In 1764 Blaskowitz was assigned by Samuel Holland to chart the coast of Rhode Island, no doubt to ascertain the suitability of the area of Newport as a harbor for ships of the British Navy.  In the course of this work he also accepted a private commission by the local Rhode Island farmers in around 1770 to create a map for their purposes.  It is a particularly charming feature of this map that the names of the principle farmers have been added by Blaskowitz, apparently in his own hand as if as a note to himself or perhaps as an afterthought. Note the inclusion of the Fourth Baptist Meeting House ('G' on the index) which was founded in 1770.

It is likely that he used the same geographic information as the basis for both the private commission and the military work.  Engineers, surveyors and cartographers of the time, such as Charles Blaskowitz, were poorly rewarded by the government for their skills, so private commissions probably provided welcome additional income.  Blaskowitz therefore was able to redraw and adapt the map with the positions of the defensive batteries for use by the British. 

Undoubtedly, along with the 1770 Plan of Rhode Island with the adjacent islands and coast of Narragansett Bay (see Heritage Chart A105), this chart was a forerunner to the well-known Blaskowitz map of 1777 which was published by Faden - note that the names appear in the same order on the later map of 1777. 

The inset Plan of the Town of Newport on the left-hand side of the chart is clearly used as the basis for later publications of the Plan of the Town of Newport by both Blaskowitz (privately published by Faden in 1777), and by Des Barres in The Atlantic Neptune folio in 1777 (see Heritage Chart A103a).  Close inspection of the inset reveals an intended extension of the town plan to the South (note the orientation of the town plan with North to the left).  It is the same as the Des Barres charts (see Heritage Charts A103a and A103b).