NLWIS Architecture

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NLWIS Architecture

• Alberta GeoConnections/NLWIS presentation
• April 19, 2006
• Peter Schut

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Agenda

• Scope and Principles of N-GIS
• Development Approach and Architecture
• CGDI Standards Implementation

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Scope and Principles
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Scope of N-GIS

• Supports development of geospatial information
  and NLWIS services
• Deliver, via the Internet
• Data
• Information
• Knowledge
• Interpretations
• without human intervention

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Context

• N-GIS is evolutionary
• It is a further development of
• CanSIS (1972)
• PFRA GIS (1991)
• and an implementation of the CGDI
• N-GIS will provide timely and relevant
  agri-environmental geospatial information
• N-GIS will provide the capacity to search,
  collect, maintain, interpret and deliver land
  management to support decision making
• N-GIS will adopt the latest standards and
  technologies from CGDI to deliver existing GIS
  capabilities more efficiently
• CanSIS Canadian Soil Information System
• PFRA Prairie Farm Rehabilitation
  Administration
• GIS Geographic Information System
• CGDI Canadian Geospatial Data Infrastructure

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Links to Programs and Systems External to AAFC
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N-GIS supports Business Components
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Development Principles - 1

• Geoconnections principles and GOL
• Data should be collected once and used many times
• Data should be managed closest to source
• i.e., soils data should be managed by AAFC
• Data housed on individual specialized systems
  owned by various agencies is shared, in order to
  reduce duplication of collection and storage
• N-GIS will use the same standard interfaces as
  other major federal initiatives (NFIS, CISE,
  MGDI)
• GOL Government On Line

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Development Principles - 2

• Component-based system, built on standards-based
  interface specifications (Geoconnections OGC,
  ISO, W3C)
• Web Map Service (WMS)
• Web Feature Service (WFS)
• Web Coverage Service (WCS)
• Web Processing Service (WPS)
• Geolinked Data Access Service (GDAS)
• Geolinking Service (GLS)
• Catalog (CAT)
• Develop collaboratively with partners
• SCOTS Standards-based Commercial Off The Shelf
• OGC Open Geospatial Consortium
• ISO International Organization for
  Standardization
• W3C World Wide Web Consortium
• GOL Government On Line

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Development Approach and Architecture
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N-GIS Physical Technology Overview
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N-GIS Technical Context
External Comunity
External Data Providers
Data Provider B OGC GIS Server
Data Provider C OGC GIS Server
AAFC OGC GIS Server
Intranet Internet
Data Conversion / Transformation
NLWIS Applications
WAN
AAFC
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N-GIS High Level End State Architecture
Web Browser UI
Data Management
CGDI Services
Web Applications
Data Access
Calculations
General Public
Data Marts
Data Warehouse
WPS
Generic Clients
Interpretations
Geolinking
Custom Clients
Calculations
Producers
GDAS
Discovery Tools
Models
Partners
WMS
WFS
OGDs
Direct Access by External Clients
Desktop
GIS
Remote Sensing
AAFC Staff Other Secure Users
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NLWIS Phasing Strategy Timelines
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N-GIS Web Services
Data Services
Calculation Services
Discovery Services

• WMS

• WPS

• CAT

• WFS

• WCS

User tools
Geolinking Services

• GDAS

• WGS

• LRV

web service client
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Web Services Development by Phase
Wrap some functionality as web services
Phase 2
Make additional web services
Phase 3
Make web services discoverable
Wrap web services with security
Phase 4
Facilitate web service chaining
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CGDI Standards Implementation
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Simple Web Mappingusing WMS and Context
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STEP 1 Create a WMS layer
GIS database
WMS
Ecoregion corn 1 2345 2 1030 3 3450
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STEP 2 Create a Web Map Context document
Web Map Context
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STEP 3 Present result to client
Web Map Context
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Going BeyondSimple Web Mapping
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business database
Requirement analyse data in a geospatial
context
Web Maps
GIS datasets
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business database
data access service (GDAS)
Step 1 make the data accessible via GDAS
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business database
data access service (GDAS)
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business database
data access service (GDAS)
Web Maps
geolinking service (GLS)
GIS datasets
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business database
data access service (GDAS)
analytical calculations (WPS)
Web Maps
geolinking service (GLS)
GIS datasets
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business database
data access service (GDAS)
analytical calculations (WPS)
Web Maps
geolinking service (GLS)
GIS datasets
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CGDI Standards Implementation
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GeoProcessing
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GeoProcessing

• Web Processing Service (WPS) is used to enable
  geographic operations over the Internet.
• Simple spatial operations
• Buffer
• Intersect
• Attribute manipulations
• Change in farming practices between census years
• Spatial Interpretations
• PARS
• Complicated modelling
• Soil erosion
• Climate change

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WMS, WFS, and Geo-Processing Scenario

• Scenario Objective
• Request a buffer around a selected feature from a
  layer on a remote server and return the
  resulting image with reference layers to the
  client.

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STEP 1 Select a Layer
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STEP 2 Select a Feature
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STEP 3 Define a buffer distance
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STEP 4 Results of the Buffer Feature
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GDAS and GeoLinking
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GDAS and GeoLinking

• Geolinked Data Access Service (GDAS) is used to
  deliver attribute data
• View in a browser
• Import into a spreadsheet
• Replicate data
• Geolink (Geodata store or WMS)
• GDAS facilitates data and application validation
  because the same output stream is used in each
  case.
• GeoLinking Service (GLS) is used to join
  attribute data to spatial features
• E.g. Census Data joined to Census Geography

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An example GDAS/GeoLinking API call is as
follows myString 'this.location.href"'.getd
ataHostName.'? SERVICEgdasVERSION0.9.2request
getdata DOMAIN'.domainName.'FRAMEWORK_VERSION
'.frameworkVersion.' FRAMEWORK'.frameworkName.
'DATASET'.datasetName.' ATTRIBUTES'.attribut
eName.'"' echo "ltscriptgt".myString."lt/scriptgt"

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GDAS Geo-Linking Scenario

• Scenario Objective
• Request a classified layer from a remote server
  with reference information

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STEP 1 Extract dataset using GDAS
Hectares of corn in 2001

• Extract a layer which describes the number of
  hectares of corn in 2001 using GDAS

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STEP 2 Create a WMS layer
Hectares of corn in 2001
WMS
Ecoregion hectares 1 2345 2 1030 3 3450
Geolinking Service
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STEP 3 Create a Web Map Context document
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STEP 4 Present result to client
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GDAS, GeoLinking, and GeoProcessing
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NAHARP Requirements

• MAPPING REQUIREMENTS
• 12,000 basic map layers from Census of
  Agriculture
• (flexibility)
• 30 indicators with hundreds of intermediate
  calculations
• (transparency)
• Total gt100,000 potential map layers
• SOLUTION
• (standards-based)
• Data stored in Oracle
• Client triggers map creation as follows
• Data retrieval via GDAS
• Processing via WPS
• Creation of a WMS layer using a Geolinking WMS
• Insertion of layer into a WMS client, using
  Context

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GDAS, Geolinking, and Geo-Processing Scenario

• Scenario Objective
• Request cornfield coverage data for two reference
  years and obtain the difference. Present the
  findings with reference layers in a merged WMS
  image.

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STEP 1 Extract 2 datasets using GDAS
GDAS
Hectares of corn in 2001
Hectares of corn in 1996
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STEP 2 Calculate difference using a WPS
Hectares of corn in 2001
change in corn 1996-2001
Web Processing Service
Hectares of corn in 1996
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STEP 3 Create a WMS layer
Geo-linking
change in corn 1996-2001
WMS
Ecoregion change 1 -10 2 2 3 3
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STEP 4 Create a Web Map Context document
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STEP 5 Present result to client
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