Why I’ve Gotten Away from Using NYSDOT Topographic Maps
For the first year of doing topographic maps, I relied extensively on using NYSDOT topographic maps, I originally downloaded from the NYSGIS consortium website. The NYSDOT topographic maps have a lot of good information on them, an in many ways have the most accurate topography.
But what I’ve also found with those maps is they have several real limitations…
1) They Don’t Scale Well.
NYSDOT topographic maps are designed to viewed at 1:2400 feet ratio, as they are 7.5″ quads. You can get away with rendering them anywhere between 1:1800 to 1:2600, but beyond that the text looks too small, too crowded, or two pixelated. For smaller parks and larger areas, NYSDOT topographic maps do not work well.
2) Unneeded Information and Clutter.
DOT Topographic Maps try to suit the need of any user, and include information like town lines and other jurisdictional information that is unnecessarily for the average outdoors person.
3) Outdated Information.
Often topographic maps have dated information on man-made boundaries and buildings. The state often buys new land, demolishes existing buildings, and closes off trails. Old trails appear on topographic maps, as do labels such a “Restricted”, even though to this day such roads may be valid, despite the incorrect or outdated information on topographic maps.
4) Metric Scale; Differentiating Contour Scales.
Metric elevations are maddening for anyone trying to calculate their elevation from select DOT topo maps, and often when you load multiple topographic maps, they do not fit together seamlessly, as one will be using one unit for contours, while another will use another unit. Contour scales throughout the state very widely, which when put together can be confusing.
On the other hand, topos do have some benefits…
1) Most Accurate Shorelines.
The Census Water Area and Liner Water Shapefiles from TIGER/Line are pretty accurate, but they are not nearly as good as topographic maps.
2) Wetlands.
Currently I don’t have any good source of data or wetlands to add to my maps. I probably should do more research into this, as I know the state does have wetland maps available — but how much of a PITA are they to use?
3) Buildings.
Topographic maps have many of the buildings on them. While this information can be outdated, it does provide useful information to the viewer of such maps. TIGER/line has some features, like cemeteries and some buildings, but this data set is tiny compared to what’s on the NYSDOT topographic maps.