h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: Scale - A803981
Author: Gordon the Scout, Keeper of Postal Codes and Maps No One Can Re-fold Properly (From Ottawa? Visit A799914!) (Be a CAMEL: A965810 - U198614

This was going to be part of my uni project on Geographic Concepts, but that fell to the wayside several months back.

Comments appreciated!

Share and Enjoy!

Absoluetly fine, but for one minor niggle:
'So, if a distance of 1km in the real world is represented by 10 cm on the map (scale of 1:1000) and by 1cm on another map (scale of 1:10000), the 1:1000 scale map is a larger scale map than the 1:10000 scale map. '

1km to 10cm is 1:10,000! 1km to 1cm is 1:100,000!

I was staring at that last night when I submitted it and I thought "hmm... that doesn't look right". Thanks for pointing it out!

It's easier if you put commas in between the zeros.

There are two schools of thought on commas in numbers. When I was in school and Canada was converting to the metric system, I was taught to use spaces rather than commas in numbers. (This, of course, conflicts with the numerical standards that are used where I work, at least for publications in English.) I don't know what the standard is in H2G2, but I'm sure the sub will sort that out if they feel it's necessary.

Scale models anyone?

You might want to mention that 2D maps is not the only objects with given scales. Good entry!

One question came to me:
I think it's really tricky to try to remember how many centimeters in a kilometer, and have to do the calculation each and every time I need it. (I don't use maps much.) How on earth do people who think in inches and miles manage?

Brilliant entry, Gordon. I'll let you know if I think up any useful suggestions.

(By the way, did you see this thread? F96164?thread=260791)

RhoMuNuQ

I think the answer to your question, although not quite 'on earth' can be found here:

http://whyfiles.org/101spaceflaw/


I would just like to complain that 'confusion of metric and English measurements' irritates me something rotten. Us English scientific types use SI units virtually everywhere now, but still have to deal with crazed american engineers who insist on using feet, gallons, and who knows what else to measure something. For Zarqon's sake, if you must use old imperial units, please stop referring to them as 'English' (especially when you guys can't work out what size a gallon should be anyhow).

Mind you, I agree with (real, warm) beer coming in pints.

Meanwhile, back at the article, I'd add gaps above and below the headers, and definitely space or comma seperate the long numbers into groups of three digits. (SI standard is spaces, but commas are popular too), and mention the scales used by the Ordnance Survey. The old maps used to be 'One Inch Maps' with a scale of one inch to one mile. That equates to 1:63360, newer maps, such as the LandRanger series at 1:50,000 and the Explorer range at 1:25,000 (i.e. 4cm = 1km)

Ordnance survey being a government agency, I don't know whether a link to them would be commercial in nature, but you can find them at http://www.ordnancesurvey.gov.uk/

Jim

I've put a footnote in about 3D scale.

I'll think about putting in a list of common map scales. I'm not familiar with the Ordnance Survey map products, but their products must be similar to the products of other national mapping agencies.

Thanks for the comments!

Oh, yes, and I put non-breaking spaces in the numbers, per the SI standard.

Good, using the suggested comma would have confused those of us who're unfortunate enough to use that as the decimal point.

Using EG standard tags around your paragraphs will take care of the mentioned need for spaces before and after headers.

> would have confused those of us who're unfortunate enough to use that as the decimal point

Don't get me started on people who send me comma-seperated value data files with commas for both delimiters and decimal points. Must.. control.. fist.. of.. death..

Another type of scale you haven't mentioned, is that used on graphs, particularly oddities like log scales. Things like dB are log scales (every six dB doubles the sound level). I'm not sure about the Richter scale (or even if that's how you spell Richter) or the whatever-scale used to measure wind speed (such as gale force 8, storm force 10, etc.)

Ah, but this entry is about that one definition of scale. Scientific scales of all kinds are a different matter altogether. My dictionary has four noun and three verb definitions for scale (each of them with multiple sub-definitions), and this entry should stick to the sense:
"a proportion between two sets of dimensions (as between those of a drawing and its original)"

This entry was originally going to be a part of my uni project on geographic concepts, so it's really about scale as it applies to maps. Scientific scale would be an excellent topic for an entry if someone wants to do it.

Are there other changes to be made?

Well... actually...

I think the 'large scale, small scale' bit needs reworking. You say it's subjective, then explain under 'large scale' that 'larger', when refering to scale, means features in nature take up more space on the map than they would on a map with 'smaller scale'. But then instead of defining 'small scale' as the same just opposite you go and set a definite point. '10 000 000:1 one is small scale'. Which it is in most instances, but it is, for instance, a fairly large scale globe. (I checked and found that mine is 14 666 666:1... at least that's the figure I got. )

I think that bit should go something like this:

-large scale - small scale is subjective and 'relative'

-larger means the real world takes up more space, and more detail from the real world is available, smaller obviously then means the opposite

-then explain that large and small scale depends on the application: a small scale driving map of london is a uselessly large scale map of southern England. The pages in your atlas are large scale maps of Earth, but insanely small scale maps for someone running orienteering.

Post 7 still applies.

RhoMuNuQ

Hi,

I'm pretty sure that an increase of 3dB represents a doubling of power. We refer to "3dBs down" as being the half power point anyway.

Awu

Not that it matters for this entry, but 3dB represents doubling, yes. (I've checked with my trusty calculator.)

Hi Again,

Maybe outside of the scope of your entry, but you have to be very careful taking measurements off of a map that is Mercator projection. Especially if it covers a large range of latitudes.

Because the Mercator projection distorts the horizontal scale**, you should take your measurements off the vertical (latitude). One degree of latitude is always 60 nautical miles.

There might be a scale bar on such a map/chart. If so, it represents the scale at around the center of the map's range.

Is a scale always a ratio? What about Beaufort?

Awu.

**Naomi James didn't know that either!