Posts Tagged ‘towns’

Preview of Natural Earth version 1.2 populated places

Tuesday, May 4th, 2010

Version 1.1 brought Natural Earth up to ~7,000 populated places (purple hollow circle icons with labels). Version 1.2 will increase that by 25 times to about 175,000 populated places. It will be available as a supplement to the 1.1 version selection. What does this get you? A 1:1 million scale map of cities around the world and a 1:250,000 scale map of the United States and other select countries. There’s still basic selection work to be accomplished (Santiago Chile has duplicate points now, as does London) and scale ranks need refining (boosting blue 10 million, 5 million and 2 million selections from the 1:1 million black dots on these preview maps).

Because the world’s geo infrastructure sucks, not all the new features will have population counts in the 1.2 version. But most should have areal extent bounds and nesting to indicate if the town is part of a larger metro area. At the 1:250,000 scale (gmaps zoom 11), we start to see actual incorporated towns and unincorporated suburbs, but at the 1:1m scale we’re still dealing primarily in metropolitan and micropolitan features (urban areas that host multiple “cities”).

The names of the feature will also need work, but that will occur after the 1.2 release (India, China, and Central Asia mostly). The version 1.1 locations will be shifted over to use the more accurate geoNames lngLats for about 6,000 features (note Oakland below). Locations were fine at 1:10,000,000 scale but don’t always hold up on zoom in. A later update will incorporate an additional 100,000 places to flesh out the 1:1m scale and maybe a few extra for closer in. Combine these populated places with roads and they start looking like atlas plates :)

More preview images after the jump.

sfbayarea

haiti

iraq

More preview maps after the jump.

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Natural Earth Vector Preview: Cities (Part 2)

Thursday, November 12th, 2009

Announced at NACIS in Sacramento, California in October, we’re closing in on final release of Natural Earth vector and raster map data.

Bill Buckingham wrapped up processing the Natural Earth Vector cities (populated places point locations) this week. I’ve been honing our admin-1 and admin-1 rankings and feature names (only 4,000 states and provinces around the world, wew!).

Bill’s added population estimates for each city based on LandScan. The technique allows the user to know both the relative “regional” importance of a town, regardless of it’s population, based on which map scales the feature should be visible (thanks to Dick Furno) at AND to know how many people live there.

By taking a composite of both, you can still show small population cities that are regionally important at a small type point size along with larger populated places at the smaller map scales.

We have about 6,500 cities in Natural Earth Vector. Over 90% of those have population estimates (the ones that don’t are usually out in the boondocks). Together, our cities capture over 3 billion people or half of humanity.

For comparison, most other populated place GIS files have only 2,000 some cities and they focus on country and first order administrative capitals with a bare smattering of other towns. For instance: Lagos, Nigeria or San Francisco, California.  This makes smaller countries with lots of administrative divisions (like Slovenia, Vietnam, or Jamaica) seems way more populated than larger countries with larger administrative divisions (like the United States). See the North America screenshot below for an example and look at the Caribbean versus United States.

They also don’t estimate populations, and if they do they use official census number that hide the true “metro”-style counting of people that should inform a thematic map regardless of formal administrative boundaries at the smaller map scales that Natural Earth excels at.

Now for some screenshots:

(Scale ranks, followed by population view color coded like the scale ranks with nodata green dots, then cyan dot version is ESRI cities overlayed)

0world_ranks

0world_population

1no_amer_ranks

1no_amer_population

1no_amer_esri

2us_ranks

2us_population

2us_esri

More continents o’ dots after the jump.

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