[HOT] HOTOSM #699: About identification of plantations (HOTOSM #699: About identification of plantations in Africa (as for cassava, manioc)

S Volk svolk2 at hotmail.com
Wed Oct 22 06:58:33 UTC 2014


Hi Blake,sorry, while struggling to find the emails you mentioned I forgot to answer you (I guess I was not receiving because I had selected digests).
As I answered before to Charlotte:
Yes, that area in http://www.openstreetmap.org/edit?editor=id&#map=19/8.83837/-12.04526
actually is of manioc (cassava). Both green(new plants or grass coverture in the holes, it's not ) and brown(picked or dry remains) rounded shapes of 1-1,5m, as I've wrote in the post.I would map it together since it's one same field, only that plantations are managed seasonally from side to side in the same uncovered field.Beside it there are planted palm orchard (it's in more regular rows, so it's different from irregular palm woods).I've tagged it by this way (there is still more to do in the area):http://www.openstreetmap.org/edit?editor=id&#map=18/8.83778/-12.04529- - -It's manioc/cassava land for sure:
-The more green rounded shapes show some shadow (to the same side of palms, so they are not remain holes in the ground), it should be plants in growing or adults.-The brown/dark rounded shapes should be only with soil or rotten remains of the plants (since only the roots are taken and the remains left in the same place; stem and leaves are toxic, some varieties very toxic).They may use it one year planted in one side, the other year change to the other side to avoid soil be exhausted.
But take a look at this for example:http://www.openstreetmap.org/edit?editor=id&#map=19/8.83944/-12.05939
You can see 3 green areas of manioc with three little different shapes (in Brazil, time between planting and picking manioc roots usually takes 1 to 1.5 year, but may take 6 months to 3 years):1) above, one rounded with small shadows, max.1m indicating new individuals in growth;2) below, one rounded with a little bigger shadows, a little more spaced (some individuals may have been already taken), around 1.5m indicating grown individuals;3) in the middle, the other rounded, very shallow, with almost no shadow, probably recent remains or new grass, indicating probably seasonal renewal of soil.The growing plants are distant from the adults to make it easier to manage both.
And palms there are 3 to 4 times larger, top with 5 to 8m diameter, long shadows.
Nigth time here. Not extending discussion for too long, but for me it's also one more example of manioc/cassava land.Better if someone else could confirm.It's the 2nd major production and 1st in tons, it's everywhere:https://en.wikipedia.org/wiki/Agriculture_in_Sierra_Leone
Rice is the 1st, but I don't know how to find it (perhaps only by color), so it may be in wetlands but not visible.
Here in Brazil both are widespread too.
Regards,Sergio



> Date: Tue, 21 Oct 2014 14:05:23 -0400
> From: bgirardot at gmail.com
> To: svolk2 at hotmail.com
> CC: hebolz at web.de
> Subject: Re: [HOT] HOTOSM #699: About identification of plantations (HOTOSM #699: About identification of plantations in Africa (as for cassava, manioc)
> 
> Hi Sergio,
> 
> We do not get copies of emails we send to the list, that is a "feature" 
> that I do not like either :(
> 
> Your follow up email to the list did get through to the list and the 
> example was great.
> 
> Did you happen to see email to the list with the subject: "[HOT] 
> cultivated areas in ETC sections?"
> 
> That looks a lot like cassava, what do you think?
> 
> Cheers,
> Blake
> 
> 
> 
> On 10/21/2014 1:58 PM, S Volk wrote:
> > Hi Blake and Henning, thanks.
> > I dont know if I send it well to hot at openstreetmap.org, because I can't
> > find the post there.
> > So I send this post below to you if it this would be useful.
> > Regards from Brazil,
> > Sergio.
> >
> > - - -
> > Some more about Africa plantations:
> >
> > Sometimes images shows cassava plantations like rounded light green
> > patterns, planted in not very regular rows (new plants).
> > Sometimes shows only brown rounded holes, but in the exact place where
> > there were plants that were already picked.
> > It only changes from sides to sides of same uncovered lands seasonally.
> > Anyway mostly it will be planted again soon, so its allotments usually
> > are permanent.
> > So it keeps being the same farmland landcover.
> >
> > Since it's planted in small strips or areas (once it's a kind of manual
> > plantation by few individuals, usually not large areas managed by
> > machines), they are sometimes isolated, sometimes following river
> > margins or wetland.
> >
> > Intending not to complicate too much, I think it will be more useful to
> > map it continuously when brown and green areas are together, since being
> > the same seasonal plantation area (not in many disconnected strips, I
> > did it before, but I think it's unnecessary perfectionism). Only when
> > it's not disconnected by remarkable different features as portions of
> > forest or rivers or non-used grassland, it may be mapped continuously).
> >
> > Paths can be found going though it by many ways. Plantation borders
> > usually almost sure are ways for paths, if found straight paterns.
> >
> > Also, I think it's better to tag cassava plantation as farmland (not
> > orchard, since orchard is more propper for permanent plants, that are
> > not removed in the harvest, like apple trees, pepper, etc).
> > Cassava plant is entirely removed, since it is a tuberous root.
> > In this area can be seen both green and brown areas of cassava planted
> > and removed:
> >
> > http://www.openstreetmap.org/edit?editor=id&#map=18/8.78502/-12.00690
> > <http://www.openstreetmap.org/edit?editor=id&%20#map=18/8.78502/-12.00690>
> >
> > In that area can be seen also a plantation of palms, recognized by its
> > long leaves and some regular pattern, not being random. Most times I see
> > it tagged as forest. Few times as orchard. So I followed tagging as
> > forest (Wood only for natural groups). But now I guess, if to be more
> > precise, it would be more proper for "orchard" when palms are found
> > planted in regular patterns, since it's for picking its fruits (not
> > mostly for cut it to use its wood, as landuse tag for forest). But guess
> > it's not worth for changing all done around Africa. It makes no much
> > remarkable difference for practice, and there are still much more
> > unidentified features to be done.
> >
> > Also about Sierra Leone plantations:
> > https://en.wikipedia.org/wiki/Agriculture_in_Sierra_Leone
> >
> > Regards, Sergio. Brazil.
 		 	   		  
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