# 格奥德¶

## 简介¶

geod +ellps=<ellipse> [-afFIlptwW [args]] [+opt[=arg] ...] file ...

invgeod +ellps=<ellipse> [-afFIlptwW [args]] [+opt[=arg] ...] file ...

## 描述¶

geod （直接）和 invgeod （逆）执行测地（大圆）计算，以确定给定初始点纬度、经度、方位角和距离（直）或初始点和终点纬度和经度之间的前后方位角和距离（逆）的终点的纬度、经度和后方位角。结果精确到四舍五入 $$|f| < 1/50$$ 在哪里 $$f$$ 正在变平。

invgeod 可能并非在所有平台上都可用；在这种情况下，请使用 geod -I 相反。

-I

-a

-t<a>

Where a specifies a character employed as the first character to denote a control line to be passed through without processing.

-le

-lu

-f <format>

Where format is a printf format string to control the output form of the geographic coordinate values. The default mode is DMS for geographic coordinates and "%.3f" for distance.

-F <format>

Where format is a printf format string to control the output form of the distance value (-F). The default mode is DMS for geographic coordinates and "%.3f" for distance.

-w<n>

Where n is the number of significant fractional digits to employ for seconds output (when the option is not specified, -w3 is assumed).

-W<n>

Where n is the number of significant fractional digits to employ for seconds output. When -W is employed the fields will be constant width with leading zeroes.

-p

geod 也可用于沿两点之间的测地线或沿距地理点指定距离的弧确定中间点。在这两种情况下，必须用 +lat_1=lat+lon_1=lon 参数和终点 +lat_2=lat+lon_2=lon 或从初始点到 +S=distance+A=azimuth 必须指定。

## 实例¶

geod +ellps=clrk66 <<EOF -I +units=us-mi
42d15'N 71d07'W 45d31'N 123d41'W
EOF


-66d31'50.141" 75d39'13.083" 2587.504


geod +ellps=clrk66 <<EOF +units=us-mi
42d15'N 71d07'W -66d31'50.141" 2587.504
EOF


45d31'0.003"N 123d40'59.985"W 75d39'13.094"


## 进一步阅读¶

1. GeographicLib <https://geographiclib.sourceforge.io> _.

2. C、 F.F.卡尼， Algorithms for Geodesics 《大地测量学杂志》 87 (1), 43–55 (2013); addenda .

3. A geodesic bibliography <https://geographiclib.sourceforge.io/geodesic-papers/biblio.html> _.