Crunching Data In GeoServer: Mastering Rendering Transformations, WPS Processes And SQL Views - FOSS4G 2016

Ing. Andrea Aime
Ing. Simone Giannecchini
GeoSolutions
Processing Data In GeoServer
With WPS And SQL Views

GeoSolutions
 Founded in Italy in late 2006
 Expertise
• Image Processing, GeoSpatial Data Fusion
• Java, Java Enterprise, C++, Python
• JPEG2000, JPIP, Advanced 2D visualization
 Supporting/Developing FOSS4G projects
 GeoServer, MapStore
 GeoNetwork, GeoNode, Ckan
 Clients
 Public Agencies
 Private Companies
 http://www.geo-solutions.it
FOSS4G 2016, Bonn
22nd - 26th August 2016

Some historical perspective
 Year 2008:
 Publish maps on the net
 Nice styling, maybe time/elevation based selector,
some little extra filtering
 Maybe some editing, some PDF printing
 Since 2013:
 All of the above, but…
 We can hardly make a new application without
some data processing in it
FOSS4G 2016, Bonn

WPS: some quick reminders
FOSS4G 2016, Bonn

Web Processing Service
 Wikipedia introduces OGC WPS as:
 [A service] designed to standardize
the way that GIS calculations are
made available to the Internet.
 WPS can describe any calculation
including all of its inputs and
outputs, and trigger its execution
 The specific processes served up by
a WPS implementation are defined
by the owner of that implementation.
 Although WPS was designed to work
with spatially referenced data, it can
be used with any kind of data.
FOSS4G 2016, Bonn

An Example
 Buffer a L shaped
geometry with
distance “2”
 Get the result back
as GML
FOSS4G 2016, Bonn

Synchronous vs asynchronous
WPS
client
WPS
Launch
process
Send back
results
Simple
Suitable for fast executions
Synchronous
WPS
client
WPS
Launch process
Status URL
Check progress
50%
Check progress
100%
Results inline
Link to results
More complex
Suitable for longer computations
Asynchronous
FOSS4G 2016, Bonn

Common WPS setup
WPS
Remote
WCS
Remote
WFS
HTTP
server
WPS
client
Request
+
data or links to data
Result
data
Fetch
data
FOSS4G 2016, Bonn

GeoServer WPS integration
WPS
Remote
WCS
Remote
WFS
HTTP
server
WPS
client
All GeoServer
Layers
WMS
clientWMS
GeoServer
UI
FOSS4G 2016, Bonn

Demo request builder
 List processes
 Describe
 Set parameters and
execute
 All in one form
FOSS4G 2016, Bonn

Rendering transformations
 On-the-fly data transformations inside rendering
chain
 Calling WPS processes from SLD docs
 Optimized for performance
FOSS4G 2016, Bonn

Let’s take one step back…
you don’t always need a WPS

Spatial DBMS!
• Never under-estimate the processing power of
your BDMS:
• Designed to efficiently juggle large quantities of
data
• Efficient spatial primitives (at least, in PostGIS)
• Doesn’t get more local to your data than this!
• Passing params down?
• Parametric SQL views!
FOSS4G 2016, Bonn

Parametric SQL views
WMS/WFS client
GeoServer
Spatial database
&viewparams=from:2000000;high:5000000
Expanded Query
FOSS4G 2016, Bonn

Parametric SQL views
FOSS4G 2016, Bonn
SELECT Date_part('year'::text, t1.obs_datetime) AS obs_year,
t1.storm_num, t1.storm_name,
t1.wind, t2.wind AS wind_end,
t1.press, t2.press AS press_end,
t1.obs_datetime, t2.obs_datetime AS obs_datetime_end,
St_makeline(t1.geom, t2.geom) AS geom
FROM storm_obs t1
join(SELECT storm_obs.id,
storm_obs.storm_num, storm_obs.storm_name,
storm_obs.wind, storm_obs.press,
storm_obs.obs_datetime,
storm_obs.geom FROM storm_obs) t2
ON(t1.obs_datetime + '06:00:00'::interval) = t2.obs_datetime
AND t1.storm_name::text = t2.storm_name::text
WHERE Date_part('year'::text, t1.obs_datetime)
BETWEEN %min_obs_year% AND %max_obs_year%
ORDER BY Date_part('year'::text, t1.obs_datetime),
t1.storm_num,
t1.obs_datetime
• Building lines of the fly from point data:

Enough theory
Let’s get down to business!

Soil Monitor
• Computing Soil Monitor Indeces at country level
• Soil Sealing
• Change Matrix
• GeoServer as the W*S Server
• MapStore as the mapping Front-End
• Webmapping and WPS Orchestration
• Charting
• GPU processing wrapper as WPS Processes
• JCuda
• Custom code to bridge between
GeoServer/GeoTools and Cuda
• Direct Ingestion of the resulting raster data
• Raster Algebra as rendering transformation using
Jiffle
http://www.soilmonitor.it/
FOSS4G 2016, Bonn
https://github.com/mbedward/jiffle

Soil sealing algorithm
FOSS4G 2016, Bonn

Change matrix results
FOSS4G 2016, Bonn

Charting what changed
FOSS4G 2016, Bonn

Tracking running processes
FOSS4G 2016, Bonn

Mapping Tuna Catches
• Multiple Filtering
• Aggregation
• Joining quartely
stats against the
grid
FOSS4G 2016, Bonn

Filtering, joining and aggregation
Some example control regexps:
• Y_INTERV:
• Default: 1
• Regex: ^(d)+$
• OP
• Default: sum
• Regex: ^[avg|sum]$
SELECT (T.TS_VALUE / %Y_INTERV%) AS TS_VALUE,
T.CD_TA_OCEANAREA, G.GEOMETRY
FROM
(SELECT CD_TA_OCEANAREA,
OP%(TS_VALUE) AS TS_VALUE
FROM FIGIS.TS_FI_TA
WHERE FIC_ITEM IN (%FIC_ITEM%)
AND CD_GEAR IN (%CD_GEAR%)
AND YR_TA IN (%YR_TA%)
AND QTR_TA IN (%QTR_TA%)
GROUP BY CD_TA_OCEANAREA
) t
LEFT OUTER JOIN FIGIS_GIS.GRID_G5 g
ON T.CD_TA_OCEANAREA = g.CD_OAREA
ORDER BY T.CD_TA_OCEANAREA
FOSS4G 2016, Bonn

Animation
• Animator tool
• GetMap + variying parameters + frame control
=> animated GIF!
• http://docs.geoserver.org/stable/en/user/tutoria
ls/animreflector.html
FOSS4G 2016, Bonn

Animator
• …/geoserver/wms/animate?request=GetMap&…
&format=image/gif;subtype=animated
&aparam=viewparams:YR_TA
&avalues=2000,2001,2002,2003,…
FOSS4G 2016, Bonn

Compunding WFS/WCS deficiencies:
Download services

Advanced Clip and Ship
• Community WPS module plus MapStore UI
• Requirements
• Download large amounts of data
• Generic data filtering
• Clip on polygon/bbox/circle, both vector and
raster
• Reproject to target CRS
• Band selection in raster
• Work in a cluster
• Solution: new WPS processes, asynch WPS
call
FOSS4G 2016, Bonn

MapStore GUI
Buffer process called synchronously when buffer size
changes
FOSS4G 2016, Bonn

MapStore GUI
Tracking download status (asynch WPS)
FOSS4G 2016, Bonn

Download service architecture
WPS
GeoServer
Layers
MapStore WMS
GetCapabilities
List of layers
Buffer
DownloadEstimator
Download
GetStatus
Fetch data
Status
database
Shared
Hazelcast/DBMS
database
FOSS4G 2016, Bonn

Pure WPS
calling to other computing nodes:
WPS Remote

WPS Remote
• Use GeoServer as WPS Broker  Run Remote
Processes Asynchronously
• Support Python or command line tools
• Relies on XMPP for discovery and
messaging/logging
• Supports Dismiss and basic load balancing for
different executors
• Automagic results ingestion in GeoServer
FOSS4G 2016, Bonn

WPS Remote
FOSS4G 2016, Bonn

WPS Remote  Change Detection
FOSS4G 2016, Bonn

Mixing parametric SQL views and WPS:
The Destination Project

Intro
Computing the risk of road accidents involving
dangerous goods (chemicals, petrol, gases and so
on)
Road segments
and stats about
car accidents
Human and environmental «targets»
Involved area,
depending on
type of good and
amount of
damage
FOSS4G 2016, Bonn

Large Data Volume
• Road network of good part of northern Italy
• Road divided into segments
• 100m portions (500k of them)
• 500m aggregation (120k of them)
• 1 km square cells (few hundreds)
• 51 buffer distances (depending on good,
scenario, level of damage)
• Several types of targets: schools, malls,
hospitals, populated areas, superficial and
underground acquifers, crops, woods, ….
FOSS4G 2016, Bonn

The road arc risk formula (s)
• Adding togheter the risk caused by the
different
• Arc own propension to accidentds
• Types of goods
• Human and enviromental targets
• The system allows to compute partial views of
the formula, either by selection of
targets/goods or by computing portions of it
• Has a number of coefficients that can be hand-
tuned by the caller
FOSS4G 2016, Bonn

The results, visually
• Rendering
transformation
• Read the
arcs/polys from
the DB, compute
their risk based
on the chosen
formula,
scenario, targets,
and coefficients
FOSS4G 2016, Bonn

How to compute it efficiently?
• Using SQL Views? No, the possible
aggregations variants are too many
• Using a pure Java process? No, too much data
to transfer from the DBMS
• Fully on the fly? No, too much data involved
•  Pre-compute all buffers and locate all
involved targets before hand (pre-cooked per
buffer risk)
•  Use a process that builds a final
aggregation query on the fly (dynamic sql
views)
FOSS4G 2016, Bonn

Parametric queries on steroids
• Find which queries are needed, replace params
• Some queries have sub-queries as params
FOSS4G 2016, Bonn

Efficient rendering tx
Risk
process
Queries
database
Arcs/Buffer
areas db
Map
renderer
Build overall
query, replace
params
Compute risk for
a batch of arcs
Raw arcs
Arcs + risk
• Compute risk on the
fly in the viewing
area
• Batch requests to
the BDMS to
minimize round-trip
overhead
FOSS4G 2016, Bonn

Efficient cross layer filtering
• Show only targets
involved in the
scenario under
study, e.g., the ones
crossing the buffer
areas where there is
significant risk
• Limit query to the
current bbox
FOSS4G 2016, Bonn

Efficient cross layer filtering
SELECT v_geo_popolazione_residente_pl.*
FROM v_geo_popolazione_residente_pl
WHERE v_geo_popolazione_residente_pl.fk_bersaglio_umano_pl in
(
SELECT distinct bersaglio.fk_bersaglio_umano_pl
FROM v_geo_popolazione_residente_pl bersaglio
join siig_geo_ln_arco_1 on
st_dwithin(bersaglio.geometria,
siig_geo_ln_arco_1.geometria,
%distanzaumano%)
WHERE siig_geo_ln_arco_1.geometria &&
st_makeenvelope(%bounds%, 32632)
)
This is a job for a parametric sql view
FOSS4G 2016, Bonn

Efficient computation of multi-buffers
• Computing 51 buffers
around each of 500k
arcs…
• Slow!
• Buffering over the
previous buffer proved
to be much faster than
computing each buffer
from the original arc
• Custom multibuffer
process
FOSS4G 2016, Bonn

Intro
• The Integrated Decision Aid (IDA) has been developed at the Centre for
Maritime Research and Experimentation (CMRE) in order to provide naval
exercise planners with an effective tool to assess risk to marine mammals
from acoustic transmissions.
• Assessment of potential hazard is performed through sound propagation
modeling available in the interface.
Sound
Propagation
Model
FOSS4G 2016, Bonn

Sound Propagation Model
• External Octave Matlab Process
• Logs the asynchrouns process status to the
DB as a Feature
Octave Matlab Script
for SPM
WFS
Follows the process
status through the
WFSWFSLog
Process allows
to insert and
update the
status of SPM
into the DB
Dynamically builds an external Octave
command line using the input parameters
through a FreeMarker Template (FTL)
FOSS4G 2016, Bonn

Sound Propagation Model
• The list of model runs is available on the bottom Data
Grid
• It is possible to get information on the input parameters
and execution from the WFS
FOSS4G 2016, Bonn

Raster Algebra Processes
• Simple Raster Algebra
• Gets an OGC Filter containing logical operations
between raster layers and produces a binary (0/1) layer
FOSS4G 2016, Bonn

• Advanced Raster Algebra using Jiffle
• Wraps Jiffle (http://code.google.com/p/jiffle/) in order to
execute complex Raster Algebra scripts against the
input layers
Jiffle is a scripting language for creating and analysing raster images. Rather
than having to write and test lots of JAI or Java AWT boiler-plate code to
access and manipulate images, Jiffle lets you concentrate on the interesting
bit: your algorithm.
Jiffle is being developed as part of the JAITools project.
Update 16 January 2013: Jiffle sources have moved to GitHub
FOSS4G 2016, Bonn

• Advanced Raster Algebra using Jiffle
• Gets an OGC Filter containing logical operations
between raster layers and produces a binary light layer
FOSS4G 2016, Bonn

• Raster Algebra detailed info
• Input parameters and outcomes are logged into WFS
• WPS Raster Stats Process provides statistics on the
coverages
Raster
Statistics and
Area in sq Km
Raster Algebra
Process user
inputs
FOSS4G 2016, Bonn

Utility Processes
• WPS Raster Stats process
• WPS Temp Cleaner async process
The WPS Raster Stats process can
be invoked at run-time.
It computes the Raster Stats on the
current viewport area.
A cleaner process has been created to
cleanup all the IDA temporary files.
Is invoked asynchronously and makes use
of the IDA config parameters.
Also a WFS Delete Transaction listener is
available cleaning up all the input and
temp files when removing a row from the
Data Grid.
FOSS4G 2016, Bonn

The End
Questions?
andrea.aime@geo-solutions.it
simone.giannecchini@geo-solutions.it
FOSS4G 2016, Bonn

Crunching Data In GeoServer: Mastering Rendering Transformations, WPS Processes And SQL Views - FOSS4G 2016

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