{
  "id": "UN1028",
  "name": "chain (U.S. survey foot)",
  "ml_name": "ip_ch_{US}",
  "symbol": "ch",
  "reference": "https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8#C"
}