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Saturday, December 5, 2015

GeoReferencing a 1766 Red Hook and Downtown Brooklyn Map

Hi Folks:

  I came across an interesting web site that deals with some of the material found here but in a more historical fashion.  It is called Ephemeral New York

I came across an interesting map from that site.  I was not able to get the source but it seems to be an early map of the City of Brooklyn in 1766-7.   At that time, what is now the borough of Brooklyn, consisted of a number of small towns, some dating back to early Dutch settlement.  Then, the town of Brooklyn was around the area nearest Manhattan (New York) and consisted of the area of present day downtown Brooklyn and Red Hook.  The map was truncated so I could not get the names of the owners in the legend.

  This is the map posted in Ephemeral New York.  There does not appear to be many streets except the "Road to Flatbush" and the "Road to Jamaica", which were towns further to the east on Long Island.  The road to Flatbush probably became Flatbush Avenue and the other road to Jamaica may have become "Fulton Street".  These road split as shown on the map and will become an important point to georeference using ARCGIS.  It is interesting to note that on this map, surveyed in the years 1766 and 1767, elevation was taken into account on what appears to be hills.  On this map, the hills appear to be brown and have a contour appearance, like a modern contour map.

Using Adobe, I transfered the above map from a xxx file into a TIFF file, which is a raster file in ARCGIS.  Using  a modern street grid of Brooklyn ( from Bytes of the Big Apple), I started the georeferencing process.  Notice from the old map the the coast line is not the same as we have today.  Apparently, there have been much landfill in the past 250 years.  Acting very fast, I did no research on the points listed on the map to get a more accurate overlay, but I did use one point on the old map where the road to Flatbush splits off from the road to Jamaica.  This is the Flatbush Fulton Street intersection.  The modern streets today may not be in the exact location shown on the map 250 years ago.  I also picked a point near Wallabout Bay and crossed referenced it on a modern map since the shape of the coastline appears the same.  I also picked an arbitrary point on Governours Island as well.

  Notice how the resultant georefeneced map is distorted.  In the base ARCGIS map, I  brought in the modern subway system and stop file and the street grid.  The results are not perfect but shows on the 1766 map where the modern street grid may fall, perhaps.
   I noticed that the "hill" areas on the 1766 map appear somewhat accurate.  One way to test this is to bring in a modern contour map and see if the concentration of contour lines really correspond to a hill on the 1766 map.

  In this frame  above, the hilly areas are show by a concentration of dark lines.  It is hard to see the original hill drawings on the 1766 map so I lightened the contour lines by changing the display percentage.

Generally the increase in slope shown by the contour lines on the modern map corresponds to the hilly areas shown on the 1766 map, even after 250 years of development on the surface.

Although not shown on the subway map above, but the street elevation at Bergen and Smith Streets is 24 feet ( this will need to be verified ).  This station may have had a water condition that resulted in the closing of the lower level (Express) platforms.  This area may have been adjacent to the Gowanas Canal but the elevation is high.  This will be discussed later.  Thanks folks: Tramway null (0).

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