Use OpenLayers for web mapping interface (replace Intermap with OL)

Date	2008/06/20
Contact(s)	etj, francois
Last edited	Timestamp
Status	draft
Assigned to release	to be determined
Resources	?

Overview

Replace IM with a more responsive map client.

Current known initiatives :

• In the context of a project in Switzerland, Camptocamp team has been working on setting MapFish as a client for catalogue. See proposal ​http://trac.mapfish.org/trac/mapfish/wiki/Proposals/Catalogue
• NGR (​http://www.nationaalgeoregister.nl/geonetwork/srv/nl/main.home)
• Mali (Jean) - start from geocat.ch
• MEDWIP (​http://www.emwis.net/geonetwork/)

Some screenshots

Proposal Type

• Type: GUI Change, Module Change
• App: !Intermap
• Module:

Links

• Documents: ​OpenLayers, ​GeoExt, ​MapFish, ​Ext.js
• Email discussions:
• Other wiki discussions:

Voting History

• No votation requested yet.

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Motivations

The current implementation of the map client needs an image transfer from the Intermap server every time something in the map changes.
OpenLayers has a quite different architecture, where many efforts has been spent in order to minimize heavy data transfers from map servers to the client. Also many map operations are ready out of the box. Removing the IM webapp in order to simplify the installation is also a nice target.

The main objectives are :

• add support for some Intermap missing functionnalities:
  • allow simple vector feature support (bbox highlight, define bbox or bounding polygon in the editor)
  • allow non WGS84 projection support
• improve :
  • map viewing (tiling, layer tree)
  • pdf printing

GUI will be mainly written using javascript. It will be easier to update the layout as it will use div and css (instead of existing deeply nested table layout). A jeeves service named "home" is using XSL to read localized string for the UI. Then all the layout will be HTML and JS.

Proposal

Catalogue search form

Search form is composed of a simple and advanced mode. Search criteria available by default are:

• simple form
  • full text
  • region or bounding box
• • title
  • abstract
• options
  • sortBy
  • number of restuls per page
  • output

Function	Available in 2.2	geocat.ch	NGR	Available	Comments

Catalogue search results

Function	Available in 2.2	geocat.ch	NGR	Available	Comments
Metadata view		X			Popup (modal?) in default view mode ? Button to access to advanced view ?

Map Features

One "mini-map" is used to define search criteria and higlight bounding box of search results. One "big-map" is used to make your map and display geographic data using OGC Services.

Common map features ===

Function	Available in 2.2	geocat.ch	NGR	Available	Comments
Zoom in/out	X	X			default OL navigation or in map toolbar
Zoom slider		X			default OL navigation
Panning	X	X			default OL navigation or in map toolbar
Zoom to full extent	X	X			double click the metadata record to go to the metadata extent

Mini-map features ===

Function	Available in 2.2	geocat.ch	NGR	Available	Comments
Metadata Bbox higlighter		X

Big-map features ===

Function	Available in 2.2	geocat.ch	NGR	Available	Comments
Layer tree	X	X			GeoExt layer tree (add, remove, view, reorder, transparency)
Pdf printing	X	X			MapFish print module, TODO send by email
WMC	X	X			OL WMC support, TODO email context

Intermap feature not available in the proposal ===

Function	Available			Comments
Markers & annotation				Not planned yet

To be discussed

• Question
  • search form : link to a WFS server to define region?
  • architecture : Which version of the lib? Use svn:external ?
• From where to start ?
  • geocat.ch :
    • needs to be migrated from MapFish to GeoExt (MapPanel mainly - started on other project in Camptocamp).
    • Build CSW query from search forms ​https://geonetwork.svn.sourceforge.net/svnroot/geonetwork/sandbox/geocat.ch/trunk/web/geonetwork/scripts/mapfishIntegration/searchTools.js
    • Tocheck : GetDomain support

Required librairies :

• OpenLayers (2.8?)
• GeoExt (0.5?)
• MapFish (?)

The GeoEditorViewer proposal add the OpenLayers 2.8 and GeoExt 0.5 libs.

Related works :

• CSW protocol support in OpenLayers ​http://trac.openlayers.org/ticket/2133
• CSW components in GeoExt (GetRecords & GetDomain operation support) ​http://trac.geoext.org/ticket/87

Backwards Compatibility Issues

• JS file size for ext.js ​http://extjs.com/blog/2008/11/18/ext-cdn-custom-builds-compression-and-fast-performance/
• js-build is used to compress required JS libs. See GeoEditorViewer

Risks

Participants

• Francois (geocat.ch)
• Patrick (geocat.ch)