And although the study's geographical coverage is the most comprehensiveso far for work of this type, there are still blank areas-notably in Australia, Central Asia, South America and the northern Pacific Ocean.

而且，尽管这项研究的地理覆盖范围是迄今为止同类中最大的，它仍有空白区域--尤其指澳洲，中亚，南美和北太平洋地区。