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RE: Best Practices narrative update

From: Linda van den Brink <l.vandenbrink@geonovum.nl>
Date: Mon, 1 Aug 2016 11:01:44 +0000
To: SDW WG Public List <public-sdw-wg@w3.org>
CC: Jeremy Tandy <jeremy.tandy@gmail.com>, Payam Barnaghi <p.barnaghi@surrey.ac.uk>
Message-ID: <13F9BF0BE056DA42BFE5AA6E476CDEFE725F4A5F@GNMSRV01.gnm.local>
Hi all,

I inserted this into the BP as a new appendix, section 12.

See http://w3c.github.io/sdw/bp/#narrative


Van: Jeremy Tandy [mailto:jeremy.tandy@gmail.com]
Verzonden: zaterdag 30 juli 2016 02:42
Aan: SDW WG Public List; Linda van den Brink; Payam Barnaghi
Onderwerp: Best Practices narrative update


As part of the recent flurry of activity around the best practices document, I have been trying to refine the urban flood response narrative that we will use to provide context to our examples.

My main aim has been to make each “activity” far more modular, therefore enabling a reader to identify with one of the Actors; Frederick, Florence, Carole etc.

I’m intending that this will form an Appendix in the BP doc.

The current status of this section:

  *   more work required; including adding further details from BP_Narrative_2<https://www.w3.org/2015/spatial/wiki/BP_Narrative_2> ... the examples themselves need much more detail so that they will be useful to practitioners
  *   need to clarify what is narrative (story) and what is technical example
  *   need to add clear headings for each section
  *   describe each of the Actors upfront (?) along with a quick summary of their task/activity to help readers find things that are relevant

This already has a lot of words in it; I think we also need to find a way to ‘compress’ the sprawl … perhaps using some javascript magic like Frans et al did in the UC document.

So- even though there’s much work left to do, I wanted to share this with you all today. Unfortunately, I’ve run out of time to work on this … and am headed for vacation tomorrow, returning 15-August.

In the mean time, maybe one of my fellow editors can insert this (more or less verbatim) in to the BP doc draft as a new Appendix … or share it as a Google Doc (or similar) if folks want to do some collaborative editing.

Best Regards, Jeremy

(“see” you all in two weeks)


Note: Names and places used in this scenario are fictional, procedures and practices may not reflect those used in the real world. Our intent is to provide a coherent context within which the best practices can be illustrated. We <strong>do not</strong> attempt to provide best practice for management of flooding events. However, many of the procedures discussed are based on information from [flood-risk-and-water-management-in-the-netherlands<http://unitedkingdom.nlembassy.org/binaries/content/assets/postenweb/v/verenigd_koninkrijk_van_groot_brittannie_en_noord_ierland/nederlandse-ambassade-in-londen/import/key-topics/flood-risk-and-water-management-in-the-netherlands-a-2012-update1.pdf>].

Nieuwhaven is a flourishing coastal city in the Netherlands. In common with much of the Netherlands, the low lying nature of Nieuwhaven make it prone to flooding from both rivers and the North Sea. To mitigate or reduce risks to homes and businesses, significant investment has been made to flood control and water management infrastructure.

Flood Risk Management and Water Management are integrated in the Netherlands. By combining [responsibilities for] daily water management and flood risk management, the same people are involved who have a detailed knowledge of their water systems and flood defences.


[source: §2.3 “Multi-layer safety” for Flood Risk Management, flood-risk-and-water-management-in-the-netherlands<http://unitedkingdom.nlembassy.org/binaries/content/assets/postenweb/v/verenigd_koninkrijk_van_groot_brittannie_en_noord_ierland/nederlandse-ambassade-in-londen/import/key-topics/flood-risk-and-water-management-in-the-netherlands-a-2012-update1.pdf>]

Flood risk management can be separated into three layers:

(3) Flood alerts, evacuation, response and recovery (civil protection issues); both organisational and physical measures (e.g. identifying, checking, repairing and signalling evacuation routes).

(2) Spatial planning issues; reducing the impact of flooding through planning measures.

(1) Flood protection; constructing flood defences to reduce the probability [of inundation and the impact of flooding]

Our scenario concentrates of element (3).

The Nieuwhaven Water Board (regional water management authority) is the independent local government body responsible for maintaining the system of dikes, drainage, canals and pumping stations that are designed to keep the city and surrounding environment from flooding.

> typical SDI approach?

> include designated “flood zone” features, waterbody features, dikes and control infrastructure etc.

Based on assessment of historical flooding events, Newhaven Water Board is able to determine the extent of flooding that would occur as the result of hypothetical storm surge and river flooding events.

> inundation extent from hypothetical scenarios

> vector geometries for the inundation extent based on assessment against high-resolution DEM (Digital Elevation Model) / DTM (Digital Terrain Model) derived from photogrammetry & lidar

> API enables users to define the geometry resolution (from 1m resolution up to 50m?) they need for their application using a query parameter [e.g. to manage the volume of complex geometries]

Frederick …

Municipal emergency services, public health authorities and water boards are grouped according to a “safety region” in order to establish a multi-disciplinary “emergency team” for crisis management. This helps to ensure that there is effective communication between those responsible for public safety and those responsible for flood control and water management.

Each safety region prepares systematically for its own specific characteristics, based on available capabilities. This plan, the “Flood Response Plan”, includes evacuation strategies that are developed in response to hypothetical flooding events. Scenarios are prepared beforehand and carefully considered. The emergency team must be prepared at all times to deliver an assessment on a disaster / incident scenario and advise on proposed interventions, e.g. evacuation and deployment of temporary flood defences.

The numbers of citizens impacted by each hypothetical flooding event are determined by cross-referencing the areas affected by surface water flooding with census data.

Statistics Netherlands<https://www.cbs.nl/en-gb/about-us/organisation> (CBS) publishes reliable and coherent statistical information which respond to the needs of Dutch society and is responsible for compiling official national statistics.

> Does CBS provide city-level census data?

CBS makes use of OData, the Open Data Protocol v4, to provide open datasets for use by third parties. Furthermore, CBS provides a search interface to help a user find the dataset of interest [or is this supported through discovery via the common search engines]

[CSV is another option]

CBS also provides metadata for the census dataset, in both human- and machine-readable forms.

A download of all the data may leave the data user with a large amount of information to work with, when they are only interested in the subset of areas affected by flooding. Therefore it is desirable that the publisher makes the data available via an API, where the user can select the area of interest and retrieve relevant information, possibly also narrowing down their choice by other statistical dimensions.

Census data naturally takes the form of a statistical 'data cube', with statistical dimensions of area, time, gender, age range etc. A useful standards-based approach to making the data available would be to represent it as RDF, using the RDF Data Cube Vocabulary [VOCAB-DATA-CUBE<https://www.w3.org/TR/vocab-data-cube/>]. This offers a standards based way to represent statistical data and associated metadata as RDF. API access to the data could be provided via a SPARQL endpoint, or a more specific API. The Linked Data API, implemented by Epimorphics’ ELDA, provides a useful mechanism to expose simple RESTful APIs on top of RDF/SPARQL.

Florence …

Population data from a census is typically broken down by area, gender, age (and perhaps other statistical dimensions) and relates to a particular time.

CBS uses established URLs to identify each each administrative area for which population data is available. Details of the administrative areas for Nieuwhaven are published by the municipal government. This information includes the geometry for each administrative area.

Data about administrative areas are often useful - perhaps they represent one of the most popular spatial datasets. In this case they are useful for coordinating the emergency response, i.e. predicting and tracking which neighbourhoods or districts are threatened. Because the names of local administrative areas such as neighbourhoods are very well known they are also useful for communication with citizens, i.e. letting them know if their neighbourhood is threatened by the flood or not.

Because the administrative area datasets is quite popular, all kinds of data users will want to use it - not only GIS experts. To enable them to find the data on the web, it was published in such a way that search engines can crawl the data, making the data findable using popular search engines.

> publish administrative areas with geometry

> geometries published with national CRS via SDI (this could be converted in the browser using proj4.js)

Carole …

By cross-referencing the population statistics, administrative areas and surface water flooding extent (e.g. by calculating the intersection of the flood with administrative areas), the number of citizens impacted by each hypothetical flooding event can be estimated.

Once the number of citizens that need refuge has been determined, the emergency teams can designate public buildings, such as schools and sports centres, as evacuation points and define safe transit routes to get to those points.

The municipal government published details of the built infrastructure within Nieuwhaven, including public buildings and transport infrastructure.

> each feature is uniquely identified

> each feature is indexed by search engines

> dataset is published as vector tile-set (like OSM)

The municipal government also publishes metadata describing each dataset (DWBP-BP1) that, besides free text descriptions (e.g., title, abstract), include the following information:

  *   the type of objects/features described - e.g., with a thematic classification (DWBP-BP2)
  *   spatial coverage / temporal coverage - to identify if data match the area of interest
  *   coordinate reference system(s) used - to correctly interpret geometries
  *   spatial resolution - to identify data with the right level of detail
  *   distribution format(s) and API to get access to the data (at a different level of granularity) - to identify those datasets consumable by the intended application(s) (DWBP-BP4, DWBP-BP13)
  *   date of last modification - to see whether data are up to date (DWBP-BP8)
  *   the parties responsible for the creation and maintenance of the data - to verify data authoritativeness (DWBP-BP6)

To facilitate data discoverability, metadata should be published via<http://schema.org> different channels and formats (DWBP-BP22). Typically, such metadata are maintained in geospatial catalogues, encoded based on ISO 19115<https://en.wikipedia.org/wiki/Geospatial_metadata> - the standard for geospatial metadata. In addition to this, such metadata can be served in RDF, and made queryable via a SPARQL endpoint; e.g. GeoDCAT-AP<https://joinup.ec.europa.eu/node/139283/> provides an XSLT-based mechanism<https://webgate.ec.europa.eu/CITnet/stash/projects/ODCKAN/repos/iso-19139-to-dcat-ap/browse> to automatically transform ISO 19115 metadata into RDF, following a schema based on the W3C Data Catalog Vocabulary (DCAT).

This solution can be further enhanced by making data discoverable and indexable via search engines. The advantage is that this would allow data consumers to discover the data even though they do not know the relevant catalogue(s), and to find alternative data sources.

This can be achieved, following Search Engine Optimisation (SEO) techniques, by embedding metadata in catalogue’s Web pages, with mechanisms like HTML-RDFa, Microdata, and Microformats. Examples of this approach include the following ones:

  *   In the Geonovum testbed<https://geo4web-testbed.github.io/topic4/>, dataset pages from a geospatial catalogue embed metadata, represented by using the Schema.org<http://schema.org> vocabulary, directly generated from the relevant ISO 19115 records.
  *   The experimental GeoDCAT-AP API<https://webgate.ec.europa.eu/CITnet/stash/projects/ODCKAN/repos/iso-19139-to-dcat-ap/browse/api> allows data publishers to serve ISO 19115 records in different RDF serialisation formats, including HTML+RDFa, on top of a geospatial catalogue and/or an OGC Catalog Service for the Web (CSW).

> publish dataset metadata

Lorenzo …

Temporary flood defences are common where roads and railways cross permanent flood defences or are built up on boulevards along rivers. Also, temporary flood defences are also deployed where dikes have not passed their annual visual inspection or 5-yearly assessment. Information regarding the condition of dikes cannot be incorporated into the plan, and must be considered during an actual flood event.

> individual transport network segments and flood defence features are uniquely identified

> spatial relations are used to define where transport infrastructure cross flood defences, and hence quickly determine where to deploy temporary flood defences without the need for detailed spatial analysis … this can be used to demonstrate 3rd-party linking; e.g. the spatial relations are published by an organisation that owns nether of the target datasets

> locations for temporary flood defences are provided to the relevant emergency services teams

James …

Storm surge and river flood warning services are provided by the National Water Management Centre (WMCN) at Rijkswaterstaat<https://www.rijkswaterstaat.nl/>, who are responsible for the design, construction, management and maintenance of the main infrastructure facilities in the Netherlands such as the main road network, the main waterway network and water systems.

The storm surge warning service is triggered by storm surge alert from the Royal Netherlands Meteorological Institute (KNMI), the Dutch national weather service. A forecast combination of heavy rainfall, high-tide and storm makes it likely that a flooding will occur in the next 120 hours. Specialists use meteorological, hydrological and urban flood prediction models within the Flood Early Warning System (FEWS) to estimate peak water-levels, when these will occur and which area will likely be flooded.

> Note. “Flood Early Warning System” is the name of a system provided by Deltares; is it sufficiently generic or should we avoid this terminology?

The Storm surge warnings consist of predicted maximum water levels and a general description of wind and tide. 10-minute water level forecasts are computed and distributed, including details of wave run-up and overtopping for dikes.

Every 6 hours, new meteorological predications are incorporated into the flood prediction, resulting in a new version of the 10-minute water level forecast dataset being made available.

> landing page (with descriptive metadata) for each forecast dataset

> entire forecast dataset available in a number of (compact binary) formats for offline use (e.g. NetCDF, HDF5)

> ”current" forecast uniquely identified

> exposed via a self-describing restful API; subdivided by time (each time-step listed in metadata)

> use RDF Data Cube to describe the dataset structure

> whole time-slice available as covjson

> simple point data extraction (in WGS84 coordinates); covjson point feature with water depth time series

> simple bbox extraction (in WGS84 coordinates); covjson

> use covjson data to illustrate (1) depth of flooding, (2) changes in inundation through time

Felix …

The emergency team for the Nieuwhaven safety region compare the predictions for the forecast flooding event against the hypothetical scenarios developed in the Flood Response<http://www.crisis.nl> Plan to determine which of the prepared response plans to execute.

Based on this assessment, the imminent flooding event requires a number of temporary flood defences to be deployed and evacuation of some districts of Nieuwhaven.

The emergency team identify where additional temporary flood defences are required due to any dikes that are in a state of disrepair (e.g. having failed their annual or 5-yearly assessments).

> cross reference the location of each damaged dike with predicted high-water level, determined via an API call into the 10-minute water level forecasts to extract a water level time-series for a given point to determine if the water level is predicted to exceed a threshold, in which case, temporary flood defences will be required.

Details of the emergency and the evacuation plan must be communicated to citizens. They are kept informed during and prior to the event using multiple channels:

  *   local radio and television networks
  *   news and medi<http://schema.org>a agencies; television, radio and >>> on-line <<<
  *   official national Government website www.crisis.nl<http://www.crisis.nl>, including specific information about flooding events<http://www.crisis.nl/wees-voorbereid/overstroming.aspx>
  *   cell broadcasting via the Government’s NL-Alert<http://www.crisis.nl/nl-alert> system, providing SMS message alerts to all mobile phones in the vicinity of a life a<http://schema.org/Place>nd health threatening emergency
  *   air raid sirens

The evacuation plan must be discoverable by the public. The intent is for each plan to be both human (primarily) and machine readable. The requirement for machine readability is mostly to support automated discovery of the content via web search. The URL itself ideally should also be "human friendly" as it should be easy to share verbally in addition to being embedded and linked to from other web pages.

While making the plan<http://schema.org>s clear and understandable to human readers is well understood (and beyond the scope of this best practices document!). The challenge is to make the content machine readable. The use of a simple tag based schema using microdata, RDFa or JSON-LD is recommended. A simple first step might be to use the schema.org<http://schema.org> "Event" item tag <div class="event-wrapper" itemscope itemtype="http://schema.org/Event">, which has useful generic properties of date, location, duration etc. The places of evacuation refuges (e.g. schools, sports centres etc) should be tagged using the generic “http://schema.org/Place”.

> publish simple, authoritative Web pages that describe the evacuation plans; include structured mark-up to help search engines index the rich content; each evacuation plan must be uniquely identified

> the evacuation plans link to the <a>spatial things</a> (e.g. schools, sports centres, administrative areas etc.) designated as refuges etc.

Details of the evacuation route should be provided ideally as a textual description (perhaps machine readable using the schema.org<http://schema.org> "TravelAction<https://schema.org/TravelAction>" item, although this is rather limited) and a graphical representation. Potentially route information could be encoded using a format such as OpenLR<http://www.openlr.org/index.html> but this has not achieved widespread adoption.

> describe transit routes

Bryan …

News and media agencies provide Web applications that help communicate the evacuation to citizens as effectively as possible; e.g. by creating simple Web applications that direct one to the correct evacuation plan based on their postal code or online mapping tools. media agencies may cross-reference evacuation plans with Features that have non-official identifiers; e.g. from What3Words (W3W) or GeoNames.

> simple App to help people determine if they will be flooded ... simple lookup based on postcode area; x-ref postcode area with predicted surface water extent (from forecast dataset) via spatial analysis of geometries; use API into forecast dataset to extract water-level time series for a given location

Vernon …

During a flood event, the Flood Response Plan indicates that emergency services will have to focus their efforts on reducing the number of fatalities. This means that if an evacuation order is given, the efforts of the emergency services will be focused on traffic control and on non self reliant groups.

As the flood event progresses, the emergency services provide evacuation assistance for the vulnerable, such as the residents of care homes.

The municipal public health authority publishes details of care homes and other health care facilities on-line as open data, using a simple CSV format.

> CSV formatted spatial data … either using well-known-text encoded geometry_or_ providing an address that can be geocoded? … It is important that the structure and meaning of the data is documented, by providing a definition for each column header and information on the type of data to be expected in the cells. This should follow the approach defined in the W3C Metadata Vocabulary for [TABULAR-METADATA<http://www.w3.org/TR/tabular-metadata/>]

Jan …

The position of each vehicle used by the emergency services is tracked in near real-time using GPS. The coordinators within the emergency team are able to view both current position and where the vehicles have been; gauging the evacuation progress against the Flood Response Plan.

> moving features; where “geometry” changes with time

Ricardo …

During floods and storm surges, professionals (often aided by trained volunteers) constantly monitor all flood defences. Measurements include: water level, wave height, wind speed and direction.

The emergency team use these observations to monitor the rising water levels to ensure that these are consistent with the predictions (both in terms of timing and peak water-level) in case additional interventions, such as evacuating more districts, are required.

A real-time data stream of water level at a specific location within Nieuwhaven’s canals is published from an automated monitoring system operated by the Water Board; e.g. a Web-enabled sensor.

> metadata about the data stream enabling discovery and interpretation of the data stream values; e.g. what quantity kind is being measured with which units of measurement, what is the sensor etc.

> relate the sensor (and the data-stream it provides) to the water body whose water level it is intended to monitor

> describe the sensor location

> SensorThings API example; what about use of protocols other than HTTP; e.g. MQTT?

Megan …

Fortunately, the prediction is sufficiently accurate that the evacuation plan remains effe<https://twitter.com/leoniemellor/status/738884030511222785>ctive. However, the emergency team notice that the water level in one particular sector is higher than predicted- and rising. Further analysis indicates that an automated control gate has malfunctioned.

A team is dispatched to use the manual override. The manual control is located using relative positioning.

> the manual override / control is located using relative positioning

Tomas …

During the flood, citizens themselves become engaged with the flood event; they use social media to post geo-tagged messages regarding their observations of the flood (“the #flood has reached my home” or “Mount Pleasant Road closed at junction with Acacia Avenue #flood”, perhaps accompanied by photographs) or offer localised help (“come charge your phone at my porch #floodresponse”).

The aggregated social media messages are used by the emergency team to complement the monitoring data provided by the Water Board, tracking the progress of the flooding event in near real-time.

> social media, water extent … VGI … https://twitter.com/leoniemellor/status/738884030511222785 … aggregated social media posts; situational awareness … how to reconcile place names with resources formally identified with URLs? … especially where local or informal place names (with ‘fuzzy’ boundaries) are used (e.g. “north of Downtown”)

> … ambiguity: “#flooding the water is 2 feet deep at my house”

> … social media platform providers drive collection of particular information from users of the platform

> … or volunteers might blog, creating content in HTML using a publishing App

> geotagging photos of flood extent ... using EXIF data from photos ... provide an API to search that resource [Instagram] ... emergency responders use this to track the progress of the flood against prediction

Ron, Heather, Charles …

Due to the prioritisation of emergency services elsewhere, the Flood Response Plan assumes that the general public will have to be self reliant or resilient for a number of days.

Using social media, local businesses offer services to those affected by the flood; for example, a local bakery offers food and water and asks for help to move these supplies to the evacuation refuge nearby.

> #floodresponse ... messages are geotagged (location label) but also use HTTP URI to precisely identify the location (e.g. from W3W)

Susan and Patrick …


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Received on Monday, 1 August 2016 11:43:26 UTC

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