Posts Tagged ‘open geo data’

Haiti OpenStreetMaps + Google Map Maker

Thursday, January 21st, 2010

There are two camps opening up in the Volunteered Geographic Information (VGI or community generated content CGC) community that are sure to have big import going down the line. One is OpenStreetMap.org (editor | download) and the second is Google’s Map Maker (not available in the US and other developed world locations) (editor | tile view options | download). Both services allow users to either upload their own GPS track or digitize linework and points off satellite imagery. These two options have added to the global map, often creating the first detailed map of a place ever available to the general public.

But the two projects have very different license structures (OSM almost unrestricted, Google very restricted). Not only do they duplicate effort, but they result in “similar but different” products that do not perfectly register with each other. This is an problem that faced many in the US in the 1990s as many organizations developed their own, not-interoperable datasets for the same regions. That model has largely been replaced by single entities building fundamental datasets that other organizations and individuals repurpose.

The licensing and data coverage & registration issues are of note to professional cartographers (and first responders) more so then to the general public. But, as Sean Wohltman says:

OSM and MapMaker aren’t talking and I think it is a big problem – if you want to help rescue efforts in Haiti where do you go to digitize? OSM? MapMaker?

Muki Haklay has a good comparison of the detail in each of OSM and Map Maker for Haiti. In the map here, yellow means that there is a better coverage in Map Maker, and blue means that there is a better coverage in OpenStreetMap.
Screenshot below, click for larger version.

osm-mapmaker-haiti-180110

“The comparison looks at total roads length for both datasets. The calculated difference between them using the equation:

∑(OSM roads length)-∑(Map Maker roads length)

for each 1km grid square.

The information in the file can be used for the following applications:

  • Users of these mapping products - it can help in judging which dataset to use for each area.
  • Users – it can facilitate conflation -  the process of merging datasets to create a better quality output.
  • Mappers - it can illuminate which areas to focus on, to improve coverage.”

Sean Wohltman’s post Haitian Earthquake Emphasizes Danger of a Split Geo Community (seen over at FortiusOne’s Off the Map blog advocating for Creative Commons 0 “zero” licensing of geodata during disasters) has a overlay of OSM (Open Street Map) and Google Map Maker data.

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And finally, before and after images of OpenStreetMap.org map for Port-au-Prince, Haiti:

OSM just after the Earthquake

before4274264767_c9933d12c5

OSM Today

after4274264771_6873e16fa0

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Posted in Best practices, Data source, Geography, Google Map Mashup, Mapping, Promote | 2 Comments »

Introducing a new OSM editor… Potlatch 2 (Open Geo Data)

Monday, December 14th, 2009

[Editor’s note: This tool from the OpenStreetMaps.org cohort is open source and written in ActionScript 3.0. It displays OSM information in vector format for editing and tagging. Use it in concert with the MapZen iPhone app for capturing points of interest (POI) in the field.]

Republished from OpenGeoData. Nov. 30, 2009.

OpenStreetMap users will know all about Potlatch, the online editor that appears when you click the ‘Edit’ tab on the site. Well, there’s a whole new version coming soon!

Potlatch 2 is a complete rewrite still with the same principle in mind: an editor which hits the right balance between speed, ease-of-use, and flexibility. It’s under very active development at the moment and I’ll include a link at the end of this post where you can have a look.

But there are four big new features – and one behind-the-scenes change – to tell you about first.

New feature – friendly tagging system

Potlatch 2 has a friendly, intuitive tagging system. The mapper can use graphical menus, dedicated fields, and icons to get the tagging just right – without the need to remember tag names and values.

For example, you can choose highway types from a set of icons, then add a speed limit by selecting the appropriate restriction sign.

Potlatch 2 tag editor

All this is fully customisable using a straightforward presets file. Using this, you can create your own favourite tag combinations.

New feature – WYSIWYG rendering

Potlatch 2 has an all-new rendering engine far in advance of the current one.

With road names, patterned fills, rotated icons, and much more, the editing experience can be like working live on the familiar Mapnik rendering, the cyclemap, Osmarender, or anything you like -making it much more approachable for the beginner.

The Halcyon renderer used in Potlatch 2

Just like the tagging, the rendering is easy to customise. It uses a special form of CSS, called MapCSS, which lets you create wonderful-looking maps with just a few lines of text. The tagging and rendering together make Potlatch 2 ideal for ‘vertical’ mapping applications, such as a cycle-specific editor or a building/addressing editor. Stylesheets aren’t just about making the map look pretty: you can create stylesheets to help your mapping, such as one that highlights roads without names.

The rendering engine (Halcyon) is available as a compact (<100k) standalone component which you can embed in webpages, so your custom maps can be used outside Potlatch 2.

Continue reading at OpenGeoData . . .

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