Scripting GeoServer with GeoScript Groovy

1. Scripting GeoServer
Jared Erickson
CUGOS
December 2012

2. GEOSERVER
Open Source (GPL) WMS Server
Main language is Java
Also implements WFS, WCS, WPS, ect...
Uses GeoTools and JTS libraries

3. Scripting Module
Geoserver Community Module
Developed by: Justin Deoliveira and Tim
Schaub
I am adding Geoscript Groovy support
https://github.com/jericks/geoserver/tree/script_groovy
Python, JavaScript, Groovy, BeanShell, Ruby
Uses javax.scripting to execute scripts
Extend GeoServer on the fly

4. Scripting Hooks
Applications
Web Processing Services (WPS)
Geospatial web services
Rendering Transformations in SLD
Filter Functions
String, Date, Geometry Functions in SLD

5. Script Location
$DATA_DIR/scripts/
apps
function
wps
lib
Scripts dynamically reloaded
Python, JavaScript, and Groovy have
GeoScript API

6. Applications
Generic web applications or web services
Python - WSGI
JavaScript - JSGI
Groovy - Restlet

7. Hello World App
1 import org.restlet.data.*
2
3 def run(request, response) {
4 response.setEntity("Groovy rocks!", MediaType.TEXT_PLAIN)
5 }
$DATA_DIR/scripts/apps/hello/main.groovy

8. Color Brewer App
1 import org.restlet.data.*
2 import org.restlet.resource.OutputRepresentation
3 import javax.imageio.ImageIO
4 import geoscript.filter.Color
5 import groovy.xml.MarkupBuilder
6
7 def run(request, response) {
8 String name = request.getResourceRef().getQueryAsForm().getFirstValue("name")
9 if (name) {
10 def image = Color.drawToImage(Color.getPaletteColors(name))
11 def output = new OutputRepresentation(MediaType.IMAGE_PNG) {
12 void write(OutputStream out) throws IOException {
13 ImageIO.write(image,"png",out)
14 }
15 }
16 response.setEntity(output)
17 }
18 else {
19 def out = new StringWriter()
20 def html = new MarkupBuilder(out)
21 html.html {
22 head {
23 title: "Color Brewer Palettes"
24 }
25 body {
26 h1 "Color Brewer Palettes"
27 ul {
28 Color.paletteNames.each { nm ->
29 li {
30 a href: "colorbrewer?name=${nm}", "${nm}"
31 }
32 }
33 }
34 }
35 }
36 response.setEntity(out.toString(), MediaType.TEXT_HTML)
37 }
38 }
$DATA_DIR/scripts/apps/colorbrewer/main.groovy

9. Color Brewer App

10. Function List app
1 import org.restlet.data.*
2 import geoscript.filter.Function
3 import groovy.xml.MarkupBuilder
4
5 def run(request, response) {
6 def out = new StringWriter()
7 def html = new MarkupBuilder(out)
8 html.html {
9 head {
10 titie: "Filter Functions"
11 }
12 body {
13 h1 "Filter Function"
14 ul {
15 Function.functionNames.each { nm ->
16 li "${nm}"
17 }
18 }
19 }
20 }
21 response.setEntity(out.toString(), MediaType.TEXT_HTML)
22
23 }
$DATA_DIR/scripts/apps/functions/main.groovy

11. Function List app

12. Groovy Geoserver API
geoserver
Geoserver: Main entry point for Catalog and Config
Config: Metadata about GeoServer
geoserver.catalog
Catalog: Contains Workspaces, Layers, Stores
Workspace: Contains Stores
Store: Contains Layers, Converts to GeoScript Workspace
Layer: Converts to GeoScript Layer

13. layer as table app
1 import org.restlet.data.*
2 import geoserver.*
3 import groovy.xml.MarkupBuilder
4
5 def run(request, response) {
6
7 def layer = new GeoServer().catalog.getLayer("sf:archsites")
8 def gsLayer = layer.geoScriptLayer
9
10 def out = new StringWriter()
11 def html = new MarkupBuilder(out)
12 html.html {
13 head {
14 title: "Layer Table"
15 }
16 body {
17 h1 "${layer.name}"
18 table(border:1) {
19 tr {
20 gsLayer.schema.fields.each {fld ->
21 td "${fld.name}"
22 }
23 }
24 gsLayer.eachFeature { f ->
25 tr {
26 f.attributes.each { att ->
27 td "${att.value}"
28 }
29 }
30 }
31 }
32 }
33 }
34 response.setEntity(out.toString(), MediaType.TEXT_HTML)
35 }
$DATA_DIR/scripts/apps/table/main.groovy

14. Layer as table app

15. Filter Functions
Transform a value before displaying it
Format a date or a number
Capitalize a string
Manipulate a geometry
GeoTools input objects are wrapped as
GeoScript objects
GeoScript result objects are unwrapped as
GeoTools objects

16. Filter Function
1 /**
2 * Convert a Geometry into a buffered centroid
3 * @param value The Feature
4 * @param args A List of arguments
5 * args[0] is the Geometry
6 * args[1] is the buffer distance
7 */
8 def run(value, args) {
9 args[0].centroid.buffer(args[1] as double)
10 }
$DATA_DIR/scripts/function/bufferCentroid.groovy

17. Geometry filter function
1 <?xml version="1.0" encoding="ISO-8859-1"?>
2 <StyledLayerDescriptor version="1.0.0"
3 xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd"
4 xmlns="http://www.opengis.net/sld" xmlns:ogc="http://www.opengis.net/ogc"
5 xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
6 <NamedLayer>
7 <Name>Buffered Centroid</Name>
8 <UserStyle>
9 <Title>Buffered Centroids Polygons</Title>
10 <Abstract>Draw buffered centroids of polygons</Abstract>
11 <FeatureTypeStyle>
12 <Rule>
13 <Name>Rule 1</Name>
14 <Title>Gray Polygon with Black Outline</Title>
15 <Abstract>A polygon with a gray fill and a 1 pixel black outline</Abstract>
16 <PolygonSymbolizer>
17 <Geometry>
18 <ogc:Function name="bufferCentroid">
19 <ogc:PropertyName>the_geom</ogc:PropertyName>
20 <ogc:Literal>1</ogc:Literal>
21 </ogc:Function>
22 </Geometry>
23 <Fill>
24 <CssParameter name="fill">#AAAAAA</CssParameter>
25 </Fill>
26 <Stroke>
27 <CssParameter name="stroke">#000000</CssParameter>
28 <CssParameter name="stroke-width">1</CssParameter>
29 </Stroke>
30 </PolygonSymbolizer>
31 </Rule>
32 </FeatureTypeStyle>
33 </UserStyle>
34 </NamedLayer>
35 </StyledLayerDescriptor>

18. Geometry Filter Function

19. WPS
Web Processing Service
Model builder for the web
Generic web services for spatial data
GeoTools inputs are wrapped as GeoScript
objects
GeoScript results are unwrapped as GeoTools
objects

20. Geometry Buffer WPS
1 import geoscript.geom.Geometry
2
3 title = 'Buffer'
4 description = 'Buffers a geometry'
5
6 inputs = [
7 geom: [name: 'geom', title: 'The geometry to buffer', type: Geometry.class],
8 distance: [name: 'distance', title: 'The buffer distance', type: Double.class]
9 ]
10
11 outputs = [
12 result: [name: 'result', title: 'The buffered geometry', type: Geometry.class]
13 ]
14
15 def run(input) {
16 [result: input.geom.buffer(input.distance as double)]
17 }
18
$DATA_DIR/scripts/wps/buffer.groovy

21. WPS REQUEST BUILDER

22. Buffer geometry WPS
POLYGON ((11 1, 10.807852804032304 -0.9509032201612824, 10.238795325112868 -2.826834323650898, 9.314696123025453 -4.555702330196022, 8.071067811865476
-6.071067811865475, 6.555702330196023 -7.314696123025453, 4.826834323650898 -8.238795325112868, 2.9509032201612833 -8.807852804032304, 1.0000000000000007 -9,
-0.9509032201612819 -8.807852804032304, -2.826834323650897 -8.238795325112868, -4.55570233019602 -7.314696123025453, -6.071067811865475 -6.0710678118654755,
-7.314696123025453 -4.555702330196022, -8.238795325112868 -2.8268343236508944, -8.807852804032306 -0.9509032201612773, -9 1.0000000000000075,
-8.807852804032303 2.950903220161292, -8.238795325112862 4.826834323650909, -7.3146961230254455 6.555702330196034, -6.071067811865463 8.071067811865486,
-4.555702330196008 9.314696123025463, -2.826834323650879 10.238795325112875, -0.9509032201612606 10.807852804032308, 1.0000000000000249 11,
2.950903220161309 10.807852804032299, 4.826834323650925 10.238795325112857, 6.555702330196048 9.314696123025435, 8.071067811865499 8.07106781186545,
9.314696123025472 6.555702330195993, 10.238795325112882 4.826834323650862, 10.807852804032311 2.9509032201612437, 11 1))
http://localhost:8080/geoserver/wps?service=WPS
&version=1.0.0
&request=Execute
&identifier=groovy:buffer
&datainputs=geom=POINT%20(1%201)
@mimetype=application/wkt;distance=10
&RawDataOutput=result=@mimetype=application/wkt

23. Voronoi Layer WPS
1 import geoscript.geom.*
2 import geoscript.layer.*
3
4 title = 'VoronoiLayer'
5 description = 'Create a voronoi diagram around the features of a Layer'
6
7 inputs = [
8 layer: [name: 'layer', title: 'The Layer', type: Layer.class],
9 ]
10
11 outputs = [
12 result: [name: 'result', title: 'The voronoi diagram as a Layer', type: Layer.class]
13 ]
14
15 def run(input) {
16 def geoms = new GeometryCollection(input.layer.features*.geom.centroid)
17 def output = new Layer()
18 output.add([geoms.voronoiDiagram])
19 [result: output]
20 }
21
$DATA_DIR/scripts/wps/voronoi.groovy

24. WPS Request Builder

25. Rendering transformations
Modify an entire dataset
Buffer the entire layer not each feature
Create a heatmap from points (vector to raster)
http://docs.geoserver.org/latest/en/user/
styling/sld-extensions/rendering-
transform.html

26. Rendering Transform sld
1 <?xml version="1.0" encoding="ISO-8859-1"?>
2 <StyledLayerDescriptor version="1.0.0"
3 xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd"
4 xmlns="http://www.opengis.net/sld"
5 xmlns:ogc="http://www.opengis.net/ogc"
6 xmlns:xlink="http://www.w3.org/1999/xlink"
7 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
8 <!-- a Named Layer is the basic building block of an SLD document -->
9 <NamedLayer>
10 <Name>default_polygon</Name>
11 <UserStyle>
12 <!-- Styles can have names, titles and abstracts -->
13 <Title>Default Polygon</Title>
14 <Abstract>A sample style that draws a polygon</Abstract>
15 <!-- FeatureTypeStyles describe how to render different features -->
16 <!-- A FeatureTypeStyle for rendering polygons -->
17 <FeatureTypeStyle>
18 <Transformation>
19 <ogc:Function name="groovy:voronoi">
20 <ogc:Function name="parameter">
21 <ogc:Literal>layer</ogc:Literal>
22 </ogc:Function>
23 </ogc:Function>
24 </Transformation>
25 <Rule>
26 <Name>rule1</Name>
27 <Title>Gray Polygon with Black Outline</Title>
28 <Abstract>A polygon with a gray fill and a 1 pixel black outline</Abstract>
29 <PolygonSymbolizer>
30 <Fill>
31 <CssParameter name="fill">#AAAAAA</CssParameter>
32 </Fill>
33 <Stroke>
34 <CssParameter name="stroke">#000000</CssParameter>
35 <CssParameter name="stroke-width">1</CssParameter>
36 </Stroke>
37 </PolygonSymbolizer>
38 </Rule>
39 </FeatureTypeStyle>
40 </UserStyle>
41 </NamedLayer>
42 </StyledLayerDescriptor>
43

27. Voronoi Diagram

28. Conclusion
GeoServer is well known as a WMS, WFS,
WCS, WPS server
GeoServer is also a platform for spatial web
services
Scripting just finally makes it easy

29. Thank you!