<div dir="ltr"><div><div><div><div><div>I am very cautious about any of this kind of measurement for the following reasons:<br></div>1) the results will be very difficult to standardise<br></div>2) the effort is far beyond that what a mapper can reasonably do.<br><br></div>If you wanted to do it properly you needed to mount a measuring device in such a way that it looks downwards to measure the reflected light, may be on some kind of arm protruding from your vehicle (bicycle in my case) and then record continuously the measurement. Now you have to consider the parameters:<br></div><div style="margin-left:40px">measurement device characteristics<br></div><div style="margin-left:40px">distance from the ground<br></div><div style="margin-left:40px">weather conditions (we would need to define "standard dry weather", because with rain you will have the problem of direct reflectosn of light sources)<br></div><div style="margin-left:40px">signal integration parameters (do you average over 10m for example?)<br></div><div><div style="margin-left:40px">and most likely others.<br></div><br></div><div>Then you still have the problem of how to define the illumination quality of a stretch of cycle path. Assume you have a 100m stretch with nice illumination but there is a tiny S-bend exactly overshadowed by an evergreen tree, which produces a pitch dark spot of 10m at a dangerous point. What do you do? Put an illumination value every 5 meters or, and that's what I would do, mark the entire 100m stretch as lit=very_poor (or something similar).<br></div><div><br></div>Constructive and realistic suggestions are welcome.<br><br></div>Volker<br></div><div class="gmail_extra"><br><div class="gmail_quote">On 18 January 2015 at 11:34, Warin <span dir="ltr"><<a href="mailto:61sundowner@gmail.com" target="_blank">61sundowner@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div>On 18/01/2015 5:14 PM,
<a href="mailto:tagging-request@openstreetmap.org" target="_blank">tagging-request@openstreetmap.org</a> wrote:<br>
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<blockquote type="cite">
<pre>Date: Sun, 18 Jan 2015 00:14:36 -0600
From: "John F. Eldredge" <a href="mailto:john@jfeldredge.com" target="_blank"><john@jfeldredge.com></a>
To: "Tag discussion, strategy and related tools"
<a href="mailto:tagging@openstreetmap.org" target="_blank"><tagging@openstreetmap.org></a>, Volker Schmidt <a href="mailto:voschix@gmail.com" target="_blank"><voschix@gmail.com></a>
Subject: Re: [Tagging] Tagging road illumination quality
Message-ID:
<a href="mailto:14afbadb528.27a5.8c042f3e6e983dd0f57452e62f7f805b@jfeldredge.com" target="_blank"><14afbadb528.27a5.8c042f3e6e983dd0f57452e62f7f805b@jfeldredge.com></a>
Content-Type: text/plain; charset="utf-8"; Format="flowed"
You could use a light meter to measure how bright the light is. That isn't
the only factor in the suitability of the lighting, but it is objective.</pre>
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<big><br>
My 'smartphone' can give a light reading -Andriod using app 'GPS
Status' in lux or foot candle. There should be others that do the
same kind of thing. Uses the camera function to determine the
light from the exposure. But 'we' will need guidance on how best
to measure it. Possibly pointing it at the ground immediately
under the light for a hi reading, and anothe midway between two
lights for a low reading and take the average? Maybe a google will
turn up some ideas? The phones won't be accurate but should be
good enough for an indication. </big><br><span class="">
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<div>--
John F. Eldredge -- <a href="mailto:john@jfeldredge.com" target="_blank">john@jfeldredge.com</a>
"Darkness cannot drive out darkness; only light can do that. Hate cannot
drive out hate; only love can do that." -- Martin Luther King, Jr.
On January 16, 2015 11:18:33 AM Volker Schmidt <a href="mailto:voschix@gmail.com" target="_blank"><voschix@gmail.com></a> wrote:
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<pre><span>> </span>I would like to enter illumination quality for bicycle infrastructure
<span>> </span>(cycleways) in OSM.</pre>
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<pre><span>> </span>Any suggestions welcome
<span>></span>
<span>> </span>Volker</pre>
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