The document outlines performance optimizations for Mapnik 2, detailing improvements in areas such as geometry storage, rendering pipeline, and data sources. Key enhancements include faster raster reprojection, anti-aliased line rasterization, and the introduction of new data handling options like memorydatasource and shapefile mmap. The release of Mapnik 2 is set for the following week, after over a year of development, with various new features aimed at improving efficiency and flexibility in styling and rendering.

1. Mapnik 2
Performance Optimizations
Dane Springmeyer | Development Seed
Sunday, September 11, 2011

2. Breakdown
• Core (rendering pipeline)
• Vector Output
• Datasources
• Image encoding
• Styling
Sunday, September 11, 2011

3. Geometry Storage
faster, more memory efficient allocator
japan quake / massive landuse polygons
why tile.osm.org is already running mapnik
trunk
Artem/MapQuest contribution
type: core
Sunday, September 11, 2011

4. Spirit2 Parsing
Grammer based string parsing
(expressions, filters, colors, wkt, dbf, svg
transforms)
Artem / Weait Contribution
type: core
Sunday, September 11, 2011

5. Proj4 reprojection
Leveraging lock-free transforms if >= 4.8
4.8 not yet released so you need proj trunk
Tom Hughes - Mapnik London 2010 sprint
type: core
Sunday, September 11, 2011

6. Raster
reprojection
New and fast: mesh based interpolation
Alberto Valverde - MeteoGrid/Madrid
type: core
Sunday, September 11, 2011

7. Faster AA lines
New option to use 2-3X faster anti-aliased
line rasterization:
<LineSymbolizer rasterizer=”fast” />
Drops short segments, less precise line
caps/joins
type: core
Sunday, September 11, 2011

8. Label Placement
Faster math
New options for fast placements or return
early (minimum-path-length)
Konstatin Kaefer / Herman Kraus
type: core
Sunday, September 11, 2011

9. Clang support
2x speed of compiles than gcc
Supports link-time optimization (gold linker
and libLTO)
type: core
Sunday, September 11, 2011

10. MetaWriters
Metadata collected during image rendering
(in same pass).
Can be output as GeoJSON or streamed
using mapnik::memory_datasource
Hermann / GSOC project
type: vector output
Sunday, September 11, 2011

11. grid_renderer
Highly optimized hit grids encoded as utf8
feature id’s in json
Invisible, tiled interactivity
http://developmentseed.org/blog/2011/sep/
07/see-how-utfgrid-works-visible-map/
type: vector output
Sunday, September 11, 2011

12. MemoryDatasource
Dynamic, direct in-memory creation to
render from http/json (think couchdb)
type: datasources
Sunday, September 11, 2011

13. Other new Plugins
rasterlite (wavelets in sqlite)
mongodb (experimental: github/
springmeyer)
type: datasources
Sunday, September 11, 2011

14. Postgres pool
Fixed to allow fuller utilization and benefit
of pg connections between many threads
type: datasources
Sunday, September 11, 2011

15. Shapefile mmap
Ultra fast shared memory-mapped region
cache - > 5x faster i/o
Artem / FOSS4G “WMS Shootout”
type: datasources
Sunday, September 11, 2011

16. SQLite
* rtree indexes
* shared cache
* fast, lock free access between threads
(Almost as fast as shapefiles now in mapnik)
type: datasources
Sunday, September 11, 2011

17. PNG Size and Speed
* faster, more flexible png quantiziation
* fixed palettes - ultra fast color reduction
(save on encoding time without quant cost)
* direct access to zlib fast compression
type: image encoding
Sunday, September 11, 2011

18. Filter-mode=first
Option on <Style /> to break after first rule
match
Critical for CSS support and avoiding
combinatorial explosion
type: styling
Sunday, September 11, 2011

19. Feature Caching
Option on Layer:
<Layer feature-caching=”true”/>
Allows re-use of features within layer with
multiple styles (road-casing)
type: styling
Sunday, September 11, 2011

20. Expressions
framework for runtime evaluation of styling
properties
<PolygonSymbolizer color=”[field]” />
type: styling
Sunday, September 11, 2011

21. Raster Colorizer
framework for runtime evaluation of styling
properties
<RasterSymbolizer>
<RasterColorizer default-mode="discrete" default-color="white" >
<stop color="#222222" value = "0" mode = "linear" />
<stop color="#EEEEEE" value = "25" />
</RasterColorizer>
</RasterSymbolizer>
type: styling
Sunday, September 11, 2011

22. Carto
New CSS language/parser (js, C++)
Inherits features of less.js (variables,nested
styles,mixins)
type: styling
Sunday, September 11, 2011

23. SVG Support
SVG rendering of icons
Gradients, transforms (rotate/scale/shear)
http://developmentseed.org/
type: styling
Sunday, September 11, 2011

24. Mapnik 2 release
• Next week, more than a year in process
• Try now:
sudo add-apt-repository ppa:mapnik/nightly-trunk
sudo apt-get update
sudo apt-get install libmapnik2 libmapnik2-dev mapnik2-utils
• Learn more: http://trac.mapnik.org/
milestone/Mapnik%202.0
Sunday, September 11, 2011

25. Thank you!
Dane Springmeyer
twitter/springmeyer
github/springmeyer
Sunday, September 11, 2011