1. GIS on the Web; web sources of GIS data

2. Web Mapping Defined Web servers and map viewer clients interact to -
Parcels
Roads
Images
Boundaries
...
Catalog View
Whoville
Cedar Lake
Integrated View
Discover, access and retrieve views from multiple servers
Display multiple layers of geographic data within a single web application
Internet
Query and update
Framework
(Clearinghouse)
Environment
Crime
Social
Services
Land
Parcel
Federal
Program
Weather
Provide interface for visualization, Decision Support, etc.
Here is the Web Mapping vision again, this time with the requirements for WMT I highlighted in blue.
Support geocoded raster, vector, matrix, and other data

3. How can I combine data from each of these
Mapping on the Web
Today
Here is an example of how the Web Mapping today can be significantly improved by the efforts of Open GIS to develop Web Mapping interoperability standards.
A business owner in the U.S. can gain access to local community and federal government web mapping sites to obtainmportant environmental, housing, economic information about a community in New York State.
Upon closer inspection, all three sites of the web sites have some similar information (roads for example), and all three sites have information unique to that site.
Although, I can review each of these sites separately, I cannot put all the information together in a single application. So, these tools, while helpful, do not provide me with the additional capability to integrate the desired data into a single view.
Each of these web sites obtains and integrates data from outside sources so that they can provide an integrated view of the area and the information they are responsible for maintaining. This results in the same data being maintained many time. Web mapping standards would allow data from outside sources to be accessed and integrated when needed.
How can I combine data from each of these
sources to answer my question?

4. Viewers: Web Services for Generating SVG Tiny Maps on Mobile Phones
Java + Batik
Torque-GIS Demo
Services for generating object textures for Torque
J2ME device
.Net + C#
Viewers:
TinyLine
Squiggle
Adobe’s ASV

5. Metadata Needed to automate the process of search for data
compare using a library catalog
Needed to determine the fitness of a data set for use
particularly regarding quality
Needed to handle data effectively
e.g., format
Needed to identify notable data contents
e.g., to find images of an interesting hurricane

6. Metadata can be Expensive to Generate
They represent a high level of abstraction
and may need an expert to define
But the benefits are substantial
metadata make it possible to find data sets, and use them effectively
they allow the benefits of investments in data to be realized

7. The U.S. FGDC Standard
Content Standards for Digital Geospatial Metadata (CSDGM)
Defined by a committee of U.S. Federal agencies
Now widely used worldwide
The basis of a new international standard
Potentially several hundred items for one data set
but easily boiled down to a much smaller number

8. The Dublin Core Standard
Devised by the digital library community
Suitable for any type of data, geospatial included
easily extended to include essential items for geospatial data
e.g., the latitude and longitude limits of the data set’s coverage

9. Online

10. The data portal

11. Interactive access to HIS digital library
Hydroviewer
CuahsiLink
REST/SOAP APIs
Metadata (mif, mtf)
SRB (ADOs)

12. Application services: analysis, mapping, charting, models,
Service consumers
NWIS
Matlab
ArcGIS
Fortran/C/VB/Java codes
Excel
Web browser
portal
User registration/authentication/authorization (9)
Application services: analysis,
mapping, charting, models,
workflow, integration (8) W e b s r v i c g t y a n d l ( 1 )
ArcGIS R
Conversion
Certificate
Server
Server
engine
authority
Data registration/Search/
Query rewriting & orchestration.(6)
Ontology
source and
services (7)
DL services
layer
(5)
External data resources registry
DL metadata
Resource drivers (2)
Digital Library
NAWQA
STORET
. . .
Sensor data filtering (4)
Sensor management services (3)
Core grid services: monitoring nodes, scheduling,
data transfer, replication, collection
management,…(1)
Sensors
Sensors
Sensors
Sensors
PoP Node
PoP Node
PoP Node
PoP Node

13. USGS: National Mapping

14. US GeoData ftp access to DEM DLG GNIS GIRAS etc.

15. NOAA: Weather and other data

16. Why build an SDI?
Build data once and use it many times for many applications
Integrate distributed providers of data: Cooperative governance
“Place-based management”
Share costs of data creation and maintenance
Support sustainable economic, social, and environmental development

17. Types of geospatial standards
Data Classification
e.g., Vegetation Classification
Data Content
e.g., Digital Geospatial Metadata, Spatial Schema
Data Symbology or Presentation
e.g., Digital Geologic Map Symbolization
Data Transfer
Data Services (Web Mapping, Feature)
Data Usability
e.g., Geospatial Positioning Accuracy

18. What is the OpenGIS? Open Geospatial Consortium (OGC)
Non-profit, international voluntary consensus standards organization
Industry, government, and university members
Over 260 members worldwide – 30 countries & 5 continents
91 European members - 19 countries
35 Asia-Pacific members - Japan, Republic of Korea, Australia, China, and Thailand
OGC collaborates and works closely with:
International Organization for Standardization (ISO)
World Wide Web Consortium (W3C)
OASIS
And others…

19. OGC Membership Levels OGC members participate at four levels:
Associate: Commercial and university members granted non-voting participation in Technical Committee, and full access to OGC technical documents.
Technical: participate and vote in OGC Technical Committee, creating the OpenGIS® Specifications in Special Interest and Working Groups.
Principal: participate and vote in OGC Technical and Planning Committees, providing management of OGC Specification Program and Interoperability Program and guides OGC Technology Roadmap and Interface Development Schedule.
Strategic: highest level of OGC membership, voting in both the OGC Technical Committee and the OGC Planning Committee and receive additional benefits from the Consortium based on a specific business plan jointly developed with OGC.

20. Approved Specifications
Simple Feature Access – OLE, SQL, CORBA
Catalog 1.1.1
Coordinate Transformation 1.1
Grid Coverages 1.0
Web Map Service (2.0 in final edit) (WMS)
Geography Markup Language 3.0 (GML) pages alone!!!
Web Feature Service 1.0
Filter 1.0
Style Layer Descriptor 1.0 (SLD)
Web Coverage Service 0.0 (WCS)
OpenLS
OGC Web Services (Ongoing)
Web Map Client Configuration

21. WMS: Web Map Service Mature, well-established specification
Version 1.0 issued
Version issued
Server & client support in many vendor products & freeware
Scope: geographic data rendered as images ("maps"), not actual data values
Similar to ArcIMS Image Server
Demo: see lifemapper.org or
Western Australia:

22. OGC Web Map Service Interfaces
GetCapabilites
GetMap
GetFeatureInfo

23. WMS - getCapabilties allows the server to advertise what it can do:
available layers
supported output projections
supported output formats
scale hints
extent of data
XML format

24. WMS - getMap allows the retrieval of a map from a web server
user supplies bounding box, image size, format, error handling, etc…
server responds with an “image”, typically a web-ready format like GIF, PNG or TIFF

25. GetMap Request Example
REQUEST=GetMap&
SRS=EPSG:4326&
BBOX= ,24.913,78.794,36.358&
WIDTH=560&
HEIGHT=350&
LAYERS=BUILTUPA,COASTL,POLBNDL&
STYLES=0XFF8080,0X101040,BLACK&
FORMAT=image/png&
BGCOLOR=0xFFFFFF&
TRANSPARENT=TRUE&

26. WMS – getFeatureInfo allows the retrieval of simple feature attributes
user supplies an x,y coordinate pair and a layer of interest
server responds with attribute information in HTML, GML or arbitrary ASCII format
… optional interface

27. WMS Limitations all you get is a picture, not the data
limited control over how the data is “styled”
particularly limiting with regards to labeling
supports only a small portion of functionality typically supported by a vendor

28. Style Layer Descriptor enabled Web Map Service
In a basic WMS style is “just a name” that identifies a specific layer portrayal
An SLD WMS adds the ability to control layer style
An SLD WMS adds the following additional operations that are not available on a basic WMS:
DescribeLayer
GetLegendGraphic
GetStyles
PutStyles
These interfaces are described in the SLD specification document

29. WFS: Web Feature Service
WFS 1.0 approved 2002
ISO has requested it be submitted
Scope: storage & retrieval of geographic vector feature data (point/line/polygon)
Hydrography, Transportation, Government Units, Cadastral, Geodetic Control
Similar to ArcIMS Feature Server

30. OGC Web Feature Server Interfaces
OGC WFS Interfaces
GetCapabilites
DescribeFeatureType
GetFeature
Transaction
LockFeature/GetFeatureWithLock
Response to GetFeature request is formatted using GML (typically)

31. Two classes of WFS Basic WFS
A basic WFS would implement the GetCapabilities, DescribeFeatureType and GetFeature operations. This would be considered a READ-ONLY web feature service.
Transaction WFS
A transaction web feature service would support all the operations of a basic web feature service and in addition it would implement the Transaction operation. Optionally, a transaction WFS could implement the LockFeature operation.

32. Basic WFS GetCapabilities
A web feature service must be able to describe its capabilities. Specifically, it must indicate which feature types it can service and what operations are supported on each feature type.
DescribeFeatureType
A web feature service must be able, upon request, to describe the structure of any feature type it can service.
GetFeature
A web feature service must be able to service a request to retrieve feature instances..

33. Transaction WFS Transaction
A web feature service may be able to service transaction requests. A transaction request is composed of operations that modify features; that is create, update, and delete operations on geographic features.
LockFeature/GetFeatureWithLock
A web feature service may be able to process a lock request on one or more instances of a feature type for the duration of a transaction.

34. DescribeFeatureType
Generates a schema definition for the requested features using the language specified in the capabilities document (XML schema is mandatory, others are optional)
The XML schema document must be a valid GML application schema and defines the schema of the feature types listed in the request.
Feature geometry must be expressed using the GML geometry description.
Spatial Reference Systems must be consistent with GML

35. GetFeature
The GetFeature operation allows retrieval of features from a web feature service.
The request contains queries which may unconstrained or constrained by a Filter
Filter is described in described in the Filter Encoding Specification
The output format is GML by default but the specification allows other formats

36. Basics of GML
Geography Markup Language (GML) is an XML grammar written in XML Schema for the modeling, transport, and storage of geographic information.
GML provides a variety of kinds of objects for describing geography including features, coordinate reference systems, geometry, topology, time, units of measure and generalized values.
GML includes
Geometries and Coordinate Reference System (based on EPSG)
A temporal reference system (based on ISO 8601)
A Units of Measure (UOM) dictionary

37. GML 3.0
GML models various resources required to describe geospatial information:
Features (including coverages and observations).
Coordinate Reference Systems
Units of Measure
Values (as values of feature properties)
Topology and Geometry (as values of feature properties)
Temporal (as values of feature properties)

38. The Three Architecture Cases
The Graphic Element Case
The Data Case
The Picture Case
(source: OpenGIS document )

39. Architectures for Different Applications
Each map request sends new geometry:
Examples: find by address or another attribute; routing, “single-attribute” maps, weather maps, etc.
In general: situations when geometry is defined by attribute (categorical coverages, for example)
Geometry remains relatively constant:
Examples: atlases, statistical maps for collection zones (states, counties, census tracts)
In general: situations with many attributes for limited number of geometries
For the latter case: makes sense to cache and re-use coordinate information on the client side as much as possible. For each application, there is some right mix of the two approaches.

40. From Geography Markup to Rendering
<?xml version="1.0" encoding="iso "?>
<rs>
<r><name>Horton Plaza</name><URL></URL><labelpos>41.46,77.51</labelpos><c>5076, , , , , , , , , , , , , , , , , ,1646 </c></r>
<r><name>Gaslamp</name><URL></URL><labelpos>44.60,83.00</labelpos><c>5162, , , , , , , , , , , , , , , , , , ,1013 </c></r>
. . .
<?xml version="1.0"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG Stylable//EN" " [
<!ENTITY base "fill:#ff0000;stroke:#000000;stroke-width:1;">
]>
<svg width="100%" height="100%" viewBox=" " style="shape-rendering:geometricPrecision; text-rendering:optimizeLegibility">
<g id="karta" transform="scale(1, -1) translate(0, -7547)">
<g id="base" style="&base;">
<path id="a1" title="Horton Plaza" style="fill:#00ff00;" d="M5076,1540L 4986, , , , , , , , , , , , , , , , , ,1540z"/>
<path id="a2" title="Gaslamp" style="fill:#ffff00;" d="M5162,1013L 5084, , , , , , , , , , , , , , , , , , ,1013z"/>
</g></g></svg>
Or SVG
SVG
<html xmlns:v="urn:schemas-microsoft-com:vml"><head><style>v\:* { behavior: url(#default#VML); }</style>
. . .
<v:shape id="a1" class=z style="left:0;top:0;width:11590;height:7547" fillcolor="#FFFF99" strokecolor="#000000" strokeweight="1" title="Horton Plaza" path="m5076,1540l 4986, , , , , , , , , , , , , , , , ,1646xe"/><v:shape id="a2" class=z style="left:0;top:0;width:11590;height:7547" fillcolor="#FFFF99" strokecolor="#000000" strokeweight="1" title="Gaslamp" path="m5162,1013l 5084, , , , , , , , , , , , , , , , , ,1013xe"/>
<div class=label style="top:75.51%; left:39.46%;">Horton Plaza</div><div class=label style="top:81%; left:42.6%;">Gaslamp</div>
Rendering markup (such as VML)
VML
XML encoding of geographic features (such as GML)

41. Map Structure Map Structure
<svg id="axiomap" onload="initMap(evt)" onmousemove="GetElementAndPosition(evt)" onmousedown="set_menu()" >
<rect id="canvas" fill="white" stroke-width="0" x="0" y="0" width="100%" height="100%"/>
<desc></desc>
<defs>
<menu id="MENU" xmlns="
<header>Custom Menu</header>
. . .
</menu>
</defs>
  <g id="map" style="stroke-linejoin:round; stroke-linecap:round">
<g id="background_polygons"/>
<g id="base_thematic"/>
<g id="foreground_polygons "/>
<g id="optional_polygons "/>
<g id="foreground_lines"/>
<g id="optional_lines"/>
<g id="foreground_points"/>
<g id="optional_points"/>
<g id="cosmetic"/>
<g id="tooltips" style="shape-rendering:optimizeSpeed">
. . . </g>
<g id="stable_gui_elements“ style="shape-rendering:optimizeSpeed">
<g id="map_title" style="visibility:visible">
. . . </g>
<g id="layer_navigation_group">
<g id="legend" style="visibility:hidden" . . .>
</g>
<g id="extras"></g>
</svg>
Map Structure

42. Geography Network
The Geography Network is a global community of data providers who are committed to making geographic content available.
This content is published from many sites around the world, providing you immediate access to the latest maps, data, and related services.

43. Geography network View Live Maps Download Geodata
Build Custom Applications     
Publish Your Content
Find Useful Tools     
Share Your Ideas

44. Geography Network and ArcIMS Lab