Web Processing Service:The Final Frontier For Web GIS

Mike Pumphrey

April 25, 2012

• Serve data to anyone with a Net connection

• Create pretty/informative interactive maps

• Integrate maps and software/interfaces

Web Mapping is cool

2

Q: So why does anyone still use Desktop GIS software?

3

“It looks nice, but can I determine viewsheds?”

A: Web Mapping != GIS

4

The End

5

The End

6

• Distribution of time

• Distribution of energy

• Distribution of content

Benefits of web-based anything

7

• Web Map Service (WMS)

• Web Feature Service (WFS)

• Web Coverage Service (WCS)

OGC services (review)

8

Introducing:Web Processing Service

9

“[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.”

WPS Definition:

10

You can do analysis over the web.

(Cool!)

Translation:

11

• Processes exist on a server

• Request comes from client

• Server executes and outputs

How Does It Work

12

• GetCapabilities (GetCapabilities)

• DescribeProcess (DescribeFeatureType)

• ExecuteProcess (GetFeature)

Just Like Other OGC Services

13

• Can be POSTed (ugh)

• Can be stored on the server (yay!)

What About Data?

14

• 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 andsave on the server

Data on server = interesting!

15

• Available as a GeoServer community extension

• Alternately, core component in OpenGeo Suite

GeoServer has WPS support

16

GeoServer: GUI interface for WPS

17

Unavoidable example:Point Buffer

18

19

20

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))

Crop Coverage

21

Bounds

22

Vector Clip and Ship

23

Thanks to Andrea Aime @ GeoSolutions for this one

Even Better: Chain processes

24

BufferBuffer UnionUnion

ClipClip ContourContourReprojectReproject ImportImport

Etc…

• JTS Topology Suite– Buffer, centroid, contains, touches, etc.

• Internal GeoTools/GeoServer processes– Bounds, Clip, Snap, Import, Query, Reproject, etc.

• And user defined…

What processes?

25

• Extensible architecture

• WPS doesn’t even have to be spatial

• WPS is a framework

• So…

Build yer own damn process

26

Option 1: Be a Java dev

27

• Use your own familiar scripting language

• JavaScript! Python! Scala! Groovy!

Option 2: GeoScript(.org)

28

• 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)

Real World Ideas

29

• Big data

• Big processing

• Small input/outputs

The real benefit to using WPS

30

Norwegian Mapping Agency: Draw a line on a map and generate an elevation profile

http://norgeskart.no/adaptive2/default.aspx?gui=1&lang=1

More Real World Usage

31

32

Rendering Transformations

33

Rendering Transformations

34

• Better client-side apps that utilize server processes

• Improved method of defining processes

Future

35

Thanks!

36

mike@opengeo.org