres