Johannes Janssonius's chart of the Pacific Ocean was the first included in a Dutch atlas, his 'Atlas Novus' of 1650. It includes some interesting myths: a chain of islands across the centre of the map, a remnant of Gerard Mercator's concept of "Terra Australis"; a large landmass labeled "Terra Incognita" along the top; and California is an island. The coastline of Australia extends to only the discoveries of Willem Janszoon's voyage in the 'Duyfken' (1606) down the south coast of New Guinea and along the west coast of the Cape York peninsula, adding the discoveries of Jan Carstensz in command of the 'Pera' during his voyage of 1623, which followed the route of the 'Duyfken', and continued into the Gulf of Carpentaria.

The mapmaker
The son of an established printer — publisher Jan Jansz., Johannes Janssonius (1588-1664), was Willem Jansz. Blaeu's main rival. In 1618, he set up his own cartographic publishing firm on the Damrak, the central canal and commercial hub of Amsterdam. In 1612, he married Elisabeth de Hondt, the daughter of Jodocus Hondius,… another of Blaeu's competitors. "Theirs was a rivalry which soon grew to include accusations of plagiarism and theft of intellectual property, a state of affairs not helped by Blaeu's use of the name "Jan Zoon" to sign his works" (Woods).

Although Janssonius's first independent work was an edition of Blaeu's 'Licht der Zeervaert' in 1620, he is first associated with the Mercator-Hondius atlas in 1633, when the French edition includes his name on the title-page. The Dutch editions of 1634, 1638 and 1647 were published by Janssonius alone; but the English edition, 1636, the Latin of 1638, were issued by both Janssonius and Hondius. After 1638 the name of the atlas changed to 'Atlas Novus…', and from 1649 Hondius's name no longer appears on the title-page or preface. In time, Janssonius would add a fifth volume, the 'Atlas Maritimus' (1657), a significant sea-atlas; and eventually, a further five volumes including maps from every corner of the globe, by about one hundred credited authors and engravers. The final, eleventh volume, Andreas Cellarius's celestial atlas, completed the 'Atlas Major' in 1660.