A similar feature is found at 13 degrees north between 230 degrees and 250 degrees longitude.

在北纬13度、经度230度到250度之间也发现了类似的特征。

He noted the latitude and longitude, then made a mark on the admiralty chart.

他记下经度和纬度，然后在海图上作了标记。

Determining longitude exactly was a problem of vital importance for the safety of commercial shipping.

经度的精确确定对商业船运的安全关系重大。