Posts Tagged ‘map scale’

read-write mapping: NACIS Conference Keynote by Michal Migurski of Stamen Design

Thursday, October 15th, 2009

[Editor's note: I'm just getting back from the annual NACIS conference and decompressing from backpacking, family and friends in the Golden State. Our great keynote speaker this year was Michal Migurski of Stamen Design who talked up the OpenStreetMap project. Mike has also been kind enough to help out with the Natural Earth Data site which will go live in another couple weeks once Tom and I have polished the data. Without further ado, the keynote...]

Republished from tecznotes.

[clip] I used the opportunity to talk about the fascinating OpenStreetMap project, specifically the ways in which it’s useful to a cartography audience and how that audience could benefit the project. This last thing in particular is what I closed with: I think the online face of OSM’s rendered tiles could use serious input from the NACIS community, particularly at the kinds of medium scales where the highly-detailed data blurs into “features”. Much of this happens by-hand in tools like Adobe Illustrator from what I can tell, a very different workflow from the industrial automation offered by my favorite stand-by, Mapnik.

This is a talk about a new awareness of maps and geography, and a change in attitudes toward maps.

I’m going start with a small detour here to tell you about an online phenomenon that’s going on four or so years now, called Unboxing. Unboxing is a kind of geek striptease, described in one site’s tagline as a “vicarious thrill from opening new gear”.

Unboxing is a response to the meticulous packaging of modern electronics gear, most notably Apple’s range of iPods, iPhones, and Mac computers – careful design is invested in the packaging, and careful appreciation is invested in its removal.

Why unboxing? Two aspects of the trend seem relevant here.

First, it’s a new kind of visibility into the fan club culture around popular electronics, allowing users to elevate their own appreciation of a mass-market good into a social experience. I remember bicycling past the Apple Store and the Cingular store on San Francisco’s Market St. on the day the iPhone was released. There were enormous lines in front of each, and as customers picked up their new iPhones they’d walk out the door, break into a jog, and high-five the remainder of the line. The division between fan and star here evaporates.

Second, the delivery mechanism for this fan-produced culture tends to be online sharing sites like Flickr and YouTube. Both are examples of the phenomenon of the “Read Write Web”, the now-familiar pattern of web-based communities formed around the creation and sharing of social objects like photos and videos.

One effect of these online communities is a new and durable awareness of the process behind creative production. Pages on Flickr or YouTube follow a pattern you’re probably familiar with: title in the upper-left, main “thing” just below that, and to the right at the same level of importance, the person who made it for you. Responsibility and provenance along with all the messiness and point-of-view are built-in assumptions.

In the world of text, we see this same pattern on Wikipedia.

This is the History Flow project from Martin Wattenberg and Fernanda Viegas at IBM, which shows edits to a single Wikipedia article over time as threads and contributions from a group of editors.

Like this one, each article has been beaten into shape over time by a group of people following loose rules of cooperation, so each page has an associated “Talk” page where you can peek into the arguments and negotiations connected to the particular set of facts represented there. You can see the sausage being made. You can also cause the sausage to be made, as we saw with Stephen Colbert’s parody of consensual reality he called “wikiality” and used to make occasional, abusive, hilarious forays into Wikipedia.

This is where we segue into geography.

Around 2004 or so, UK developer Steve Coast started a project called OpenStreetMap, the Wiki world map. Steve was connecting a few emerging threads: the falling cost of GPS hardware since it was made available for civilian use in 1996, the dismal copyright layer wrapped around Ordnance Survey maps, and the lack of a viable crappy-but-free alternative in the UK. It’s hard to overstate how crazy this idea was at the time; everyone knows that collecting worldwide geographic data at the street level is a massive undertaking, out of reach of an enthusiast community like the OSM of the time.

What was the state of online mapping at the time? Not terrible, but not great.

Continue reading at tecznotes  . . .

Bounding Boxes for World Countries (Berkeley GADM)

Tuesday, June 23rd, 2009

[Editor's note: Knowing the longitude-latitude (latLng) bounding box of a feature gives us a clue as to what map scale or zoom level is required to fit the feature into our display area and thus what base map scale set to draw from. While this image does not provide actual coordinates, it visually establishes what such bounding boxes look like (further refinements can be had with respect to crossing the 180° meridian, note New Zealand). ]

Republished from Berkeley GADM (Global Administrative Areas).

Here is a map of all countries and their bounding boxes (when using a lat/long “projection”), highlighting those countries that cross the international date line, and for which these bounding boxes make little sense (this map is provided for diversion only).

insidethebox

First Look at Natural Earth Vector

Friday, June 12th, 2009

Tom Patterson and I collaborated on the precursor to his first Natural Earth Raster project several years ago and we now preview Natural Earth Raster + Vector, a new free product due Fall 2009 that complements and expands on the previous work by providing detailed GIS linework at the 1:15,000,000 (1:15 million) scale and new versions of the raster product (including cross-blended hyspometric tints). The Washington Post, where I work, is contributing 2 more vector GIS base maps at the 1:50m and 1:110m scales and new versions of Natural Earth Raster will be released for those scales. This is a NACIS and mapgiving co-branded product with assistance from the University of Wisconson-Madison cartography lab, Florida State University, and others.

Please attend the October NACIS 2009 map conference in Sacramento, California for the unveiling.

More description and preview images after the jump.

(more…)

How Can You Tell What Map Scales Are Shown For Online Maps? (ESRI)

Wednesday, May 27th, 2009

scales_table

[Editor's note: I'm working on a group base map project that will be released in October that is for mapping at the 1:10,000,000 (1:10m) scale and smaller (regional continental to global at small print dimensions). I want this data to be easily used with online mapping services, but converting Google map tile set "levels" to natural scale equivelants isn't obvious. I remembered seeing this table at last year's NACIS conference in Missoula, Montana. Charlie Frye was kind enough to remind me where to find it on the ESRI site.]

Republished from ESRI Mapping Center.

As you zoom in (or out) of the online maps you see on Virtual Earth (VE) or Google Maps (GM), you are actually seeing a series of different maps with slightly different information displayed at each zoom level. Zoom level is indicated and controlled in an online map by the vertical zoom slider, like the one shown at the left in the image here. Whenever the zoom level is changed, a different map is shown.

Of course, these maps are well designed so that viewers are largely unaware that they are seeing these different maps. The foundation for good design of an “online map” hinges on understanding how to design for each of the zoom level represented in the entire online map. Colors, fonts, number of and types of features, etc. are all seriously considered when each of the maps is created for each of the zoom levels.

When authoring this kind of online map with ArcGIS, a map document containing group layers, one for each zoom level, is a good approach. (The Working with layers and scale ranges blog entry provides a good overview of how to organize a map document this way.) Each zoom level in the online map is represented by your work at a specific map scale in the ArcMap document. The hard part is to figure out which zoom level matches to which map scale. There are twenty zoom levels for Virtual Earth or Google Maps. The corresponding map scales that you would design and create your maps at if you wanted them to mash up on VE or GM are:

Continue reading at ESRI Mapping Center . . .

Map Scale Calculator Tools? (Kelso)

Monday, December 15th, 2008

Do you know of any good tools for converting a map’s graphic scale bar measurement to a representational fraction (RF)? Please share them! We often think of maps as 1:24,000 or 1:1,000,000 natural scale but more often than not a scale bar is the only indication of scale we have on a map. How to convert that back to the more familiar representational fraction?

What are the features and interface you’d like to see for such a tool?

The best that I’ve been able to dig up is:

From Oregon State University Library
http://oregonstate.edu/~reeset/html/scale.html

Type in the number of units per distance (or distance per unit) and it’ll return the relational fraction. It does not do a very good job allowing you to type in both the units and the distance as variable. I hardly ever find scale bars on maps that are exactly an inch long. So involves some pre-math to get this tool to work.

Screenshots below:

This University of Texas site does the opposite:
http://www.beg.utexas.edu/GIS/tools/scale2.htm

Enter the representational fraction of the map and get “1 inch = X miles” verbal statements where the left and right terms do not have the same units.

Then there is the general problem of converting between map units.

Google provides the most ready answer:
Type in “convert 12 miles to km” and it will return the conversion.

The same OSU site also has a version:

Read more about map scales.

Some example map scales and worked formula examples from Richard Layton (source).

  • 1 inch equals 10 miles
  • 1 inch = 10 miles
  • 1 inch = 10 miles x 12 inches/foot x 5280 feet/mile
  • 1 inch = 10 x 63360 inches = 633,600 inches
  • 1:633,600

To convert from RF to Verbal Scale you convert the fraction to familiar units of measurements; for example:

  • 1:250,000
  • 1 inch = 250,000 inches
  • 1 inch = 250,000 inches [d] 12 inches/foot = 20,833.3 feet
  • 1 inch = 20,833.3 feet [d] 5280 feet/mile = 4 miles or
  • 1 inch = 250,000 [d] 63360 inches/mile = 4 miles
  • 1 inch equals 4 miles

[Note: [d] = divided by]

SOME COMMON SCALES. Here is a list of RF scales commonly used in the Map Collection and their equivalent Verbal Scales.

  • 1:24,000 - 1 in. = .379 mi.
  • 1:62,500 - 1 in. = .986 mi.
  • 1:100,000 – 1 in. = 1.578 mi.
  • 1:250,000 - 1 in. = 4 mi.
  • 1:500,000 - 1 in. = 7.891 mi.
  • 1:1,000,000 – 1 in. = 15.783 mi.

For example you want a map of Arizona on a 8 1/2 x 11 inch piece of paper. To allow for 1/2-inch margins the new sheet will then be 7 1/2 x 10 inches. Since Arizona’s north-south dimension, 395 miles, is slightly longer than its east-west dimension, 340 miles, we will place the longer north-south dimension along the longer 10-inch dimension of the paper. The next step is to compute the scales for both dimensions of the State. The smaller of the two scales will be the one we need.

North-south
10 in = 395 mi
10 in = 395 mi x 63360 in/mi
10 in [d] 10 = 25027200 in [d] 10
1 in = 2502720 in
1:2,502,720

East-west
7.5 in = 340 mi
7.5 in = 340 mi x 63360 in/mi
7.5 in [d] 7.5 = 21542400 in [d] 7.5
1 in = 2872320 in
1:2,872,320

[Note: [d] = divided by]

We therefore need a map of Arizona at a scale of 1:2,872,320 or less to place it on an 8 1/2 x 11 inch sheet of paper.

Scale

Miles/inch

Line
Width on Ground*

Examples

1:2,000,000

~32

2000’

USGS
Nation-wide maps

1:1,000,000

~16

1000’

National and
state maps

1:500,000

~8

500’

State or
regional maps

1:250,000

~4

250’

US Army Map
Series

1:100,000

~1.6

100’

USGS 30′
quads

1:62,500

5208 feet

62.5’

USGS 15′
quads

1:24,000

2000 feet

24’

USGS 7′
quads

1:15,840

1320 feet

15.84’

Soils

1:9,600

800 feet

Aerial
photos

*Approximate real width on ground of a pencil line on a map – harder pencils give a finer line

1:2,000,000 to about 1:250,000 are SMALL-scale maps. Items on these maps appear small (e.g. a county on a 1:2,000,000 map is much smaller than on a 1:100,000 map).

1:24,000 on towards 1:9,600 are LARGE-scale maps. Items on these maps appear larger. 1:100,000 are
pretty much in the middle – intermediate scale.