{
  "id": "tle-parsing",
  "title": "Two-line element parsing",
  "summary": "From raw text to a structured element set: line classification, checksum verification, field extraction, and the cross checks.",
  "nodes": [
    {
      "id": "text",
      "label": "Input text",
      "kind": "data",
      "group": "input",
      "summary": "One, two, or three lines; blank lines are ignored and any of the common line endings is accepted.",
      "label_zh": "输入文本",
      "summary_zh": "一行、两行或三行；忽略空行，接受各种常见换行符。"
    },
    {
      "id": "split",
      "label": "Split and classify lines",
      "kind": "step",
      "group": "parse",
      "summary": "A leading line that does not begin with '1 ' is the satellite name; the next two lines are the data lines.",
      "label_zh": "切分并分类各行",
      "summary_zh": "不以 \"1 \" 开头的首行是卫星名称；其后两行是数据行。"
    },
    {
      "id": "count",
      "label": "Two data lines?",
      "kind": "decision",
      "group": "parse",
      "summary": "The format requires exactly two data lines.",
      "label_zh": "有两行数据？",
      "summary_zh": "格式要求恰好两行数据。"
    },
    {
      "id": "too_few",
      "label": "TooShort",
      "kind": "terminal",
      "group": "error",
      "summary": "Fewer than two data lines were present.",
      "summary_zh": "数据行少于两行。"
    },
    {
      "id": "checksum1",
      "label": "Verify line 1 checksum",
      "kind": "step",
      "group": "verify",
      "summary": "Sum the digits and the minus signs of the first 68 columns modulo ten and compare with column 69.",
      "api": "verify_line_checksum",
      "label_zh": "校验第 1 行",
      "summary_zh": "对前 68 列的十进制数字与负号求和后对十取模，与第 69 列比较。"
    },
    {
      "id": "checksum_ok",
      "label": "Checksums match?",
      "kind": "decision",
      "group": "verify",
      "summary": "Each line is verified independently, so a corrupted line is reported with its number.",
      "label_zh": "校验和一致？",
      "summary_zh": "每行独立校验，因此损坏的行会连同行号一起报告。"
    },
    {
      "id": "checksum_fail",
      "label": "Checksum error",
      "kind": "terminal",
      "group": "error",
      "summary": "A line checksum does not match its contents.",
      "api": "ElementErrorKind",
      "label_zh": "校验和错误",
      "summary_zh": "某行校验和与其内容不一致。"
    },
    {
      "id": "fields1",
      "label": "Read line 1 fields",
      "kind": "step",
      "group": "fields",
      "summary": "Catalog number, classification, designator, epoch, the two derivatives, BSTAR, and the element set number.",
      "label_zh": "读取第 1 行字段",
      "summary_zh": "编目号、密级、国际编号、历元、两个导数、BSTAR 与元素集编号。"
    },
    {
      "id": "fields2",
      "label": "Read line 2 fields",
      "kind": "step",
      "group": "fields",
      "summary": "Inclination, right ascension, eccentricity, argument of perigee, mean anomaly, mean motion, and the revolution number.",
      "label_zh": "读取第 2 行字段",
      "summary_zh": "倾角、赤经、偏心率、近地点幅角、平近点角、平均运动与圈数。"
    },
    {
      "id": "exponent",
      "label": "Decode exponent fields",
      "kind": "step",
      "group": "fields",
      "summary": "A sign, a mantissa with an assumed decimal point, an exponent sign, and one exponent digit.",
      "api": "ElementErrorKind",
      "label_zh": "解码指数字段",
      "summary_zh": "尾数符号、带隐含小数点的尾数、指数符号与一位指数数字。"
    },
    {
      "id": "epoch",
      "label": "Expand the two digit year",
      "kind": "step",
      "group": "fields",
      "summary": "Years 57 through 99 are in the twentieth century and 00 through 56 in the twenty-first.",
      "api": "Epoch",
      "label_zh": "展开两位年",
      "summary_zh": "57 至 99 属于二十世纪，00 至 56 属于二十一世纪。"
    },
    {
      "id": "match",
      "label": "Catalog numbers match?",
      "kind": "decision",
      "group": "crosscheck",
      "summary": "The two lines must describe the same object.",
      "label_zh": "编目号一致？",
      "summary_zh": "两行必须描述同一目标。"
    },
    {
      "id": "mismatch",
      "label": "MismatchedElementSet",
      "kind": "terminal",
      "group": "error",
      "summary": "The two lines carry different element set numbers.",
      "api": "ElementErrorKind",
      "summary_zh": "两行携带不同的元素集编号。"
    },
    {
      "id": "element",
      "label": "TwoLineElement",
      "kind": "terminal",
      "group": "output",
      "summary": "The structured element set, with the units of the format preserved.",
      "api": "TwoLineElement",
      "summary_zh": "结构化元素集，保留格式所用的单位。"
    }
  ],
  "edges": [
    {
      "source": "text",
      "target": "split",
      "kind": "flow",
      "label": null
    },
    {
      "source": "split",
      "target": "count",
      "kind": "flow",
      "label": null
    },
    {
      "source": "count",
      "target": "too_few",
      "kind": "branch",
      "label": "no"
    },
    {
      "source": "count",
      "target": "checksum1",
      "kind": "branch",
      "label": "yes"
    },
    {
      "source": "checksum1",
      "target": "checksum_ok",
      "kind": "flow",
      "label": null
    },
    {
      "source": "checksum_ok",
      "target": "checksum_fail",
      "kind": "branch",
      "label": "no"
    },
    {
      "source": "checksum_ok",
      "target": "fields1",
      "kind": "branch",
      "label": "yes"
    },
    {
      "source": "fields1",
      "target": "fields2",
      "kind": "flow",
      "label": null
    },
    {
      "source": "fields2",
      "target": "exponent",
      "kind": "flow",
      "label": null
    },
    {
      "source": "exponent",
      "target": "epoch",
      "kind": "flow",
      "label": null
    },
    {
      "source": "epoch",
      "target": "match",
      "kind": "flow",
      "label": null
    },
    {
      "source": "match",
      "target": "mismatch",
      "kind": "branch",
      "label": "no"
    },
    {
      "source": "match",
      "target": "element",
      "kind": "branch",
      "label": "yes"
    }
  ],
  "title_zh": "两行元素解析",
  "summary_zh": "从原始文本到结构化元素集：行分类、校验和验证、字段提取与交叉检查。"
}