5 replies to this topic

[brian314]

Hi, any idea what projection is being used in this map? Thank you.

[ez_duce]

Hi, any idea what projection is being used in this map? Thank you.

Not sure, but it looks like a lambert conformal conic.

[sitesatlas]

It looks like it's the Lambert Conformal Conic projection. I had a little time on my hands and I got a pretty close fit with a latitude of 85 (!) and longitude of -98.

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[brian314]

It looks like it's the Lambert Conformal Conic projection. I had a little time on my hands and I got a pretty close fit with a latitude of 85 (!) and longitude of -98.

Thank you so much! I really appreciate it.

[M.Denil]

" a latitude of 85 (!) "

I too think that 85° sounds a little extream for a standard parallel. There are usually two standard parallels with that projection anyway, are there not? If the US is streched out that far, then it is more likely and Albers.

It is pretty hard to tell a Lamberts conic from an Albers, without a good number of displayed parallels, especially over such a small span as the lower 48 states.

USGS standards are
Lamberts Conformal Conic with two standard parallels at 33° and 45°
Albers Equal Area Conic with two standard parallels at 29.5° and 45.5°

Mark Denil
National Ice Center

[sitesatlas]

" a latitude of 85 (!) "

I too think that 85° sounds a little extream for a standard parallel. There are usually two standard parallels with that projection anyway, are there not? If the US is streched out that far, then it is more likely and Albers.

It is pretty hard to tell a Lamberts conic from an Albers, without a good number of displayed parallels, especially over such a small span as the lower 48 states.

USGS standards are
Lamberts Conformal Conic with two standard parallels at 33° and 45°
Albers Equal Area Conic with two standard parallels at 29.5° and 45.5°

Mark Denil
National Ice Center

You could be right that it's an Albers projection instead of the LCC. I found the key to be Florida, which flares out at a sharp angle that was hard to replicate. I tried the LCC projection with two standard parallels and found that the results were so similar, it was just easier to use just one for trial-and-error purposes (it took me at least 20 iterations to get it right).

It would be interesting to see what the results would be for an Albers projection here. Anyone up to the task?