Geo script opengeo spring 2013

GeoScript
Ilya Rosenfeld | OpenGeo | Spring 2013

The Big Idea

A library for processing of spatial data

Several implementations for scripting environments

Currently in Python, Groovy, JavaScript, Scala, Ruby

GeoTools under the hood

Why GeoScript
Easy to learn

Simple to use

Familiar spatial metaphors

Choice of a scripting language

Versatile products

Evolving, free and open source

"Succinctness is Power."
- Paul Graham
Author or "Hackers and Painters"

Spatial Metaphors and API

Geometry Style
Feature Map
Workspace Projection
Filter Function
Layer Process

http://www. geoscript.org

Load, style and display data ...
# import libraries
from geoscript.layer import Shapefile
from geoscript.render import draw
from geoscript.style import *

# load data
solar = Shapefile("solar_dni_polygons_fla.shp")

# style and display it
solar.style = Stroke("blue")
draw(solar)

Examine data ...
# show structure of the data
solar.schema

# print out a single attribute for each record
for f in states.features():
print f["STATE"]

# aggregate all values of "DEC" attribute
list = [f.get("DEC") for f in solar.features()]
reduce(lambda a,b: a+b, list)

... output
shapefile's schema:
solar_dni_polygons_fla [the_geom: MultiPolygon, ID: long,
GRIDCODE: float, ANN_DNI: float, JAN: float, FEB: float, MAR:
float, APR: float, MAY: float, JUN: float, JUL: float, AUG: float,
SEP: float, OCT: float, NOV: float, DEC: float]

"DEC" attribute values:
[4.268077957, 4.268077957, 4.268077957, 4.268077957...

aggregate value of "DEC":
6791.922061828683

Build a Histogram ...
# import
from geoscript.plot import bar

# populate data for X axis
x = [1,2,3,4,5,6,7,8,9,10]

# populate data for Y axis
y = [i * i for i in x]

# draw histogram
bar.xy(zip(x,y)).show()

GeoScript Processes
AddCoverages, AreaGrid, Contour, CropCoverage, MultiplyCoverages,
PolygonExtraction, RangeLookup, RasterAsPointCollection, RasterZonalStatistics,
ScaleCoverage, StyleCoverage, length, isEmpty, contains, disjoint, intersects,
isClosed, isValid, buffer, getY, getX, union, intersection, difference, distance,
envelope, dimension, overlaps, reproject, simplify, isSimple, equalsExact,
getGeometryN, isWithinDistance, touches, crosses, within, relate, convexHull,
symDifference, centroid, interiorPoint, numPoints, area, isRing, exteriorRing,
numInteriorRing, numGeometries, geometryType, boundary, relatePattern,
equalsExactTolerance, pointN, startPoint, endPoint, interiorRingN, densify,
polygonize, splitPolygon, Aggregate, BarnesSurface, Bounds,
BufferFeatureCollection, Centroid, Clip, CollectGeometries, Count, Feature, Grid,
Heatmap, InclusionFeatureCollection, IntersectionFeatureCollection, LRSGeocode,
LRSMeasure, LRSSegment, Nearest, PointBuffers, PointStacker, Query,
RectangularClip, Reproject, Simplify, Snap, Transform, UnionFeatureCollection,
Unique, VectorToRaster, VectorZonalStatistics, ...

+ WRITE YOUR OWN

Run a process ...
# import
from geoscript.process import Process

# bind to a process and examine its inputs
p = Process.lookup("vec:Centroid")
p.inputs

# execute process
centroids = p.run(features=solar).get("result")

# draw result
draw(centroids)

>> Establishing Internet Connection ...

OGC WPS input output

In a nutshell:

● WPS: Web Processing Service
● web service interface standard
● standardizes metadata, inputs and outputs of a (spatial) process
● defines how a client can execute the process
● implementation: some processing algorithm

OGC WPS [HTTP] Operations:

● GetCapabilities: returns service metadata
● DescribeProcess: returns description of a process, its inputs and outputs
● Execute: returns output of a process

WPS How-to

Step 1: Hack GeoScript from command line.
Step 2: Wrap your code in a Process.
Step 3: Copy to GeoServer.

It lives, it runs!

WPS Example

origin

http://suite.opengeo.org/docs/processing/scripting/processcreate.html

Process Inputs and Outputs
vector
inputs
● GML outputs
● WKT ● WKT
● HTTP reference ● GML
● subprocess ● Shapefile ZIP
● feature collection ● ...
○ WFS collection
○ JSON
○ Shapefile ZIP
○ HTTP request
○ GeoServer VECTOR_LAYER
○ subprocess

outputs
raster ● TIFF
inputs ● ArcGrid
● TIFF ● ...
● ArcGrid
● HTTP reference
● GeoServer RASTER_LAYER
● subprocess

Pushing Ahead
GeoScript Rendering Transformations
● do processing from command line ● add advanced visualizations
● prototype and tweak your process ● author transformations using SLD
● use local and remote resources ● transform datasets in GeoServer

Process Chaining
● script complex processes
● wrap and deploy as a single service

Pushing Ahead
Web Mapping App Development Integration
● use OpenGeo Suite SDK ● invoke WPS from another system
● create a starter app automatically ● embed interactive maps into other apps
● customize, test and deploy

blog.opengeo.org
keyword: "solar"

Geo script opengeo spring 2013

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