Web Processing Service:
The Final Frontier For Web GIS
Mike Pumphrey
April 25, 2012
Web Mapping is cool
• Serve data to anyone with a Net
connection
• Create pretty/informative
interactive maps
• Integrate maps and
software/interfaces
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Q: So why does anyone still
use Desktop GIS software?
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A: Web Mapping != GIS
“It looks nice, but can I determine viewsheds?”
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The End
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The End
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Benefits of web-based anything
• Distribution of time
• Distribution of energy
• Distribution of content
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OGC services (review)
• Web Map Service (WMS)
• Web Feature Service (WFS)
• Web Coverage Service (WCS)
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Introducing:
Web Processing Service
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WPS Definition:
“[WPS] provides rules for standardizing how
inputs and outputs (requests and responses)
for geospatial processing services ... The
standard also defines how a client can request
the execution of a process, and how the output
from the process is handled.”
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Translation:
You can do analysis over the web.
(Cool!)
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How Does It Work
• Processes exist on a server
• Request comes from client
• Server executes and outputs
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Just Like Other OGC Services
• GetCapabilities (GetCapabilities)
• DescribeProcess (DescribeFeatureType)
• ExecuteProcess (GetFeature)
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What About Data?
• Can be POSTed (ugh)
• Can be stored on the server (yay!)
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Data on server = interesting!
• That's where things get interesting!
• Operate on data stored on the server and
return to the client
• Operate on data stored on the server and
save on the server
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GeoServer has WPS support
• Available as a GeoServer community extension
• Alternately, core component in OpenGeo Suite
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GeoServer:
GUI interface for WPS
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Unavoidable example:
Point Buffer
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POLYGON ((2 0, 1.9753766811902755 -0.3128689300804617,
1.902113032590307 -0.6180339887498948, 1.7820130483767358 0.9079809994790935, 1.618033988749895 -1.1755705045849463,
1.4142135623730951 -1.414213562373095, 1.1755705045849463 1.618033988749895, 0.9079809994790937 -1.7820130483767356,
0.6180339887498949 -1.902113032590307, 0.3128689300804618 1.9753766811902755, 0.0000000000000001 -2, -0.3128689300804616 1.9753766811902755, -0.6180339887498947 -1.9021130325903073, 0.9079809994790935 -1.7820130483767358, -1.175570504584946 1.618033988749895, -1.414213562373095 -1.4142135623730951, 1.6180339887498947 -1.1755705045849465, -1.7820130483767356 0.9079809994790937, -1.902113032590307 -0.618033988749895, 1.9753766811902753 -0.312868930080462, -2 -0.0000000000000002, 1.9753766811902755 0.3128689300804615, -1.9021130325903073
0.6180339887498946, -1.7820130483767358 0.9079809994790934, 1.618033988749895 1.175570504584946, -1.4142135623730954
1.414213562373095, -1.1755705045849465 1.6180339887498947, 0.9079809994790938 1.7820130483767356, -0.6180339887498951
1.902113032590307, -0.3128689300804621 1.9753766811902753, 0.0000000000000004 2, 0.3128689300804614 1.9753766811902755,
0.6180339887498945 1.9021130325903073, 0.9079809994790933
1.782013048376736, 1.1755705045849458 1.6180339887498951,
1.4142135623730947 1.4142135623730954, 1.6180339887498947
1.1755705045849467, 1.7820130483767356 0.9079809994790939,
1.902113032590307 0.6180339887498952, 1.9753766811902753
0.3128689300804622, 2 0))
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Crop Coverage
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Bounds
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Vector Clip and Ship
Thanks to Andrea Aime @
GeoSolutions for this one
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Even Better: Chain processes
Buffer
Clip
Union
Reproject
Contour
Import
Etc…
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What processes?
• JTS Topology Suite
– Buffer, centroid, contains, touches, etc.
• Internal GeoTools/GeoServer processes
– Bounds, Clip, Snap, Import, Query, Reproject, etc.
• And user defined…
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Build yer own damn process
•
•
•
•
Extensible architecture
WPS doesn’t even have to be spatial
WPS is a framework
So…
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Option 1: Be a Java dev
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Option 2: GeoScript(.org)
• Use your own familiar scripting language
• JavaScript! Python! Scala! Groovy!
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Real World Ideas
• Hydrography: Draw water features on a map
that need to conform to rules (a stream can’t
cross a lake)
• Forestry: submit an area to find out its average
slope, aspect and elevation, to determine ease
of cutting/replanting trees.
• Cell service: compute viewshed analysis of cell
towers (to determine coverage)
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The real benefit to using WPS
• Big data
• Big processing
• Small input/outputs
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More Real World Usage
Norwegian Mapping Agency: Draw a line on
a map and generate an elevation profile
http://norgeskart.no/adaptive2/default.aspx?gui=1&lang=1
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Rendering Transformations
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Rendering Transformations
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Future
• Better client-side apps that utilize server
processes
• Improved method of defining processes
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Thanks!
mike@opengeo.org
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