cfrye-esristaff

Map Projections:

Blog Post created by cfrye-esristaff Employee on Jul 24, 2018

Today, a colleague asked me: "Do we have any base maps in ArcGIS Online that are close to the Hobo-Dyer projection, below? Or something similar that is equal area?"  Here was my response:

 

We have both Cylindrical Equal Area and Behrmann, so why would I use this one (the wiki does not give me a compelling reason)?

 

I make this point because there are better options for cartographic visualization (Mollweide and even Goode’s).  For Analysis, Cylindrical Equal Area is very good, except in extreme polar regions. However, the Add Geometry Attributes tool fully compensates for analysis by calculating geodesic area. I’ve done a comparison on a half degree fishnet and only found the only differences were in the two uppermost and lowermost latitude rows, and most of them were very close. If I were analyzing a polar area, I’d be using a Stereographic projection for visualization with that geodesic area option for analysis.

 

In general, I think a lot of the ‘ad nauseam’ projected coordinate systems were responses to lack of coordinate precision (pre-32 bit databases), and relatively slow computing technology. Today, my suspicion is we could get away with as few as twenty projected coordinate systems (the rest would generally fall under artistic license).

 

I would add that for analysis, equidistant projected coordinate systems are also vital for spatial analysis; and Equidistant Cylindrical is my preferred option.

 

For context, I have spent a good deal of my time in recent years working on global datasets, needing to deal with relative large areas and great distances, rather than regional or small study area geographic extents, where there are other proven options (national grids or state plane).

 

Cheers!

 

Charlie

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