Search Engine Optimization (SEO)

Introduction

The main objective of the SEO (Search Engine Optimization) work is to provide crawlers information about the content of map.geo.admin.ch in order to let the user finds map.geo.admin.ch with a search engine.

Principles

Create sitemaps containing permalinks
Assure metadata (page title, keywords, description, twitter/fb tags) is correct and available
Bot detection: _escaped_fragment_= parameter
Snapshot based (until August 2014) a. Create a service adding static metadata information for the crawlers b. Redirect crawlers to this service
Depend on JS rendering of google (since August 2014) a. Add metadata when bot is crawling page (depending on permalink content)

Implementation

Create sitemaps containing permalinks

Current Sitemaps

All public topics
All layers of all public topics
The above in all 4 languages
All adresses from the register layer (2 million links)

Ideas for other sitemap permalinks (TODO)

Administrative units (cities, districts, cantons and npa)
Features (national maps division etc...)
Combinatory of categories (cities + hiking layer, cities + national map division etc...)

Create a service adding static metadata information for the crawlers

Metadata information are placed in a special popup instance at the start of the html document. Otherwise, the page recieved by the crawlers is identical to standard map.geo.admin.ch; in order to avoid cloaking (see references below). The input for the meta-information is the permalink passed to the application. All additional information will be derived from these parameters.

This approach allows the crawlers to index links found in our sitemaps (category A), but also links found in the wild (category B), like twitter, facebook, blogs, journals, etc. Category B links usually increase the ranking of a given link.

Parameters that add metadata for crawlers

layers - we fetch all metainformation (i button in application) of every layer specified and add it to the metadata popup. As this is on top, Google is already using this information in the description of the results. See https://www.google.ch/?gws_rd=cr&ei=zdFXU_qvFITdtAb79YCIDA#q=map+geo+agnes&safe=off
swissearch parameter -> as this automatically opens the results of the search terms, these results will be visible for the web crawlers and will be indixed accordingly.
Features -> if features are specified in the URL (as layerId=featureid1,featureid2), the htmlpopup of these features are added to the injected data
use y/x[/zoom] parameter to geolocate the map. This injects location data based on Y, X and zoom values of the permlink. It only happesn when >= 5. Add all results of an identify request @ Y, X with following layers (pixel tolerance 10 pixels): 'ch.swisstopo-vd.ortschaftenverzeichnis_plz', 'ch.swisstopo.swissboundaries3d-gemeinde-flaeche.fill', 'ch.swisstopo.swissboundaries3d-bezirk-flaeche.fill', 'ch.swisstopo.swissboundaries3d-kanton-flaeche.fill'. Also, add x number of closest results from search request with bounding box of 4km^2 around Y,X with following layers), 'ch.swisstopo.vec200-names-namedlocation' -> x = 3 and 'ch.bfs.gebaeude_wohnungs_register' -> x = 1 PR ready. Those names are inserted inside a link tag (a) with the href being the requested url.

More ideas

Topics -> some topics have default active layers -> add these to the metadata

Redirect crawlers to this service

Technical Overview

How the crawler will get his snapshot

Details

We are using meta tag fragment to trigger the web crawlers to append _escaped_fragment_= parameter to the requested URL. See https://github.com/gjn/mf-geoadmin3/blob/master/src/index.mako.html#L25
The webcrawler will crawl the url including the _escaped_fragment_= parameter. If apache detects such an url, it will redirect to the snapshot service. See https://github.com/gjn/mf-geoadmin3/blob/master/apache/app.mako-dot-conf#L30
The snapshot service will launch a phantomJS service and will call the URL with the snapshot=true parameter. This will trigger the meta-data inclusion into the map. See https://github.com/gjn/mf-geoadmin3/blob/master/src/components/seo/SeoDirective.js#L77 What data is included is described above.