 In some cases, the "historical" sites are still collecting data but due to reporting and data processing delays (of more than a decade in some cases) they do not contribute to current temperature estimates.As is evident from this plot, the most densely instrumented portion of the globe is in the , while is the most sparsely instrumented land area.Parts of the Pacific and other oceans are more isolated from fixed temperature stations, but this is supplemented by volunteer observing ships that record temperature information during their normal travels.