Posts Tagged ‘tagging’

Exploring Place through User-generated Content: Using Flickr to Describe City Cores (Spatial Info Sci)

Monday, August 9th, 2010

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[Editor's note: Good focus on vernacular geography, on how we name and describe space, with a particular focus on downtown city cores explored thru millions of photos on Flickr. "Importantly, it deals with regions which are typically not represented in formal administrative gazetteers and which are often considered to be vague." Never seen Flickr geography before? Check out Aaron's flickr shapetiles (map), shpfile browser, and geotagger world atlas.]

Republished from the Journal of Spatial Information Science.
By Livia Hollenstein and Ross Purves

Terms used to describe city centers, such as Downtown, are key concepts in everyday or vernacular language. Here, we explore such language by harvesting georeferenced and tagged metadata associated with 8 million Flickr images and thus consider how large numbers of people name city core areas. The nature of errors and imprecision in tagging and georeferencing are quantified, and automatically generated precision measures appear to mirror errors in the positioning of images. Users seek to ascribe appropriate semantics to images, though bulk-uploading and bulk-tagging may introduce bias. Between 0.5–2% of tags associated with georeferenced images analyzed describe city core areas generically, while 70% of all georeferenced images analyzed include specific place name tags, with place names at the granularity of city names being by far the most common. Using Flickr metadata, it is possible not only to describe the use of the term Downtown across the USA, but also to explore the borders of city center neighborhoods at the level of individual cities, whilst accounting for bias by the use of tag profiles.

Continue reading via their PDF . . .

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 . . .