Atlas

Current Goal:

• Build activity with world map with country names, capital names, and major cities, with internatinoalized labels.
• Work with pm27 + wikiwix to make mapping of Wikipedia data possible on top of the basemap.

Current activity:

• Building tiles + sugarizing an HTML/JS/OpenLayers based browser to browse those tiles into an activity.

Possible activity:

• Wednesday, Aug 22 IRC meeting with pm27/wikiwix to discuss next steps. (#olpc-content, irc.freenode.net)

65.77.47.4 16:10, 17 August 2007 (EDT)

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Some notes for available free map data.

• The Wikimedia Commons 'Atlas' is a constellation of maps with tags and origin/date/location information. They don't all have clear geotags or projection information or perfectly accurate dates, there is overlap and missing gaps, and they don't have an interface for browsing.

• OpenLayers and FeatureServer and TileCache are a useful toolchain for generating, rendering, and annotating maps, with strong support for open formats.
  • Free maps include a great one for Boston and a basic world map to show what it looks like with no tweaking.

Generating a fast static map

TileCache/MapServer will generate a set of tiles for you -- pick what sort of background you want from available default layers; how many levels deep you want to go; and whether you want the tiles to continue to exist at lower resolution for depeer zooms. The default package is 7 levels deep, starting with one for the entire globe, and has sea-topo, land-cover, country- & county-border, city-dot, basic roads & features, and <language>-name layers.

An atlas of ~100MB should offer good resolution for every country in the world. At each layer of tiles, defined regions on the map can be mapped to a dataset of html, images, or text.

Generating a dynamic map

First, install MapServer and related tools locally. MapServer 5 uses AGG rendering, which does a fine job of minimizing aliasing; it is still in Beta, but worth the extra effort to use by all accounts.

Next, find the layers you want to include in your tiles. Make sure they are all at the same resolution and format.

Define how to generate map tiles from data sources on a local or fast-connected server... test it out under a few standard use cases to make sure it is fast enough. Some rendering is done on the client, so check this under client load as well.

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