Tools to generates tiles from WMS or Mapnik, to S3, Berkley DB, MBTiles, or local filesystem in WMTS layout using Amazon cloud services.
Project description
The goal of TileCloud Chain is to have tools around tile generation on a chain like:
Source: WMS, Mapnik.
Optionally use an SQS queue, AWS host, SNS topic.
Destination in WMTS layout, directly on local filesystem, on S3 or MBTiles on local filesystem.
Feature:
Generate tiles.
Drop empty tiles.
Drop tiles outside a geometry or a bbox.
Use MetaTiles
Generate GetCapabilities.
Generate OpenLayers example page.
Obtain the hash of an empty tile
In future, measure tile generation speed
Calculate cost and generation time.
In future, manage the AWS hosts that generate tiles.
Delete empty tiles.
Get it
Install:
virtualenv buildout ./buildout/bin/pip install tilecloud-chain ./buildout/bin/pcreate -s tilecloud_chain .
Edit your layers configuration in ./tilegeneration/config.yaml.
Configure grids
The grid describe hos the tiles are arranged.
Especially on s3 be careful to choice every theres before generating the tiles. It possible that to change one of them you should regenerate all the tiles.
The resolutions in [px/m] describe all the resolution available for this layer. On raster layer have a look on the maximum resolution of the source files, it’s not needed to generate tiles in smaller resolution than the sources, it preferable to use the OpenLayers client zoom. Notes that you can add a resolution at the end without regeneration all the tiles.
The bbox should correspond to the resolution extent, to reduce where the tiles are generated use the bbox available on the layer.
The srs specify the code of the projection.
The unit unit used by the projection.
The tile_size in [px] default to 256.
The matrix_identifier default to zoom can also be resolution is how the z index is build to store the tiles, for example, for the resolutions [2, 1, 0.5] the used value are [0, 1, 2] it it’s based on the zoom and [2, 1, 0_5] if it’s based on the resolution. The second has the advantage to allows to add a new resolution without regenerate all the tiles, but it don’t work with MapCache.
Configure caches
There tree available tiles cache: s3, mbtile and filesystem.
The best solution to store the tiles is s3, mbtiles has the advantage to have only one file per layer - style dimensions. To serve the mbtile there is a view named serve_tiles.
s3 need a bucket an a folder (default to ‘’).
mbtiles and filesystem just need a folder.
On all the cache we can add some information to generate the url where the tiles are available. This is needed to generate the capabilities. We can specify:
http_url direct url to the tiles root.
http_urls (array) urls ti the tiles root.
http_url and hosts (array), where each value of hosts is used to replace %(host)s in http_url.
In all case http_url or http_urls can include all attribute of this cache as %(attribute)s.
Configure layers
First of all, all the attributes in layer_default are copied in all the layers to define the default values.
We have two type of layer: wms or mapnik.
To start the common attributes are:
The min_resolution_seed included minimum resolution that is seeded, other resolutions are served by MapCache.
The bbox is used to limit the tiles generation.
WMTS layout
To generate the files path sand the WMTS capabilities we need some additional informations:
The mime_type of the tiles, it’s also used by the WMS GetMap ant to upload the tile.
The wmts_style, default to ‘default’.
The extension is used to end the filename.
The dimensions (default to []) is an array of object that have a name, a default value specified in the capabilities, a value to generate the tiles, and an array of values that all the possible value available in the capabilities.
For example if you generate the tiles and capabilities with the following configuration:
dimensions:
- name: DATE
default: 2012
value: 2012
values: [2012]than with the following configuration:
dimensions:
- name: DATE
default: 2012
value: 2013
values: [2012, 2013]We will have two set of tiles 2012 and 2013 that booth are accessible by the capabilities, and by default we will see the first set of tiles.
Metatiles
The metatiles are activated by setting meta to on (by default it’s off).
The metatiles are used for two thing first to generate multiple tiles with only one WMS query by setting meta_size to 8 we will generate a square of 8 by 8 tiles in one shot.
The second usage of metatiles is to don’t have cutted label name, this is solved by getting a bigger image and cutting the borders. The meta_buffer should be set to a bigger value to the half size of the longest label.
Configure hash
We can filter tiles and metatiles by using an hash.
The configuration of this hash is in the layer like this:
empty_metatile_detection:
size: 740
hash: 3237839c217b51b8a9644d596982f342f8041546
empty_tile_detection:
size: 921
hash: 1e3da153be87a493c4c71198366485f290cad43cTo easily generate this configuration we can use the following command:
./buildout/bin/generate_tiles --get-hash <z/x/y> -l <layer_name>
Where <z/x/y> should refers en empty tile/metatile. Generally it’s a good idea to use z as the maximum zoom, x and y as 0.
Configure geom/sql
We can generate the tiles only on some geometries stored in PostGis.
The configuration is in the layer like this:
connection: user=www-data password=www-data dbname=<db> host=localhost
sql: <column> AS geom FROM <table>It’s preferable to use simple geometries, too complex geometries can slow down the generation.
WMS layers
The additional value needed by the WMS is the URL of the server and the layers.
The previously defined mime_type is also used in the WMS requests.
Mapnik layers
We ned to specify the mapfile path.
With mapnik we have the possibility to specify a data_buffer than we should set the unneeded meta_buffer to 0.
And the output_format used for the mapnik renderer, can be png, png256, jpeg, grid (grid_renderer).
Mapnik grid layers
With mapnik we can generate UTFGrid tiles (JSON format that describe the tiles present on a corresponding tile) by using the output_format ‘grid’, see also: https://github.com/mapnik/mapnik/wiki/MapnikRenderers#grid_renderer.
Specific configuration:
We have a specific way to drop_empty_utfgrid by using the on value.
We should specify the speudo pixel size [px] with the resolution.
And the layers_fields that we want to get the attributes. Object withe the layer name as key and the values in an array as value.
Il fact the Mapnik documentation say that’s working only for one layer.
And don’t miss the change the extension to json, and the mime_type to application/utfgrid and the meta to off (not supported).
Configuration example:
grid:
type: mapnik
mapfile: style.mapnik
output_format: grid
extension: json
mime_type: application/utfgrid
drop_empty_utfgrid: on
resolution: 4
meta: off
data_buffer: 128
layers_fields:
buildings: [name, street]Configure MapCache
For the last zoom levels we can use MapCache.
To select the levels we generate the tiles an witch one we serve them using MapCache we have an option ‘min_resolution_seed’ in the layer configuration.
The MapCache configuration look like this (default values):
mapcache:
# The generated file
config_file: apache/mapcache.xml
# The memcache host
memcache_host: localhost
# The memcache port
memcache_port: 11211
# The mapcache location, default is /mapcache
location: /${vars:instanceid}/mapcache
apache:
# Generated file
config_file: apache/tiles.conf
# Serve tiles location, default is /tiles
location: /${vars:instanceid}/tiles
# Expires header in hours
expires: 8To generate the MapCache configuration we use the command:
./buildout/bin/generate_controller --generate-mapcache-config
To generate the Apache configuration we use the command:
./buildout/bin/generate_controller --generate-apache-config
We can also use a buildout task to automatise it:
[buildout] parts: += mapcache [mapcache] recipe = collective.recipe.cmd on_install = true on_update = true cmds = ./buildout/bin/generate_controller --generate-mapcache-config ./buildout/bin/generate_controller --generate-apache-config uninstall_cmds = rm apache/mapcache.xml rm apache/tiles.conf.in
Configure S3
The cache configuration is like this:
s3:
type: s3
# the s3 bucket name
bucket: tiles
# the used folder in the bucket [default to '']
folder: ''
# for GetCapabilities
http_url: https://%(host)s/%(bucket)s/%(folder)s
hosts:
- wmts0.<host>The bucket should already exists.
Before running an operation on S3 don’t miss to set the following variable:
export AWS_ACCESS_KEY_ID=... export AWS_SECRET_ACCESS_KEY=...
Configure SQS
The configuration in layer is like this:
sqs:
# The region where the SQS queue is
region: eu-west-1
# The SQS queue name, it should already exists
queue: the_nameThe queue should be used only by one layer.
Before running the generation miss to set the following variable:
export AWS_ACCESS_KEY_ID=... export AWS_SECRET_ACCESS_KEY=...
To use the SQS queue we should first fill the queue:
./buildout/bin/generate_tiles --role master --layer <a_layer>
And then generate the tiles present in the SQS queue:
./buildout/bin/generate_tiles --role slave --layer <a_layer>
Generate tiles
Generate all the tiles:
./buildout/bin/generate_tiles
Generate a specific layer:
./buildout/bin/generate_tiles --layer=<a_layer>
Generate a specific zoom:
./buildout/bin/generate_tiles --zoom=5
Generate a specific zoom range:
./buildout/bin/generate_tiles --zoom=2-8
Generate a specific some zoom levels:
./buildout/bin/generate_tiles --zoom=2,4,7
Generate tiles on a bbox:
./buildout/bin/generate_tiles --bbox=<minx,miny,maxx,maxy>
Generate a tiles near a tile coordinate (useful for test):
./buildout/bin/generate_tiles --near=z/x/y
Generate a tiles in a deferent cache than the default one:
./buildout/bin/generate_tiles --cache=<a_cache>
And don’t forget to generate the WMTS Capabilities:
./buildout/bin/generate_controller --capabilities
Tiles error file
If we set a file path in config file:
generation:
error_file: <path>The tiles that in error will be appen to the file, ant the tiles can be regenerated with ./buildout/bin/generate_tiles --layer <layer> --tiles-file <path>.
Explain cost
Configuration (default values):
cost:
# [nb/month]
request_per_layers: 10000000
# GeoData size [Go]
esb_size: 100
cloudfront:
download: 0.12,
get: 0.009
ec2:
usage: 0.17
esb:
io: 260.0,
storage: 0.11
esb_size: 100
request_per_layers: 10000000
s3:
download: 0.12,
get: 0.01,
put: 0.01,
storage: 0.125
sqs:
request: 0.01Layer configuration (default values):
cost:
metatile_generation_time: 30.0,
tile_generation_time: 30.0,
tile_size: 20.0,
tileonly_generation_time: 60.0The following commands can be used to know the time and cost to do generation:
./buildout/bin/generate_controller --cost
This suppose that you use a separate AWS host to generate the tiles.
Configure SNS
SNS can be used to send a message when the generation ends.
The configuration is like this:
sns:
topic: arn:aws:sns:eu-west-1:your-account-id:tilecloud
region: eu-west-1The topic should already exists.
Before running the generation miss to set the following variable:
export AWS_ACCESS_KEY_ID=... export AWS_SECRET_ACCESS_KEY=...
Openlayers pink tiles
To avoid the OpenLayers red tiles on missing empty tiles we can add the following CSS rule:
.olImageLoadError {
display: none;
}To completely hide the missing tiles, useful for a transparent layer, or for an opaque layer:
.olImageLoadError {
background-color: white;
}OpenLayers test page
To generate a test page use:
./buildout/bin/generate_controller --openlayers-test
Configure and explain AWS
The generation can be deported on an external host.
Other usefull options
--verbose or -v: used to display info message.
--debug or -d: used to display debug message, pleas use this option to report issue. With the debug mode we don’t catch exceptions, and we don’t log time messages.
--test <n> or -t <n>: used to generate only <n> tiles, useful for test.
Important remarks
Especially on S3 the grid name, the layer name, the dimensions, can’t be changed (understand if we want to change them we should regenerate all the tiles).
By default we also can’t insert a zoom level, if you think that you need it we can set the grid property matrix_identifier: resolution, bit it don’t work with MapCache.
Please use the --debug to report issue.
From source
Build it:
python bootstrap.py --distribute -v 1.7.1 ./buildout/bin/buildout
Changes
Release 0.6
Now the apache configuration can be generated with ./buildout/bin/generate_controller --generate-apache-config, it support filesystem cache and MapCache.
Windows fixes.
Use console revrite (r) to log generated tiles coordinates.
Now if no layers is specified in generation:default_layers we generate all layers by default.
Now bbox to be floats.
New --get-bbox option to get the bboy of a tile.
Add coveralls support (https://coveralls.io/r/sbrunner/tilecloud-chain).
Add an config option generation:error_file and a command option --tiles-file to store and regenerate errored tiles.
Release 0.5
SQS config change:
layers:
layer_name:
sqs:
# The region where the SQS queue is
region: eu-west-1
# The SQS queue name, it should already exists
queue: the_nameAdd debug option (--debug), please use it to report issue.
Now the sql request can return a set of geometries in a column names geom but the syntax change a little bit => <column> AS geom FROM <table>
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