[Proj] Concluding comments
Michael P Finn
mfinn at usgs.gov
Mon Aug 13 12:41:49 EDT 2007
This reminds me of something someone famous once said: ?That depends on
what your definition of "is" is? -- Bill Clinton
"Michael Ossipoff" <mikeo2106 at msn.com>
Sent by: proj-bounces at lists.maptools.org
08/12/2007 07:35 AM
Please respond to
"PROJ.4 and general Projections Discussions" <proj at lists.maptools.org>
proj at lists.maptools.org
[Proj] Concluding comments
This is my last posting here. I?m not continuing the argument about maps.
But I have a right to reply to some of your mis-statements and mis-quotes
me. They?ve been the constant theme of your postings, but, for brevity I?m
mostly commenting on those in your most recent posting. You should
understand that you are not asked or expected to reply to this.
Accurate directly-measured lat/long positions are a ?metric criterion? no
less than is equal-area.
Equal-area is a rigorous concept. "Giving accurate and easy
directly-measured lat/long coordinates" is not
I comment now:
First, the word ?easy? was not in ?accurate directly-measured lat/long
positions?, the phrase by which I referred to a metric criterion.
Definitions should be precise, but I didn?t say that ?accurate
directly-measured lat/long positions? was a definition. It was a brief
description referring to an obvious, and obviously precisely-definable,
property of the sinusoidal.
Yes, you could say I was out of line when I referred to a property that I
hadn?t defined, but, as I said, the property was obvious. But apparently
obvious enough, and so I spelled it out for you and walked you through it,
when I defined the linearly interpolable positions property.
Though I?ve already replied to ?Your analysis of the issues surrounding
thesis seems to evolve as we talk?, and ?You?ve now evolved to an
interrupted sinusoidal?, I want to mention those false statements again,
examples of your overall tendency toward falsity in these postings. You
that I?d ?evolved to? the sinusoidal, though I?d been suggesting it from
first posting here, for when equal-area is desired. My position has been
consistent in my postings here.
But more importantly, and back to your thesis, it's not clear to me how
often the cartographer shares your priorities.
Hello? If cartographers shared my priorities, about making data maps
genuinely usable for their stated purpose, I wouldn?t have had reason to
post my first message here. Cartographers apparently are conditioned to
minimize distortion, often to the detriment of a map?s stated purpose.
But, then, cartographers don?t share your priorities either. You said that
data maps should be equal area, but if you look at some atlases you?ll
many data maps that are not equal area. You said that data maps should
minimize the inaccuracy of directly-measured distances, but if you look at
some atlases you?ll find many data maps on projections that would
not be chosen for that purpose. Oh, and did I mention that those two
requirements of yours are mutually incompatible?
You may want to think of a map as one that fits your notion of a "data
Wrong. It?s not how I ?want to think of a map?. The maps to which I
_are_ data maps, by which I said that I mean spatial distribution maps.
They?re that whether or not someone wants to think of them as such.
, but people may be using it for many other purposes as well.
By definition, spatial distribution maps tell where certain species
temperature zones, etc., are. For those interested, they also show their
relative areas. But you?re speculating that maybe there may be many other
unspecified purposes for which people use them. Let me underscore your
?may?, and the fact that you?re talking pure unsupported speculation, and
that you don?t even specify the purposes to which you refer.
Oh yes, you did mention distance. ?Hey Joe, our seven and a half minute
topographic map fell out of my backpack somewhere. Could you toss me that
bird book, the one with the North America maps showing where the
bird-species live? We?ll use that to find our way back to the car, and to
find out how far it is.? It?s good to have a bird book or a rainfall
distribution map that shows accurate distances! :^)
What, then, is your thesis?
You added [after describing three theses, A, B, and C, and labeling thesis
as ?something else?]:
If (D), then I am completely lost, and I must apologize for not following
Then you?re completely lost, because it?s D. It?s D, because none of your
theses A, B, and C accurately quote what I?d been saying. If those
your best effort to quote what I?d been consistently saying, then you
are completely lost.
your jargon is idiosyncratic
Definition of jargon:
1. Specialized language used when specialized language isn?t needed, and
used in order to obfuscate a topic or to impress one or more listeners.
2. Specialized language used by someone against whose statements the
wants to argue.
To a large extent you probably meant that I _wasn?t_ using jargon, but was
instead using English, the kind in standard dictionaries. Saying that
someone isn?t using the right jargon serves the same purpose as saying
someone isn?t using the correct secret handshake or password. As I said, I
tried to find an ica glossary of map projection terminology.
We?ve discussed how I mis-guessed the officially correct meaning of
?equidistant?. Instead of a definition of ?equidistant?, I?d only run
definitions of three equidistant projections. Their definitions mentioned
equally-spaced parallels. So my guess was a good one, even if, unknown to
me, the official types have said that the meridians must be straight.
The projection that I called ?equidistant elliptical? has something
important in common with equidistant cylindrical and equidistant conic:
Equally spaced parallels. Equally spaced parallels are probably the most
important and useful property of an equidistant cylindrical that makes it
different from an equal-area cylindrical. And ?equidistant elliptical? has
that property in common with the officially-named equidistant projections.
With both projections, the equally spaced parallels greatly facilitate
determination of latitude. Maybe that means that it would be more useful
not limit ?equidistant? to uniform scale along straight meridians.
Maybe ?equidistant? could be meaningfully and usefully defined in terms of
equally spaced parallels, and maybe it should be. But I?m only saying that
my guess was well justified.
If, officially, equidistant maps must have straight meridians, then I have
to give the name ?equally-spaced elliptical? to the projection that I?d
previously called ?equidistant
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