free and open source web mapping

Free and Open Source Web Mapping

Prof. Maria Antonia Brovelli, Dr. Eng. Giorgio ZamboniPolitecnico di Milano – Como Campus – Italy

2Geospatial Web

Users

Catalogues

Data

Processes

INTERNET

3Web MappingWeb Map and Geodata

Servers Web Map and Geodata Clients

INTERNET

4Map mashing-upServers

Clients

INTERNET

5Interoperability / Standardization

• Open and interoperable components

• Interchangeable data

• De jure standard: technical instruction set by national and/or international standardization organizations (ISO/OGC/National standards)

• De facto standard: technical instruction used by a noteworthy number of people and/or organizations.

6OGC Web Service (OWS)

• XML (eXtensible Markup Language) is used for the definition and the description of applications. The communication is based (in the majority of cases) on the HTTP protocol. Because of using XML, Web Services are platform and OS-independent.

• The functioning of OWS (OGC Web Services) can be described in four steps:• the client contacts the server and queries it about its

functionalities• the server sends back to the client an XML document

containing the functionalities of the supported service• the client asks the server for data• the server provides the data as requested

7WMS Example

Client Server

getCapabilities

XML Service Metadata

getMap

Map

Map AMap BMap C

…

Map AMap BMap C

…

AB

C

Map B

8OGC Web Map and Geodata Services

• Data Delivery:• WMS: service that generates maps and

makes them available as images or as a series of graphical elements

• WFS: service that generates geographic entities or features. If the service is “transaction” (WFS-T), data manipulation is allowed

• WCS: service that generates geospatial coverages, that are geospatial information representing space-varying phenomena (fields)

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• Data formats:• SFS: Simple Feature Standard• GML: Geography Markup Language • KML: Keyhole Markup Language

• Data search:• CSW: Catalogue Service• WFS-G: Gazetteer Service

• Other:• WPS: Web Processing Service • CTS: Coordinate Transformation Service• WTS: Web Terrain Service • SLD: Styled Layer Descriptor • WMC: Web Map Context

OGC Web Map and Geodata Services

10FOSS Web Map - Geodata Servers (1)

Platform independent

Windows, Linux, Mac-OSX

Operating System:

JavaCLanguage:

WMS, WFS(-T), WCS, GML, KML, SLD

WMS, WFS(-T), WCS, GML, SLD, WMC

OGC:www.geoserver.orgwww.mapserver.orgWeb:GPLMITLicense:2001mid ‘90Birth:

11FOSS Web Map - Geodata Servers (2)

Platform independent

Windows, LinuxOperating System:

JavaC++Language:

WMS, WFS(-T), WCS, GML, CSW, WFS-G, WPS, WTS, SLD, WMC

WMS, WFSOGC:wiki.deegree.orgwww.mapguide.osgeo.orgWeb:LGPLLGPLLicense:20052004Birth:

12

• They are interactive viewers in the most of cases simply running in a web browser (Mozilla Firefox, Opera, Internet Explorer, etc.). Sometimes, depending on the technology adopted, plug-ins, i.e. pieces of software providing specific functionalities not available in the simple browser interaction, are requested.

• New generation web map and geodata clients are completely independent from the server application that lies behind them: they communicate indifferently by means of OGC open protocols with MapServer, GeoServer, MapGuide, deegree, etc.

• By means of this kind of applications, which renders maps from Web Map and Geodata Services, users can navigate maps, zoom in, zoom out, pan, click and query, turn layers on and off or add more maps. They can additionally edit map features (if data are served by a Transactional Web Feature Service), build their own maps, contacting different services on different machines and save them to be used at any time or to be shared.

Web Map and Geodata Clients (1)

1313

An example

Different languagesScalebar

Reference map

Legenda

Main map

Scale

1414

Zoom full extent

An example

BackZoom in/out

ForwardZoom to SelectedZoom inZoom outPan

IdentifySelectToolTipMeasureAdd Point of

InterestRefresh Map

1515

An example

WMS ServicesWFS ServicesData stored in the local server (e.g.: shapefiles, rasters, MapInfo tables and all the other formats supported by MapServer)

1616

An example

Searching tools:

Searchitem

Identify

Select

Tool Tip

:

17

Web mapping client

comparison(German Carrillo, 2010)

Web Map and Geodata Clients (2)

18

• Previous products are nicely presented for comparison in “Web mapping client comparison v.4” by German Carrillo (may 2010) (*)

• The comparison is divided in three parts:• general description: license, origin country, origin

company or entity, documentation (languages, formats, level [users, developers]), OSGeo support, comments;

• technical features: source code language, API language, OGC services supported, support of tile-based maps, need of proprietary plug-ins, inclusion of metadata component, mailing lists;

• links of interest: screenshot, current version, official website, documentation, features/roadmap, gallery/demo.

(*) http://geotux.tuxfamily.org/index.php?option=com_myblog&task=view&id=257&Itemid=59&lang=en

Web Map and Geodata Clients (3)

19Desktop Map and Geodata Clients (1)

Windows, Linux, Mac-OSX

Windows, Linux, Mac-OSX

Operating System:

CCLanguage:

WMS, WFS(-T), SFS, GML, KML

WMS, WFS, GML, WPS

OGC:www.qgis.orggrass.osgeo.orgWeb:GPLGPLLicense:20021982Birth:

Quantum GISGRASS

20Desktop Map and Geodata Clients (2)

Platform independent

Platform independent

Operating System:

JavaJavaLanguage:

WMS, WFS(-T), SFS, GML, WPS, SLD

WMS, WFS(-G), WCS, GML, KML, CSW, SLD

OGC:www.openjump.orgwww.gvsig.orgWeb:GPLGPLLicense:20022003Birth:

OpenJumpgvSIG

21Desktop Map and Geodata Clients (3)

Platform independent

MS Windows Operating System:

JavaC#, C++, Visual Basic, .NET

Language:

WMS, WFS(-T), SFS, GML, WPS, SLD

WMS, WFSOGC:udig.refractions.netwww.mapwindow.orgWeb:LGPLMozillaLicense:20042004Birth:

uDigMapWindow

22

• Currently the most of the Internet viewers are bi-dimensional (horizontal).

• Virtual globe: a 3D representation of the EarthAdvantages:• more immersive effects • intuitive interactions• ability to freely move around in the virtual

environment by changing the viewing angle and location

• capability of representing many different views on the surface of the Earth

Multi-D Map and Geodata Clients (1)

23

Comparison of Open Source Virtual Globes presented at FOSS4G-2010 Barcelona by Mathias Walker, Pirmin Kalberer(http://2010.foss4g.org/presentations/3690.pdf)

OssimPlanetOssimPlanet

NASA World Wind Java SDKNASA World

Wind Java SDK

gvSIG 3DgvSIG 3DosgEarthosgEarth Norkart VirtualGlobe

Norkart VirtualGlobe

Earth3DEarth3D

MarbleMarble QGIS 3DQGIS 3D

deegree 3Ddeegree 3D

Multi-D Map and Geodata Clients (2)

24

• SDK (Software Development Kit)• Virtual Globe • NASA Open Source Agreement License• Multi-Platform (Java: “Write Once, Run AnyWhere”)• JOGL (Java OpenGL 3D - Engine)• Client – WMS Server (v0.6 nightly builds) • Web: worldwind.arc.nasa.gov/java

NASA World Wind (Java SDK)

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Main interfaces:• Globe: represents the planet's shape and

terrain (ellipsoid and terrain)• Layer: overlaps geospatial information to the

Globe (images, icons, markers, 3D objects, …)• Model: combines the Globe and Layers• SceneController: controls the rendering of the

Model• View: controls the user's view of the Model

(location – camera settings, …)

WWJ SDK Architecture (1)

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WorldWindow

Model

Configuration (Global)

Globe

Tessellator

Notifier (Global)

Frame ControllerView

Layer

Cache

Web

Scene Controller

Application

Canvas

Window Environment (Swing, AWT, etc.)

WWJ SDK Architecture (2)

27

• Servers NASA – USGS (U.S. Geological Survey):

• DTM:• SRTM30Plus (30 arc-sec ~900m), SRTM3

v2 v4.1 (3 arc-sec, ~90m), ASTER (~30m), USGS NED (~30m, ~10m US only)

• IMAGERY:• BlueMarble (BMNG 1Km), i3-Landsat (15m),

USGS Ortho-Topo (1m US only), Urban Area Ortho (0.5 – 0.25m selected US city)

WWJ SDK Architecture (3)

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• Microsoft has allowed World Wind to incorporate Virtual Earth high resolution data for non-commercial use.

• It is possible to take from a whichever OGC compliant WMS server the geo-referenced images (and maps) we want to project on the globe.

• It is possible to take from specific WMSs, whose code is made available by NASA, the digital elevation models we want to superimpose to the geoid model implemented within the platform.

Construction of the scenario

WWJ SDK Architecture (4)

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time

WWJ-CLIENTRemote

Database

THEMATIC MAPS (2D)

RemoteDatabase

IMAGERY

RemoteDatabase

DTM

WMSSERVER(WWJ0.6)

WMS SERVER

WMS SERVER

2½D

Mapt=t0

Mapt=t1

Mapt=t2

• Projection on the Earth surface (2½D) of time varying thematic maps

3½D Model (1)

Scenario

WWJ SDK

3½D Model

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Original dataset – (Landsati7 + SRTM)Custom orthophotoCustom orthophoto + thematical mapCustom orthophoto + DTM + thematical mapCustom orthophoto + DTM + thematical map

3½D Model (2)

31

Thematical map: t = t0Thematical map: t = t1Thematical map: t = t2Thematical map: t = t3Thematical map: t = t4

3½D Model (3)

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3D Thematical MapsSHP FILE

A

C

D

B

E DBAttributes

(mdb, xml, …)

Natural domain (lake)

SHP FILE

A

B

C

D

E

DBAttributes

(mdb, xml, …)

Artificial domain (building)

4D Model Irregular shapes (1)

WWJ-CLIENTSHPLoader

GeometryBuilder

334D Model Irregular shapes (2)

A(t0) A(t1) A(t3) A(tN)A(t2) A(…)

3D Thematical Maps

… t

A

t1 t2 t3 tNt0

Feature attributes

34

time

WWJ-CLIENT

WMSSERVER

RemoteDatabase

IMAGERYWMS

SERVER

RemoteDatabase

3D MODEL(SHP)

ATTRIBUTES (DB)

RemoteDatabase

DTM

3DWEB SERVER

Attributet=t0

Attributet=t1

Attributet=t2

4D Model Irregular shapes (3)

Scenario

WWJ SDK

4D Model

354D Model Irregular shapes (4)

Olbia BuildingsMean Energy – Classification by ColorAttribute: Incentive – Thematized by ColorAttribute: Incentive – Thematized by Color and Height

36Doxel Model (1)

VOXEL (3D)v

WWJ-CLIENT

+time

(1D)

4D Thematic Map

NetCDFLoader

GeometryBuilder

NetCDF FILE

3D VARIABLES

DIMENSIONSATTRIBUTES

units

…

sourcesCOORDINATES

DOXEL (4D) (Dynamic voxel)

=v(t0)v(t1)v(t2)v(t3)

37

time

WWJ-CLIENT

WMSSERVER

RemoteDatabase

IMAGERYWMS

SERVER

RemoteDatabase

3D MODEL+

ATTRIBUTES(NetCDF)

RemoteDatabase

DTM

3DWEB SERVER

Attributet=t0

Attributet=t1

Attributet=t2

Doxel Model (2)

Scenario

WWJ SDK

4D Model

38Doxel Model (3)

v(t)

0 1 2 3 … N

v(t0) v(t1) v(t3) v(tN)v(t2) nodata

… t

v

t1 t2 t3 tNt0

39

LONGITUDE SECTION

GET ATTRIBUTE INFO

INFO

t

Attribute Value

Doxel Model (4)

HORIZONTAL SECTION

LATITUDE SECTION

• Interactions with the 3D model

40EST-WA (1)

(Environment Space and Time Web Analyzer)

•Metadata Viewer•2D Viewer•Data Filter

EST-WA2D 3D Geometry

Builder

Localcache

•4D Viewer(WWJ engine)

•2D Profile viewer

EST-WA3D

EST-WA

NetCDFdata

NetCDFdata

RemoteServer

http

DTMTexture

41EST-WA (2)

EST-WA3D

EST-WA2D: METADATA VIEWER EST-WA2D: DATA FILTER