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New openstreetmap-carto with railway labels

Pubblicatu di Littlebtc lu 30 August 2017 n English

As the openstreetmap-carto updated, My pull request (#2687) now live on OpenStreetMap. Now the name from railway will be slightly rendered.

A three-level rendering is set (z11 for highspeed, z14 for main lines and z17 for all) to make it impact less to other elements.

After visiting Tokyo in July 2017, I found out that most of the rendering for OpenStreetMap is not that friendly to a railway-centric urban area, so I came with this request trying to fix that.

This is how Tokyo looks like, before and after, in z14:

Before Before

… See full entry

CJK in standard layer, too bold for now (FIXED)

Pubblicatu di Littlebtc lu 11 October 2016 n English

Update: Thanks Operations for blazing quick response, new FreeType is on the server and rendering should back to normal after cache invalidated.

:D

After the Noto CJK finally landed in the Standard layer, Boldness issue became a major problem for them.

Imgur

Investigation by ` vholten` proved it was caused by the old FreeType version (2.6.1) in the rendering server, but it seems there is no easy or safe way to fix the issue.

  • Converting to (Cubic) OTF to (Quadratic) TTF will take very long time and the result may not be loseless.
  • Upgrade newer FreeType via third-party PPA, or patch and build old FreeType from apt-get source will work, but dangerous and will become a maintenance hell.

Maybe we should give up on fixing it until we can get newer Linux distro?

PostGIS 2.2 rocks!

Pubblicatu di Littlebtc lu 11 February 2016 n English

Recently I had worked on a simple server that will import the bus stop data from the New Taipei City government and generate map tiles to be used in JOSM, as they seemed to change their license to be compatible. The result is now available on GitHub.

Imgur

Historically it was hard to implement a feature in the Transport Map: Group near bus stops with the same name. But after a lot of research, I found it is not hard again: PostGIS 2.2 added friendly spatial clustering functions!

So the problem can be mostly solved by one line SQL command now:

INSERT INTO ntpc_stop_group (convex_hull, name)
    SELECT ST_ConvexHull(unnest(ST_ClusterWithin(ST_Buffer(location, 0.0003), 0.001))),
        name from ntpc_stops GROUP BY name;

Use ST_Buffer to generate circles centered at every stops, use ST_ClusterWithin to place them into groups, finally using unnest and ST_ConvexHull to generate the resulting polygon.

The current result looks great and I think further optimization is still possible. :)

Celebrating Open Data Maps in Taiwan -- By Tracing it Hard

Pubblicatu di Littlebtc lu 28 August 2015 n English

The Open Data movement in Taiwan is growing fast. In July, after half year of discussions between authorities and communities, the data.gov.tw platform released a new, permissive, CC-BY convertible open data license. It is a game changer for the open data community, and now for the OpenStreetMap Taiwan mappers.

In this week, the National Land Surveying and Mapping Center, or the NLSC, announced open data edition of Taiwan e-Map under new open data license. The zoom level of the open data edition is limited to 1/18000 or z15, but it already contains a lot of data that is not available in any other sources.

Great quality of NLSC maps

And most importantly, the accuracy of NLSC maps is superior. Take a look at it with Strava Heatmap. It is accurate not only for the downtown: Downtown Taipei, NLSC + Strava

… See full entry

Locu: Tong'anzhai, Tongren Village, Yongjing Township, Changhua County, 51247, Taiwan