I have come across in my textbook ,that the longitudinal extent of Asia is about 25 degree East to 170 degree East. However , looking at the map of Asia , I think that it should be 170 degree West . I googled this several times but some said it's East and some said West.
Please tell the correct one.
The map surface of mainland Asia is entirely contained within a Geodetic quadrangle formed from segments of latitude going through its north and south extremes and segments of longitude passing through the east and west extremes. Cape Chelyuskin is at 77° 43′ N; Cape Piai in the Malay Peninsula is at 1° 16′ N; Cape Baba in Turkey is at 26° 4′ E; Cape Dezhnyov is at 169° 40′ W; that is, mainland Asia ranges through about 77° of latitude and 195° of longitude,[5] distances of about 8,560 km (5,320 mi) long by 9,600 km (6,000 mi) wide according to Chambers, or 8,700 km (5,400 mi) long by 9,700 km (6,000 mi) wide according to Pearson's.
Source:wikipedia
To add some visual clarification:
Asia crosses the 180 degree meridian east. So it is about 170 west, equivalent to 190 degrees east from the prime meridian.
asia crosses 180 degree longitude and its eastern end touches 170 digree meridian in the western hemisphere so its extent is 25`E-170'W
The Google Map you see is an actually use web mercator auxiliary sphere and that what you see is for the web or on the internet and it is not true projection. That is why you have @SIslam's comments is corrected.
You can read what ESRI is writing about it and why anyone who post it on the web use it.
