[Talk-ca] Mapping cut blocks in "wooded" areas

Bryan Crosby azubryan at gmail.com
Mon Mar 7 18:52:45 GMT 2011


Some more thoughts,

 

Despite the idealism displayed by mapping cutblocks, I really believe that
this should not become standard practice as there are too many variables at
work that would interfere with the accuracy, and integrity of the dynamic
features in question.  Until that can be addressed (possibly with the next
CANVEC release) I don’t believe we should be aggressively pursuing this.  I
encourage users to fire up Bing sat tiles for Northern British Columbia to
get a feel for the massive numbers of openings.   I will adamantly state now
that I will not, ever map cutlblocks for any CANVEC I import unless I’m
provided with solid data to properly tag the blank openings.  

 

Bryan

 

From: Daniel Begin [mailto:jfd553 at hotmail.com] 
Sent: March-07-11 10:22 AM
To: 'Samuel Longiaru'; 'Connors, Bernie (SNB)'
Cc: 'talk-ca'
Subject: Re: [Talk-ca] Mapping cut blocks in "wooded" areas

 

Samuel wrote: "Would it be counterproductive to map cut-blocks?  Well, not
counterproductive, but maybe "differently" productive" 

 

Thanks for your thought Samuel, 

 

This is exactly what I love in this project, the possibility of being
productive differently. 

Mapping the entire planet through volunteers work could have sound
counterproductive five years ago

 

Cheers,

Daniel

  _____  

From: Samuel Longiaru [mailto:longiaru at shaw.ca] 
Sent: March-07-11 12:17
To: Connors, Bernie (SNB)
Cc: 'talk-ca'
Subject: Re: [Talk-ca] Mapping cut blocks in "wooded" areas

 

Good Morning Everyone,

Thanks for the feedback on my question about mapping cut blocks in wooded
areas.  I do appreciate it and understand the points that are being made by
Daniel, Bryan and Bernie.  I've thought a lot about this, however, and would
like to address some of the points as it touches a bit on the varied
philosophies we all bring to the project.

The arguments against mapping the cut blocks as openings in the wood cover
seem to fall along the following lines:... and I hope I am not over
simplifying or expanding too much:

1) Change is the nature of the beast.  When we map "wood" (or more
accurately, "forest" in OSM terms) it is implied that there will be logging
operations taking place within, with the result that the degree of cover is
constantly changing as is the maturity of the trees.  To try to keep up is
fruitless.  When one sees a wooded area on a map one should probably just
assume that it will be highly variable.

2) There are people who are maintaining this information to a much greater
level of detail and accuracy than OSM could ever hope to do.

3) To map them is counterproductive.

I have to say that I am not entirely convinced by these well-pointed
arguments.  

1) Yes, change is what goes on in wooded areas.  That's WHY we map them.
The value of mapping is often in what we learn by comparing maps from one
time period to another.  It's important to map so that we can track that
change.  Any map is simply a snapshot of what exists at a moment in time and
the maps themselves are outdated the moment they are made as they are
commonly based on outdated data.  To use the argument that we shouldn't map
a feature simply because it will be out-of-date tomorrow, or next week, or
next year I just don't think is convincing.  The neighborhood in which I
live in Kamloops has changed significantly even in the last two or three
years.  Houses, businesses and new streets have appeared, trails have
disappeared, streams have been diverted.  It's a struggle to keep maps
up-to-date.  But it doesn't mean that it is pointless to map the features as
best we can, with the most currently available data we have available to us.


2) The fact that better data exist elsewhere is great.  Better data  lead to
better forest management practices  and  greater sustainability.  But those
data are likely unavailable to us or would need to be heavily culled for
those relevant to OSM.  The City of Kamloops has incredibly detailed maps of
the city freely available online.  There are overlays for every curb,
parking meter and telephone pole.  Does that mean that we don't map the city
in lesser detail?  

3) Would it be counterproductive to map cut-blocks?  Well, not
counterproductive, but maybe "differently" productive.  I think one of the
beauties of this project is that we map things that are not just important
to ourselves, but maybe also to someone else.  I get a real hoot out of just
browsing through the list of official map features - things like...
power=cable_distribution_cabinet, amenity=baby_hatch (where one can
anonymously drop off a baby for adoption) and barrier=stile vs. turnstile.
These must be important and useful to someone. ???  So are cut blocks useful
to anyone who might use an OSM map or load OSM data into their GPS?  Hard to
say.  Maybe to an amateur birding group or a geocaching club or to someone
who is hurt and is looking for the nearest clearing for evacuation.  Don't
know.  Don't presume to know.    

So am I going to start mapping all the cut blocks?  Following my arguments I
probably should... but I probably won't.  I will go back and clean up the
gross errors and inconsistencies I find in the CanVec data as it relates to
natural=wood, some of which are offsets along tile boundaries and
inconsistent mapping of cuts along power lines and pipelines.  That will
probably be enough as it involves breaking and rebuilding relations which
just make me scream.  But  I'll try to clean up what we have first.

Anyway, I hope this doesn't sound like a rant because it really isn't.
While I lean towards mapping them, the arguments against are well made.  We
don't maps waves on the ocean... we accept that it will be variable.  Maybe
natural=wood is similar?  Dunno.  That's why I asked for guidance.

Truly, thanks for your responses.

Sam L.    

   


-----Original Message-----
From: Connors, Bernie (SNB) <Bernie.Connors at snb.ca
<mailto:%22Connors,%20Bernie%20%28SNB%29%22%20%3cBernie.Connors at snb.ca%3e> >
To: 'Bryan Crosby' <azubryan at gmail.com
<mailto:'Bryan%20Crosby'%20%3cazubryan at gmail.com%3e> >, 'talk-ca'
<talk-ca at openstreetmap.org
<mailto:'talk-ca'%20%3ctalk-ca at openstreetmap.org%3e> >
Subject: Re: [Talk-ca] Mapping cut blocks in "wooded" areas
Date: Mon, 07 Mar 2011 09:28:45 -0400

Bryan,

 

                I would have to agree with your argument.  I have some
knowledge of the forestry GIS that is used here in NB and it would be a
daunting task to include cut blocks in the forest.  There is more than
enough OSM work in Canada just getting the road network built it would be
counterproductive to spend a lot of time on forest cut blocks.

 

Bernie.

--

Bernie Connors, P.Eng

Service New Brunswick

(506) 444-2077

45°56'25.21"N, 66°38'53.65"W

www.snb.ca/geonb/


 

From: Bryan Crosby [mailto:azubryan at gmail.com] 
Sent: Saturday, 2011-03-05 01:58
To: 'talk-ca'
Subject: Re: [Talk-ca] Mapping cut blocks in "wooded" areas


 

I would tag it as natural=wood as I don’t feel that there is any distinction
between a 2-year old stand and a 250 year old stand in terms of being wood,
or forest.  They are merely different ages.  Licensees maintain incredibly
accurate and up-to-date maps that indicate the different openings and their
respective stages of development.  They have dedicated GIS guys that
maintain these maps as fast as techies bring it in.  I suppose, in theory,
an OSM tag could be used to indicate the stage of opening development, but
one would require the date of harvesting, the date of planting and the dates
of the silviculture surveys to accurately assess the phase.  Unless you are
a forester you won’t have access to that information and would be guessing.
I just feel that attempting to seriously map out such temporary features
accurately goes way beyond the ability of OSM (at this point, at least).

 

Bryan 

 

 

From: Samuel Longiaru [mailto:longiaru at shaw.ca] 
Sent: March-04-11 9:43 PM
To: talk-ca
Subject: Re: [Talk-ca] Mapping cut blocks in "wooded" areas


 

I very much see your point which is why I was asking for some direction.  I
guess it comes down to whether the map should reflect what we see at some
given snapshot in time, or whether it is reflecting the overall landuse
scheme.  In short, while standing in the middle of a clear-cut, would it be
more accurate that my map show that spot as wooded or not wooded?

Sam L.


-----Original Message-----
From: Bryan Crosby <azubryan at gmail.com
<mailto:Bryan%20Crosby%20%3cazubryan at gmail.com%3e> >
To: 'talk-ca' <talk-ca at openstreetmap.org
<mailto:'talk-ca'%20%3ctalk-ca at openstreetmap.org%3e> >
Subject: Re: [Talk-ca] Mapping cut blocks in "wooded" areas
Date: Fri, 04 Mar 2011 21:11:20 -0800

RE: cut-blocks

 

As someone who has spent done time as a forest technician, I strongly advise
against mapping forestry activity.  Cut block spatial data changes daily and
any images used to trace are out of date.  There are literally tens of
thousands of clear cuts in British Columbia alone and there is absolutely no
way OSM mappers would be able to keep up with changes.  Keep in mind that
most clearcuts on crown land (and in some cases, private land) are temporary
openings in various stages forest development.  A 2 year old stand is just
as much a forest as a 25 year old free-to-grow stand or a 250 year old stand
of timber.  I believe that mapping a privately held ‘Christmas’ tree farm
would be pertinent, but these are radically different from commercial
forestry openings.  

 

I would also advise extreme caution in using images to map forest
development roads unless are working on a high traffic mainline.  Many spur
roads are in various stages of deactivation.  It may look like a road from
the outdated image, but it may have been completely deactivated and
replanted.  A site inspection is the only way to be sure.  

 

Bryan

British Columbia

 

From: Daniel Begin [mailto:jfd553 at hotmail.com] 
Sent: March-04-11 8:19 PM
To: 'Samuel Longiaru'; 'talk-ca'
Subject: Re: [Talk-ca] Mapping cut blocks in "wooded" areas


 

Hi Samuel,

 

About tagging forested areas, I would use landuse=forest only if it is
obvious on the field that the area is managed/harvested, as for
landuse=orchard or landuse=vineyard. We have a lot of Christmas tree
plantations in the area and I map them as landuse=forest because it is
obvious on the imagery and on the field.  

 

If it is difficult to determine if an area is under timber lease or not,
because it looks the same, I would keep it natural=wood...

 

About Cut blocks, I would map the hole they create that wooded area.  If the
area is replanted, then some OSM contributor will remove the hole you map in
10-20 years from now! 

 

Mapping the reality is the best we can do and because the reality changes
over time, we can keep mapping !-)

 

Daniel

 

  _____  

From: Samuel Longiaru [mailto:longiaru at shaw.ca] 
Sent: March-04-11 21:45
To: talk-ca
Subject: [Talk-ca] Mapping cut blocks in "wooded" areas


 

Hi Everybody,

I've been importing CanVec mostly south of Kamloops for the past several
weeks and am going to take some time now to go back and bring stuff up to
date.  One question I have though is in regards to how to treat cut blocks
in the wooded areas.

I see according to the map features wiki, that the CanVec imported tag of
natural=wood is technically not correct, at least for here, as wood is to be
reserved only for completely reserved/unmanaged areas.  I guess most of what
I have should really be mapped as landuse=forest but I have not made the
change because what is under timber lease and what is not would be difficult
to determine.  In one sense it's all managed to some degree or other.  But
my point is rather what should be done with the cut blocks, which in some
areas constitute up to 50% or more of the forested area.
http://osm.org/go/WJ1cj_R is a typical area.  It seems improper to keep them
as wooded when they are clearly not, and yet most are replanted and will be
wooded again someday... or at least that's what they keep telling us.

I started mapping them as it truly gives a more accurate representation of
the current state of affairs on the ground... but thought I'd better get
some guidance before proceeding too far.  

Thanks,

Sam L.
Kamloops 

 
 
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