[Proj] A much better summary of a discussion on this list

Thu Aug 16 07:08:42 EDT 2007

Again, I’m sorry to post so much, but I haven’t properly commented on the 
bizarre events of the discussion with Daan.

Before you get angry at me for posting this long message of comments on 
Daan’s statements, I want to remind you that, for each of these comments, 
there was a posted statement by Daan. I’m replying to a huge volume of 
attack based on mis-statements, mis-quotes, straw-man tactics, etc. That’s 
why this posting is so long.

I didn’t start writing to Daan. Daan started writing to me. I didn’t start 
the discussion with Daan. No one asked him to begin characterizing me or the 
quality of my statements.

It’s because Daan chose to characterize me, and because his postings 
“evolved” to be more about me than about my topic,  that I claim that a more 
complete summary of this discussion, with some quotes, is justified. 
Obfuscation or successful misrepresentation is possible when the entire 
record isn’t summarized together, in one posting, as I do here. 
Cross-referencing spoils the effect of Dan’s misquotes, mis-statements, 
evasions and straw-man games. As I said before, I claim that I have a right 
to answer comments or characterizations about me. Because, this time, this 
posting’s comments will be adequately complete, I promise that this will 
_genuinely_ be my last posting here--unless someone else chooses to 
perpetuate the discussion by posting more statements to answer.

And I apologize again to the list for the length of this discussion. I don’t 
want to waste your inbox-space, and this will be my last posting here.

As I’ll show here, with quotations, Daan’s postings in this discussion have, 
from the start, consisted of evasions, mis-statements, misquotes, and rather 
shameless repetition of unsupported claims that he had already been called 
on. And, as is so often resorted to by someone who can’t support his claims 
on their own merit, Daan’s posts tend increasingly toward criticism of the 
person with whom he wants to disagree

Evasions? What’s the point of evasions in voluntary, unsolicited 
opinion-expression? Good question.

I started here merely stating a fault with data maps, and making the 
suggestion that maps intended to tell what is where should give the typical 
user a way to find out what is where. It seemed a simple, harmless, and 
uncontroversial thing to say. More specifically, nearly all map users, when 
they want to find or determine a lat/long position, do so by linear 
interpolation. Therefore there is good reason for a data map, if it is to be 
usable by typical map users, to let positions be accurately found or 
measured by linear interpolation. I had no idea what anger I was stirring up 
by that claim. I had no intention of getting into a contentious discussion.

So, first, let me quote Daan’s first comment about my statements:

Daan said:

Easily converting between map coordinates and spherical coordinates is one 
reason to choose a projection.

I comment:

Especially if the map is for the purpose of showing where something (species 
range, temperature zone, etc) is.

Daan says:

When a mapmaker decides that's the most important reason, the mapmaker does 
just what you suggest.

I comment:

No. He doesn’t. That’s the first of a series of mis-statements by Daan. I’ve 
never heard of a mapmaker using a graduated equidistant projection. I’ve 
never heard of a publisher of a modern-day data map using the equidistant 
elliptical (Apianus II). Even an ordinary equidistant cylindrical is quite 
rare (unheard of these days?) as a data map.

Daan continues:

Generally the mapmaker decides other factors are more important.

I comment:

There, Daan is merely repeating what I’d pointed out. I posted my message 
only because “generally the mapmaker decides that other factors are more 
important”. Daan’s point in repeating me? Who knows? The highest form of 
flattery?

I won’t quote or comment on Daan’s other postings line-by-line, as I did 
with this one. I wanted to show that Daan’s first posting in this discussion 
sets his tone and his discussion-level and conduct throughout. I’ll only 
quote the more brazen mis-statements and the ones that he relies on more.

In his next posting, Daan says:

Mike, I'd need to know a little more about what you mean by "data maps".

I comment:

That’s odd, because, even in my first posting, I clarified that I was 
referring to spatial distribution maps in atlases. Which part of that 
doesn’t Daan understand? Later I include nature guidebook species range 
maps. Is that part of the “evolving” positions that so terribly confuses 
Daan?

Daan says:

Most maps whose primary purpose is to show spatial distributions are 
expected to be equal-area.

I quote this because it’s the reason why I then suggested the sinusoidal as 
a compromise, because it’s both equal-area and linearly interpolable. Daan 
will then say that my addition of the sinusoidal equal-area compromise is an 
“evolution” of positions, and “as muddy as it gets.” I mention that here to 
tell why I quote his mention of equal area.

Daan continues:

Equal-area conflicts with equidistant.

I comment:

Yes, if “equidistant” requires straight meridians. But not if it just refers 
to parallels being equidistantly-spaced on the map. Then the sinusoidal is 
equidistant and equal-area. More importantly, the sinusoidal is both equal 
area and linearly-interpolable. Later Daan wants to make an issue of the 
meaning of “equidistant”, though it isn’t relevant to the value of the 
sinusoidal as a compromise between equal area and linear interpolability.

Next, Daan shows us another ridiculous evasion:

In your example of "zones of vegetation", there are the grossly defined 
"tropical", "temperate", and "arctic" zones, where latitude is the primary 
consideration. In those cases, precise distances mean little and the map's 
depiction of parallels is thought to suffice.

I comment:

I said at the outset that I was referring to spatial distribution maps in 
atlases. I doubt that a map of Daan’s three zones can even be found in a 
modern atlas. And I’ve never found an atlas climate or vegetation map whose 
zones were latitude bands. Perhaps Daan is ignorant of the fact that, at a 
given latitude, deeply continental climate is entirely different from 
coastal climate, and that east coast climate is entirely different from west 
coast climate. And that such things as altitude, rain-shadow effects, nearby 
ocean currents, and monsoon effects cause climate differences between places 
at the same latitude.

But even if atlases had any maps such as Daan describes, it would be a tiny 
fraction of an atlas’s vegetation and climate spatial distribution maps. And 
I was talking about spatial distribution maps in general, not just 
vegetation maps. This is an example of the old and dishonest straw-man 
technique. Why Daan would bother with such techniques and games, I have no 
idea.

Daan continues:

If you are referring to ground-cover maps of a continental or global scope, 
then I should think an equal-area representation would be paramount.

I comment:

But then, when I later, in reply, suggest the sinusoidal as an equal-area 
compromise, Daan calls that a confusing evolution of positions.

Daan continued:

If you are referring to large-scale ground-cover maps

I comment:

Large scale maps in an atlas? As I said, I clarified at the outset that I 
was referring to atlas maps. This could be another straw-man example, or an 
example of Daan’s technique of pretending to mis-understand something or 
miss something, so that he can evade by arguing with something that wasn’t 
said.

Daan continued:

, then the precise purpose of the map would strongly influence the choice of 
projection. In this last case, is the ease of determining the precise 
geographic coordinate of a point more important than accurate distances 
measured between any two points on the map? More important than precise 
directions anywhere on the map? More important than being able to overlay 
and compare against existing printed maps?

I comment:

I’d made it abundantly clear that I was talking about maps whose purpose is 
to show where various kinds of zones are. During the discussion I repeatedly 
pointed out that it would be difficult to find a scenario where someone 
needed accurate distances or directions from a bird book or a rainfall 
distribution map in an atlas. This was apparently always one of the “points” 
that Daan didn’t answer--while he kept on emphasizing the primacy of 
accurate distance.

As for overlays, again, I made it clear that I was talking about atlas and 
bird book maps, which don’t have overlays to lay over USGS maps, etc.

Daan continued:

Your thesis is really about the need for easy conversion from map 
coordinates to geographic coordinates.

I comment:

You catch on fast, Daan.

Daan continues:

I haven't got a good sense yet for why that need trumps the others.

I comment:

Well, how about because Daan has never answered my question about why a user 
of a bird book or atlas rainfall distribution map would need distances or 
directions from that map? …a map that is intended to show where a bird 
species is found, or where a certain rainfall zone is, so that you can 
determine which zone a particular place is in, or whether a particular bird 
can be found in a particular park or county.

In Daan’s next posting, he says:

Constant scale along parallels is not related to equidistance because 
parallels are not great circles. The shortest path between two points on a 
parallel is never the parallel itself unless the parallel is the equator.

I comment:

But I’d never said otherwise. Another example of Daan’s constant, persistent 
straw-man effort.

Without repeating my answers to Daan’s other statements in that posting, 
I’ll merely mention that this is the one where he says:

I can't really get into a whack-a-mole game of responding to each of your 
points only to have several more spring up in their places

I comment:

I had not been sending him a barrage of random whack-a-mole points, only to 
be replaced by new ones. Rather, I’d been merely answering Daan’s own 
statements.

My own “points” were few and consistent: The fact that a map for showing 
where certain zones are is of little use if typical users don‘t have an 
accurate way to find and determine positions on the map; the concession 
(after Daan insisted on equal area)  that some might want equal area for 
certain kinds of mapped data, for which the sinusoidal would then be a good 
compromise; and the fact that it would be difficult to come up with a 
scenario in which someone needs accurate distances &/or directions from a 
bird book range-map or a rainfall distribution map in an atlas.

In Daan’s next posting there are just a few brief things to mention. Here he 
makes an unsupported and unspecified charge:
your analysis of the issues surrounding your thesis seem to evolve as we 
talk. These make it hard for me to engage you in conversation.

Later he tells what it is that he claims has “evolved”. I quote this 
because, I quoted him in an earlier posting in which he advocated equal area 
for data maps. Below, he faults me for being inconsistent, or “evolving” 
when I mentioned an equal area compromise, in response to his claim that 
equal area is needed:

Dan says:

You started out claiming a "graduated equidistant" is the answer. You've now 
evolved to an "interrupted sinusoidal". That's about as muddy as it gets.

I comment:

Come again? What’s muddy about offering an equal area compromise when 
someone insists that equal area is needed? I mentioned interruption in 
connection with a world map, where sinusoidal is used because equal area is 
demanded.

In his last posting, I’ll just quote one statement:

Balderdash. You made no mention of the utility of equal-area in your 
original posting

I comment:

Nor did I advocate the utility of equal-area at any time in the discussion. 
I conceded that some might want equal area for some kinds of mapped 
information.. I compromised with the desire for it, by suggesting the 
sinusoidal as an equal-area compromise.

Daan apparently wanted to play the role of the patient (ersatz?) scientist 
doing his best to communicate with someone who wasn’t communicating 
co-operatively. When the facts don’t fit the scenario, that’s no problem for 
Daan, because Daan doesn’t mind mis-representing the facts to fit his 
desired role and his chosen scenario.

A few addenda:

1. Earlier I precisely defined the linearly interpolable positions property 
(LIPP)

I consider LIPP to be a useful way to say what it says.

But a briefer definition and name are possible. I don’t post this in order 
to replace LIPP with it. I merely add it as another way to say it:

A projection has the “linearity” property if, when a map is precisely 
constructed on that projection, it’s possible to divide that map into 
regions, throughout each of which the Y co-ordinate on the map varies 
linearly with latitude, and it’s possible to divide that map into regions, 
throughout each of which the X co-ordinate on the map varies linearly with 
longitude.

[end of linearity property definition]

For practical purposes that definition can be shortened by substituting 
“…it’s possible to divide the map into regions throughout each of which the 
Y co-ordinate on the map varies linearly with latitude and the X co-ordinate 
on the map varies linearly with longitude.”

[end of briefer linearity2 property definition]

Officially I’ll stick with the more general longer first wording. Often I 
might use the briefer second wording. Officially, I’ll call the second 
definition the definition of linearity2.

LIPP and linearity are both worthwhile ways of saying it, with different 
emphases in their definition and name.

2. I wouldn’t recommend the orthographic elliptical for an atlas or put it 
on the wall, because it’s more a picture than a useful map. And it has no 
measurement properties.

3. I don’t mean to imply that all maps should have the property that I 
advocate for data maps. What I’ve said about that applies only to species 
range maps in nature guidebooks and spatial distribution maps in atlases.

4. I don’t mean to imply that the only maps that should ever be published 
are those whose construction can be explained to everyone. Some people might 
want the properties of maps that they wouldn’t want to hear the construction 
explanation of, and wouldn’t care about the construction explanation. And 
some might care about the construction but also be familiar with it or 
willing to study it.

But I do claim that construction explainable to everyone is often an 
important and valuable attribute for a map, and one that cartographers don’t 
appreciate. Some people _would_ prefer a map whose construction can easily 
and briefly be defined to them.

Michael Ossipoff