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Seafloor Map of Hawai‘i

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#1
Tom Patterson

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I just released the Seafloor Map of Hawai‘i. If you have an interest in oceanography, like the color blue, and need an on-line break from winter weather, check it out at:

http://www.shadedrelief.com/hawaii

This is a map that I have wanted to make for some time, but which had to wait until good bathymetry data became available. As it was, I had to patch together data from two sources to complete the map coverage. The text blurbs highlighting facts about the Hawaiian seafloor—a truly mysterious place—try to make scientific aspects of the map more interesting to a general audience.

The map uses the Geographic projection, a first for me, which is not such a cartographic sin given that Hawai‘i is in the tropics. Depicting the topography with plan oblique relief is perhaps more controversial, however. I am curious to hear what you think of this technique.

#2
David Medeiros

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Tom, this is a gorgeous map! One I definitely want on my wall.

I think the plan oblique looks fantastic. This is one of the simplest, most elegant scientific maps of this type I've ever seen and at the same time it captures all of the most important or interesting scientific information about Hawaiian geology. I only have two questions/comments:

1) why is the note about Pearl Harbor so far from the feature?

2) I wonder if a more general note on the underwater landslide activity in Hawaii would be appropriate? Its obvious enough in the relief and specific notes about slides but its such a major part of Hawaii's geologic dynamism and one that was discovered relatively more recently.

I get a lot of my fascination with physical geography from having been born and raised in Hawaii, an amazing physical landscape. As a non elected, unofficial, completely self invented representative of the state, I approve this map! :D



One other question, this may be an optical illusion, but is there a gradient in each of the color classes for the depth legend? It looks as if each color band is slightly lighter on its lower edge.

GIS Reference and Instruction Specialist, Stanford Geospatial Center.

 

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#3
tonyw

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The text blurbs highlighting facts about the Hawaiian seafloor—a truly mysterious place—try to make scientific aspects of the map more interesting to a general audience.


Hi Tom,
A fascinating and well presented map. We just returned from visiting Maui and Hawaii and the information you present is very timely. Another fact to add about the depression of the seabed by the great weight of the islands is at http://hvo.wr.usgs.g...8/98_08_20.html that the seafloor is depressed by 8,000 m (26,000') making Mauna Loa about 17,170 (56,000') tall from its base!

Nice work,
-Tony

#4
Tom Patterson

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David,

Thanks much for your comments. It is nice getting approval from a kama‘aina, even one that now lives on the mainland!

1) why is the note about Pearl Harbor so far from the feature?


I was trying to avoid placing notes on the more detailed bathymetry closer to the islands, the Maui Nui note being the exception to this rule. My thinking in the case of Pearl Harbor was that most people would know to look for it on O‘ahu. So into the deep ocean it went.

2) I wonder if a more general note on the underwater landslide activity in Hawaii would be appropriate? Its obvious enough in the relief and specific notes about slides but its such a major part of Hawaii's geologic dynamism and one that was discovered relatively more recently.


Good suggestion. In fact, I have a note prepared for future map update 1.1.

3) One other question, this may be an optical illusion, but is their a gradient in each of the color classes for the depth legend? It looks as if each color band is slightly lighter on its lower edge.


Now that you mention it, I see it too. A Photoshop check, however, shows that the color chips are consistent from top to bottom.

A nastier related problem was color banding north of the Hawaiian Deep where the dark blue blends with slightly lighter blue. I worked with 16-bit data, added noise, and used the rubber stamp tool in PS to get rid of it—the usual tricks—but the problem persists. It is more noticeable when the map is saved as a jpeg.

#5
Jacques Gélinas

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Real Nice map.

Questions:
From what I saw in photoshop, the printing size is 17 x 12,5 inches at 250dpi. Is that the recommended size if I was to print this one to put on my wall? If I do print it, I will make sure the blue cartridge is full :) .

Thanks for sharing your work.

regards,

Jacques Gélinas
cartographer
www.cartesgeo.ca


#6
Tom Patterson

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Real Nice map.

Questions:
From what I saw in photoshop, the printing size is 17 x 12,5 inches at 250dpi. Is that the recommended size if I was to print this one to put on my wall? If I do print it, I will make sure the blue cartridge is full :) .

Thanks for sharing your work.

regards,


Jaques,

Yes, that is the size of the smaller Web map at 250 DPI, my working resolution. The wall map is twice that size at 250 DPI. Depending on your printer and other variables, you may need to lighten the map a little in Photoshop (I prefer Levels) to tame the blue.

HP and Epson should send me a royalty on blue cartridge sales ;) .

#7
DaveB

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3) One other question, this may be an optical illusion, but is their a gradient in each of the color classes for the depth legend? It looks as if each color band is slightly lighter on its lower edge.


Now that you mention it, I see it too. A Photoshop check, however, shows that the color chips are consistent from top to bottom.

I believe that is due to a phenomenon called Mach Banding and it's "all in your head" (so, yes, basically an optical illusion). :D

Beautiful map, Tom!
Dave Barnes
Esri
Product Engineer
Map Geek

#8
Clark Geomatics

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Tom, you continue to raise the cartographic bar forcing the rest of us to pull up our socks as we try to keep up! Beautiful map (and calming, due to the blue)! As per David M's comment about your map's scientific merit, it does show and explain very clearly the legacy of the islands and their ongoing creation due to the volcanic hotspot - the key to the future lies in the past!
Cheers,

Jeff Clark
Principal
www.clarkgeomatics.ca

#9
Gretchen Peterson

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Loved your map. I posted briefly about it here and it garnered some nice responses on twitter: http://www.gretchenp...om/blog/?p=1463.

#10
magictune

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Spectacular map. So expressive with so few colors. And special 'bravo' for those small text widgets (notes) - I'm still new in cartography and I don't dare putting them on my maps, but I sure enjoy reading them on pro maps ! :)

#11
mapfax

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Tom--Intriguing map with great graphics and annotation. I went right to Lo'ihi seamount and found out that I should not hold my breath waiting for it to break the surface. The hotspot inset, with the age of the islands, is a great graphic for my physical geography class. Thanks for making the map. It is quite creative.
David




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