[Talk-ca] BC2020i OSM Distributed Model and Education

john whelan jwhelan0112 at gmail.com
Fri Feb 2 23:06:50 UTC 2018

I think we need to identify the possible problem areas and those things
that would be useful to the students.  Not all students will have the same

The first is we really want to avoid students tracing building outlines in
iD.  Experience has shown they aren't very good at it.  JOSM and the
building_tool plugin works well but needs some preplanning.  If NRC LiDar
building outlines come off that gets round the problem.

First to get an understanding of GIS basics we need to reduce the idea of
an electronic map to two things.  Nodes and ways and we add tags to these.
You can call them different things but basically the nodes have a Longitude
and Latitude tag and the ways connect them.  Tag the way as a highway and
you have a road.  Tag it as a waterway and you have a river.  Four nodes
with four ways connecting them gives you the outline of a building.  Closed
ways are a special case and take tags such as building=yes.

Because my background is technical I would suggest a mention of XML format
of fire type .osm.  It evolved from SGML and is today used in many ways
including the internal file format for Microsoft Word.

An exercise might be to extract a building from OSM in JOSM save the file
and look at it in something such as notepad++

<osm version='0.6' generator='JOSM'>
  <bounds minlat='45.4755177' minlon='-75.4792151' maxlat='45.475623'
maxlon='-75.4790086' origin='CGImap 0.6.0 (20825 thorn-01.openstreetmap.org)'
  <node id='4664537912' timestamp='2017-02-04T23:55:55Z' uid='5241993'
user='DenisCarriere_import' version='1' changeset='45818106'
lat='45.475569' lon='-75.479028' />
  <node id='4664537993' timestamp='2017-02-04T23:55:56Z' uid='5241993'
user='DenisCarriere_import' version='1' changeset='45818106'
lat='45.475519' lon='-75.478978' />
  <node id='4664540965' timestamp='2017-02-04T23:56:33Z' uid='5241993'
user='DenisCarriere_import' version='1' changeset='45818106'
lat='45.475584' lon='-75.479242' />
  <node id='4664542944' timestamp='2017-02-04T23:56:59Z' uid='5241993'
user='DenisCarriere_import' version='1' changeset='45818106'
lat='45.475501' lon='-75.479064' />
  <node id='4664545143' timestamp='2017-02-04T23:57:28Z' uid='5241993'
user='DenisCarriere_import' version='1' changeset='45818106'
lat='45.475563' lon='-75.479041' />
  <node id='4664546447' timestamp='2017-02-04T23:57:43Z' uid='5241993'
user='DenisCarriere_import' version='1' changeset='45818106'
lat='45.475484' lon='-75.479048' />
  <node id='4664547023' timestamp='2017-02-04T23:57:53Z' uid='5241993'
user='DenisCarriere_import' version='1' changeset='45818137' lat='45.47547'
lon='-75.479126' />
  <node id='4664547073' timestamp='2017-02-04T23:57:53Z' uid='5241993'
user='DenisCarriere_import' version='1' changeset='45818137'
lat='45.475643' lon='-75.479122' />
  <way id='472241168' timestamp='2017-10-25T00:16:10Z' uid='5633991'
user='Matthew Darwin' version='3' changeset='53222843'>
    <nd ref='4664547073' />
    <nd ref='4664545143' />
    <nd ref='4664537912' />
    <nd ref='4664537993' />
    <nd ref='4664546447' />
    <nd ref='4664542944' />
    <nd ref='4664547023' />
    <nd ref='4664540965' />
    <nd ref='4664547073' />
    <tag k='addr:housenumber' v='767' />
    <tag k='addr:street' v='Merkley Drive' />
    <tag k='building' v='detached' />
    <tag k='building:levels' v='2' />
    <tag k='source' v='City of Ottawa' />

You can see from the idents around way and /way the tags for the building
are grouped together.  The important thing about .xml are the tags.  In a
conventional database if a tag is unrecognised strange things can happen.
With XML only data from within recognised tags are used which means new
tags can be added without affecting the normal processing.  It is often
used as a file transfer format from one system to another.

On a less technical level often people have difficulty in grasping that the
map shown on www.openstreetmap.org is not the real live map.  It would be
useful to mention the concept of rendering and to show the map rendered in
different ways.  OSMand comes to mind.  Look at map layers on

For the building project itself it would be useful to look at how we
extract the data from the map.  With paper map you'd need to count the
buildings but with an electronic map a program can count them for you.

It would be useful if someone could produce a sample in R that takes a .osm
file and counts the buildings.  A task from that would be to extend it to
count the number of two storey (story) buildings.  Legally in Canada by act
of parliament "storey" is used rather than the American "story".  Discuss

Local knowledge is always preferred in OSM.  So I would suggest for the
mapathon ensure the building outlines are in place then ask the students to
enrich the map by adding tags.  Run R before and after to show the
differences and the impact.

Dig into https://wiki.openstreetmap.org/wiki/Education and see if there is
anything useful.

Be aware there are many different points of view within OpenStreetMap, as
an example map features and taginfo often differ.  Map features is
someone's idea of this is how to tag taginfo is this are the tags that have
been used.  Could students explain why this is so?

OpenStreetMap isn't just about geography and producing a printed map.
Maperitive is an excellent tool for creating your own map either to the
screen or printed by the way and it can be customised.  Making a simple
change is easy but its almost a programming language in its own right.

The suggestions may or may not be relevant but they cover a fairly wide
range of subjects.

Have fun

Cheerio John

On 30 January 2018 at 10:49, Jonathan Brown <jonabrow at gmail.com> wrote:

> I don’t mind reviewing the OSM education wiki for lessons learned and
> “promising practices” and seeing how it might inform the design of a
> mapathon event aligned to the K-12 curricula and postsecondary capstone
> project model. It will be messy, but that’s the nature of the beast. To use
> the jargon, start small, fail fast and apply what you learn to the next
> event.
> Durham Region is planning on hosting a mapathon event as early as this
> March. I’m working with the GIS Supervisor who also teaches GIS to 2nd
> year environmental science students at Durham College. I also have a
> teacher who is very good at working with students who normally would not
> participate in these kinds of events, but who have street knowledge.
> Jamie Boyd and Moses Iziomon at the Treasury Board’s Open Government
> branch may have some funding to support Alessandro’s group in helping to
> engage the OSM “crowdmappers” and citizen science practitioners. This could
> align to their 2 year open government plan http://open.canada.ca/en/
> 4plan/creating-canadas-4th-plan-open-government-2018-20. They are looking
> for workshop ideas for early May.
> Does anyone know of OSM expertise that we could tap into for a mapathon
> event in the Durham Region? Thanks.
> Jonathan
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