[Tagging] better mapping for embankments / slopes

[Martin Koppenhoefer]

Currently we are mapping only one side of the embankment (I think it's the
upper side, but am not sure if the wiki says this explicitly), with the
direction. What we would IMHO need is a way to map the lower side as well
and to combine both. A closed polygon will not work I believe.

The obvious solution that comes to mind is a new relation type: in case the
upper end is mapped, draw a new way for the lower end and combine both with
a relation (possibly assigning roles like upper and lower, maybe also draw
lateral ways (ways that connect the ends of the upper and lower ways and
defines their shape) in cases they are not straight). (The type=area
relation does this)

Maybe it could also be done without the relation, simply by tagging the
upper and lower ways accordingly, and connect them at least at one of their
ends with an explicit lateral way (and respective tags). This would require
from the data user to topologically search for the embankment area in order
to be able to render it (or make other use).

What do you think, which representation is better? Are there alternatives?

Cheers,
Martin

[Volker Schmidt]

If you want to micromap slopes you should create a new key "slope" or
something similar. An embankment has two slopes. It is equivalent to dyke
or levee. The one-side embankments that are defined in the OSM wiki, are in
reality slopes and should be retagged accordingly.

Independently of the name used fo the tag I see the prblem of defining
where the slope starts, normally these are rounded features.

Post by Martin Koppenhoefer
Currently we are mapping only one side of the embankment (I think it's the
upper side, but am not sure if the wiki says this explicitly), with the
direction. What we would IMHO need is a way to map the lower side as well
and to combine both. A closed polygon will not work I believe.
The obvious solution that comes to mind is a new relation type: in case
the upper end is mapped, draw a new way for the lower end and combine both
with a relation (possibly assigning roles like upper and lower, maybe also
draw lateral ways (ways that connect the ends of the upper and lower ways
and defines their shape) in cases they are not straight). (The type=area
relation does this)
Maybe it could also be done without the relation, simply by tagging the
upper and lower ways accordingly, and connect them at least at one of their
ends with an explicit lateral way (and respective tags). This would require
from the data user to topologically search for the embankment area in order
to be able to render it (or make other use).
What do you think, which representation is better? Are there alternatives?
Cheers,
Martin
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

[Warin]

Not all embankment have 2 slopes .. nor does a 'slope' describe all of
the properties of an embankment. The same problem exists for a 'cliff'
and a 'cutting' ... and stairs that cover a large area. So use what has
been done for them as a guide.

What are the key properties of these features ...

Length - simple set as the length of the way. Cliffs are tagged as a
single way at the top of the cliff, with the right hand side being
'downwards' when facing the direction of the way.

Vertical rise - could be tagged with the height key.. this can vary over
the length of the feature (I have found this on some maps as a number in
meters ... assumed to be the maximum vertical locally rise in meters) To
accomodate teh change in vertical height .. put the height on individual
nodes?

Slope - or in OSM terms 'incline'. This in OSM is entered as a way along
the top where the slope would be minimal and not what 'we' want to
describe. ... as cliffs, cuttings and embankments are best described
this way I think incline may not be the best thing to tag? Humm stairs
are described using the incline key ... but on a way that goes up ..
leaving the top and bottom free of this. So maybe a top and bottom way
.. with a simple way from bottom to top containing the incline information?

While the 'top' and 'bottom' of natural features can be a bit fuzzy they
are features that should be mapped. Definition? Something for a
geologist? Along the lines of the line formed by the intersection of the
average slope of land before the change to the average slope of land
after the change ( the change being the cliff, embankment or cutting)?

Post by Volker Schmidt
If you want to micromap slopes you should create a new key "slope" or
something similar. An embankment has two slopes. It is equivalent to
dyke or levee. The one-side embankments that are defined in the OSM
wiki, are in reality slopes and should be retagged accordingly.
Independently of the name used fo the tag I see the prblem of defining
where the slope starts, normally these are rounded features.
On 29 November 2016 at 13:48, Martin Koppenhoefer
Currently we are mapping only one side of the embankment (I think
it's the upper side, but am not sure if the wiki says this
explicitly), with the direction. What we would IMHO need is a way
to map the lower side as well and to combine both. A closed
polygon will not work I believe.
The obvious solution that comes to mind is a new relation type: in
case the upper end is mapped, draw a new way for the lower end and
combine both with a relation (possibly assigning roles like upper
and lower, maybe also draw lateral ways (ways that connect the
ends of the upper and lower ways and defines their shape) in cases
they are not straight). (The type=area relation does this)
Maybe it could also be done without the relation, simply by
tagging the upper and lower ways accordingly, and connect them at
least at one of their ends with an explicit lateral way (and
respective tags). This would require from the data user to
topologically search for the embankment area in order to be able
to render it (or make other use).
What do you think, which representation is better? Are there alternatives?
Cheers,
Martin
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging
<https://lists.openstreetmap.org/listinfo/tagging>
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

[Volker Schmidt]

Post by Warin
Not all embankment have 2 slopes

To my understanding of the English term, an "embankment" is the equivalent
of dyke or levee and is a long, narrow man-made elevation. Therefore they
always have two slopes of opposite directions (leaving out the ends)

What Martin proposes should get a different tag name to distinguish it from
an embankment. The term "on-sided enmbankment" is used in OSM for this, but
I do not like it at all. I strongly recommend to use a different tag name.
I used "slope" as this is the term used to describe the inclined flanks of
levees (=embankments).


Length - simple set as the length of the way. Cliffs are tagged as a single
way at the top of the cliff, with the right hand side being 'downwards'
when facing the direction of the way.

Vertical rise - could be tagged with the height key.. this can vary over
the length of the feature (I have found this on some maps as a number in
meters ... assumed to be the maximum vertical locally rise in meters) To
accomodate teh change in vertical height .. put the height on individual
nodes?

Slope - or in OSM terms 'incline'. This in OSM is entered as a way along
the top where the slope would be minimal and not what 'we' want to
describe. ... as cliffs, cuttings and embankments are best described this
way I think incline may not be the best thing to tag? Humm stairs are
described using the incline key ... but on a way that goes up .. leaving
the top and bottom free of this. So maybe a top and bottom way .. with a
simple way from bottom to top containing the incline information?

While the 'top' and 'bottom' of natural features can be a bit fuzzy they
are features that should be mapped. Definition? Something for a geologist?
Along the lines of the line formed by the intersection of the average slope
of land before the change to the average slope of land after the change (
the change being the cliff, embankment or cutting)?

Post by Warin
If you want to micromap slopes you should create a new key "slope" or
something similar. An embankment has two slopes. It is equivalent to dyke
or levee. The one-side embankments that are defined in the OSM wiki, are in
reality slopes and should be retagged accordingly.
Independently of the name used fo the tag I see the prblem of defining
where the slope starts, normally these are rounded features.

Post by Martin Koppenhoefer
Currently we are mapping only one side of the embankment (I think it's
the upper side, but am not sure if the wiki says this explicitly), with the
direction. What we would IMHO need is a way to map the lower side as well
and to combine both. A closed polygon will not work I believe.
The obvious solution that comes to mind is a new relation type: in case
the upper end is mapped, draw a new way for the lower end and combine both
with a relation (possibly assigning roles like upper and lower, maybe also
draw lateral ways (ways that connect the ends of the upper and lower ways
and defines their shape) in cases they are not straight). (The type=area
relation does this)
Maybe it could also be done without the relation, simply by tagging the
upper and lower ways accordingly, and connect them at least at one of their
ends with an explicit lateral way (and respective tags). This would require
from the data user to topologically search for the embankment area in order
to be able to render it (or make other use).
What do you think, which representation is better? Are there alternatives?
Cheers,
Martin
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

_______________________________________________
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

[Kevin Kenny]

'Embankment' is frequently used for a built-up structure on a steep
hillside that keeps a road, railroad, or similar feature from sliding into
a gorge or river. See
Loading Image...
for an illustration from Wikipedia. Except for the portion crossing the
tributary stream, the road in the picture is clearly NOT banked on the
uphill side, so the embankment here is what Warin was describing as
'one-sided.'

Locally to me, this is the commonest sense of the word.

I am a native speaker of American English, and I live in terrain heavily
sculpted by the glaciers of the last Ice Age, where highway and railroad
embankments are relatively common.

Post by Volker Schmidt

Post by Warin
Not all embankment have 2 slopes

To my understanding of the English term, an "embankment" is the equivalent
of dyke or levee and is a long, narrow man-made elevation. Therefore they
always have two slopes of opposite directions (leaving out the ends)
What Martin proposes should get a different tag name to distinguish it
from an embankment. The term "on-sided enmbankment" is used in OSM for
this, but I do not like it at all. I strongly recommend to use a different
tag name. I used "slope" as this is the term used to describe the inclined
flanks of levees (=embankments).
Length - simple set as the length of the way. Cliffs are tagged as a
single way at the top of the cliff, with the right hand side being
'downwards' when facing the direction of the way.
Vertical rise - could be tagged with the height key.. this can vary over
the length of the feature (I have found this on some maps as a number in
meters ... assumed to be the maximum vertical locally rise in meters) To
accomodate teh change in vertical height .. put the height on individual
nodes?
Slope - or in OSM terms 'incline'. This in OSM is entered as a way along
the top where the slope would be minimal and not what 'we' want to
describe. ... as cliffs, cuttings and embankments are best described this
way I think incline may not be the best thing to tag? Humm stairs are
described using the incline key ... but on a way that goes up .. leaving
the top and bottom free of this. So maybe a top and bottom way .. with a
simple way from bottom to top containing the incline information?
While the 'top' and 'bottom' of natural features can be a bit fuzzy they
are features that should be mapped. Definition? Something for a geologist?
Along the lines of the line formed by the intersection of the average slope
of land before the change to the average slope of land after the change (
the change being the cliff, embankment or cutting)?

Post by Warin
If you want to micromap slopes you should create a new key "slope" or
something similar. An embankment has two slopes. It is equivalent to dyke
or levee. The one-side embankments that are defined in the OSM wiki, are in
reality slopes and should be retagged accordingly.
Independently of the name used fo the tag I see the prblem of defining
where the slope starts, normally these are rounded features.

Post by Martin Koppenhoefer
Currently we are mapping only one side of the embankment (I think it's
the upper side, but am not sure if the wiki says this explicitly), with the
direction. What we would IMHO need is a way to map the lower side as well
and to combine both. A closed polygon will not work I believe.
The obvious solution that comes to mind is a new relation type: in case
the upper end is mapped, draw a new way for the lower end and combine both
with a relation (possibly assigning roles like upper and lower, maybe also
draw lateral ways (ways that connect the ends of the upper and lower ways
and defines their shape) in cases they are not straight). (The type=area
relation does this)
Maybe it could also be done without the relation, simply by tagging the
upper and lower ways accordingly, and connect them at least at one of their
ends with an explicit lateral way (and respective tags). This would require
from the data user to topologically search for the embankment area in order
to be able to render it (or make other use).
What do you think, which representation is better? Are there
alternatives?
Cheers,
Martin
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

_______________________________________________
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

[Lorenzo "Beba" Beltrami]

It makes sense that a road embankment have only one slope.

Perhaps for a levee[1] we need a specific tagging system because a levee
has always two slopes.

I'm native of the Po Valley where levees are along every river (Volker can
confirm it ;) ).
A levee for flood prevention could be simple[2] but even a wide and complex
feature[3] to map.

Lorenzo

[1] https://en.wikipedia.org/wiki/Levee#River_flood_prevention
[2]
Loading Image...
[3]
Loading Image...

Post by Kevin Kenny
'Embankment' is frequently used for a built-up structure on a steep
hillside that keeps a road, railroad, or similar feature from sliding into
a gorge or river. See https://en.wikipedia.org/wiki/
Embankment_%28transportation%29#/media/File:Embankment_1_%28PSF%29.png
for an illustration from Wikipedia. Except for the portion crossing the
tributary stream, the road in the picture is clearly NOT banked on the
uphill side, so the embankment here is what Warin was describing as
'one-sided.'
Locally to me, this is the commonest sense of the word.
I am a native speaker of American English, and I live in terrain heavily
sculpted by the glaciers of the last Ice Age, where highway and railroad
embankments are relatively common.

Post by Volker Schmidt

Post by Warin
Not all embankment have 2 slopes

To my understanding of the English term, an "embankment" is the
equivalent of dyke or levee and is a long, narrow man-made elevation.
Therefore they always have two slopes of opposite directions (leaving out
the ends)
What Martin proposes should get a different tag name to distinguish it
from an embankment. The term "on-sided enmbankment" is used in OSM for
this, but I do not like it at all. I strongly recommend to use a different
tag name. I used "slope" as this is the term used to describe the inclined
flanks of levees (=embankments).
Length - simple set as the length of the way. Cliffs are tagged as a
single way at the top of the cliff, with the right hand side being
'downwards' when facing the direction of the way.
Vertical rise - could be tagged with the height key.. this can vary over
the length of the feature (I have found this on some maps as a number in
meters ... assumed to be the maximum vertical locally rise in meters) To
accomodate teh change in vertical height .. put the height on individual
nodes?
Slope - or in OSM terms 'incline'. This in OSM is entered as a way along
the top where the slope would be minimal and not what 'we' want to
describe. ... as cliffs, cuttings and embankments are best described this
way I think incline may not be the best thing to tag? Humm stairs are
described using the incline key ... but on a way that goes up .. leaving
the top and bottom free of this. So maybe a top and bottom way .. with a
simple way from bottom to top containing the incline information?
While the 'top' and 'bottom' of natural features can be a bit fuzzy they
are features that should be mapped. Definition? Something for a geologist?
Along the lines of the line formed by the intersection of the average slope
of land before the change to the average slope of land after the change (
the change being the cliff, embankment or cutting)?

Post by Warin
If you want to micromap slopes you should create a new key "slope" or
something similar. An embankment has two slopes. It is equivalent to dyke
or levee. The one-side embankments that are defined in the OSM wiki, are in
reality slopes and should be retagged accordingly.
Independently of the name used fo the tag I see the prblem of defining
where the slope starts, normally these are rounded features.
On 29 November 2016 at 13:48, Martin Koppenhoefer <

Post by Martin Koppenhoefer
Currently we are mapping only one side of the embankment (I think it's
the upper side, but am not sure if the wiki says this explicitly), with the
direction. What we would IMHO need is a way to map the lower side as well
and to combine both. A closed polygon will not work I believe.
The obvious solution that comes to mind is a new relation type: in case
the upper end is mapped, draw a new way for the lower end and combine both
with a relation (possibly assigning roles like upper and lower, maybe also
draw lateral ways (ways that connect the ends of the upper and lower ways
and defines their shape) in cases they are not straight). (The type=area
relation does this)
Maybe it could also be done without the relation, simply by tagging the
upper and lower ways accordingly, and connect them at least at one of their
ends with an explicit lateral way (and respective tags). This would require
from the data user to topologically search for the embankment area in order
to be able to render it (or make other use).
What do you think, which representation is better? Are there alternatives?
Cheers,
Martin
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

_______________________________________________
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

[Warin]

I would hope that a scheme can be had that is one sided - and the same
for cliff, embankment, cutting etc.

As such it should be one sided. After all another side could have a
different slope/area. A single sided scheme could be used for 2 sided or
multi sided structures by many separate one sided OSM entries, as many
entries as required to represent the structure. In this way the name of
the structure has less relevance ... when does an embankment become a
cutting? A cutting a cliff? If the result is the same .. then it does
not really matter what it it called, avoids arguments of things like
masts vs tower, monument vs memorial.

One rendering, not OSM based, has cliffs in pink, the top with spikes
pointing downwards and the vertical rise stated as a number in meters.

Post by Lorenzo "Beba" Beltrami
It makes sense that a road embankment have only one slope.
Perhaps for a levee[1] we need a specific tagging system because a
levee has always two slopes.
I'm native of the Po Valley where levees are along every river (Volker
can confirm it ;) ).
A levee for flood prevention could be simple[2] but even a wide and
complex feature[3] to map.
Lorenzo
[1] https://en.wikipedia.org/wiki/Levee#River_flood_prevention
<https://en.wikipedia.org/wiki/Levee#River_flood_prevention>
[2]
http://www.navecorsara.it/wp/wp-content/uploads/2010/01/Stirone_argine_1-580x435.jpg
[3]
http://bur.regione.veneto.it/resourcegallery/photos/465_Guarda%20Veneta_ro_Panorama%20con%20argine.jpg
'Embankment' is frequently used for a built-up structure on a
steep hillside that keeps a road, railroad, or similar feature
from sliding into a gorge or river. See
https://en.wikipedia.org/wiki/Embankment_%28transportation%29#/media/File:Embankment_1_%28PSF%29.png
<https://en.wikipedia.org/wiki/Embankment_%28transportation%29#/media/File:Embankment_1_%28PSF%29.png>
for an illustration from Wikipedia. Except for the portion
crossing the tributary stream, the road in the picture is clearly
NOT banked on the uphill side, so the embankment here is what
Warin was describing as 'one-sided.'
Locally to me, this is the commonest sense of the word.
I am a native speaker of American English, and I live in terrain
heavily sculpted by the glaciers of the last Ice Age, where
highway and railroad embankments are relatively common.
Not all embankment have 2 slopes
To my understanding of the English term, an "embankment" is
the equivalent of dyke or levee and is a long, narrow man-made
elevation. Therefore they always have two slopes of opposite
directions (leaving out the ends)
What Martin proposes should get a different tag name to
distinguish it from an embankment. The term "on-sided
enmbankment" is used in OSM for this, but I do not like it at
all. I strongly recommend to use a different tag name. I used
"slope" as this is the term used to describe the inclined
flanks of levees (=embankments).
Length - simple set as the length of the way. Cliffs are
tagged as a single way at the top of the cliff, with the right
hand side being 'downwards' when facing the direction of the way.
Vertical rise - could be tagged with the height key.. this can
vary over the length of the feature (I have found this on some
maps as a number in meters ... assumed to be the maximum
vertical locally rise in meters) To accomodate teh change in
vertical height .. put the height on individual nodes?
Slope - or in OSM terms 'incline'. This in OSM is entered as a
way along the top where the slope would be minimal and not
what 'we' want to describe. ... as cliffs, cuttings and
embankments are best described this way I think incline may
not be the best thing to tag? Humm stairs are described using
the incline key ... but on a way that goes up .. leaving the
top and bottom free of this. So maybe a top and bottom way ..
with a simple way from bottom to top containing the incline
information?
While the 'top' and 'bottom' of natural features can be a bit
fuzzy they are features that should be mapped. Definition?
Something for a geologist? Along the lines of the line formed
by the intersection of the average slope of land before the
change to the average slope of land after the change ( the
change being the cliff, embankment or cutting)?

Post by Volker Schmidt
If you want to micromap slopes you should create a new
key "slope" or something similar. An embankment has two
slopes. It is equivalent to dyke or levee. The one-side
embankments that are defined in the OSM wiki, are in
reality slopes and should be retagged accordingly.
Independently of the name used fo the tag I see the
prblem of defining where the slope starts, normally these
are rounded features.
On 29 November 2016 at 13:48, Martin Koppenhoefer
Currently we are mapping only one side of the
embankment (I think it's the upper side, but am not
sure if the wiki says this explicitly), with the
direction. What we would IMHO need is a way to map
the lower side as well and to combine both. A closed
polygon will not work I believe.
The obvious solution that comes to mind is a new
relation type: in case the upper end is mapped, draw
a new way for the lower end and combine both with a
relation (possibly assigning roles like upper and
lower, maybe also draw lateral ways (ways that
connect the ends of the upper and lower ways and
defines their shape) in cases they are not straight).
(The type=area relation does this)
Maybe it could also be done without the relation,
simply by tagging the upper and lower ways
accordingly, and connect them at least at one of
their ends with an explicit lateral way (and
respective tags). This would require from the data
user to topologically search for the embankment area
in order to be able to render it (or make other use).
What do you think, which representation is better?
Are there alternatives?
Cheers,
Martin
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging
<https://lists.openstreetmap.org/listinfo/tagging>
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging
<https://lists.openstreetmap.org/listinfo/tagging>

_______________________________________________ Tagging
https://lists.openstreetmap.org/listinfo/tagging
<https://lists.openstreetmap.org/listinfo/tagging>
_______________________________________________ Tagging
https://lists.openstreetmap.org/listinfo/tagging
<https://lists.openstreetmap.org/listinfo/tagging>
_______________________________________________ Tagging mailing
https://lists.openstreetmap.org/listinfo/tagging
<https://lists.openstreetmap.org/listinfo/tagging>
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

[Kevin Kenny]

I render the things that OSM shows as cliffs, because sometimes surprises
lurk between the contour lines. Otherwise, when I care, on my own maps I
render elevation contours (and hence have no use for the cliff height in
the data base). In a spot like
https://kbk.is-a-geek.net/catskills/test3.html?la=42.1876&lo=-74.0397&z=14,
it's pretty obvious that there are cliffs about.

I do like the idea of having some sort of object for cuts and fills,
because they're important features that often aren't in the elevation
databases. Highway and rail embankments would kind of come along for the
ride.

I would hope that a scheme can be had that is one sided - and the same for
cliff, embankment, cutting etc.
As such it should be one sided. After all another side could have a
different slope/area. A single sided scheme could be used for 2 sided or
multi sided structures by many separate one sided OSM entries, as many
entries as required to represent the structure. In this way the name of the
structure has less relevance ... when does an embankment become a cutting?
A cutting a cliff? If the result is the same .. then it does not really
matter what it it called, avoids arguments of things like masts vs tower,
monument vs memorial.
One rendering, not OSM based, has cliffs in pink, the top with spikes
pointing downwards and the vertical rise stated as a number in meters.
It makes sense that a road embankment have only one slope.
Perhaps for a levee[1] we need a specific tagging system because a levee
has always two slopes.
I'm native of the Po Valley where levees are along every river (Volker can
confirm it ;) ).
A levee for flood prevention could be simple[2] but even a wide and
complex feature[3] to map.
Lorenzo
[1] https://en.wikipedia.org/wiki/Levee#River_flood_prevention
[2] http://www.navecorsara.it/wp/wp-content/uploads/2010/01/
Stirone_argine_1-580x435.jpg
[3] http://bur.regione.veneto.it/resourcegallery/photos/465_
Guarda%20Veneta_ro_Panorama%20con%20argine.jpg

Post by Kevin Kenny
'Embankment' is frequently used for a built-up structure on a steep
hillside that keeps a road, railroad, or similar feature from sliding into
a gorge or river. See https://en.wikipedia.org/wiki/
Embankment_%28transportation%29#/media/File:Embankment_1_%28PSF%29.png
for an illustration from Wikipedia. Except for the portion crossing the
tributary stream, the road in the picture is clearly NOT banked on the
uphill side, so the embankment here is what Warin was describing as
'one-sided.'
Locally to me, this is the commonest sense of the word.
I am a native speaker of American English, and I live in terrain heavily
sculpted by the glaciers of the last Ice Age, where highway and railroad
embankments are relatively common.

Post by Volker Schmidt

Post by Warin
Not all embankment have 2 slopes

To my understanding of the English term, an "embankment" is the
equivalent of dyke or levee and is a long, narrow man-made elevation.
Therefore they always have two slopes of opposite directions (leaving out
the ends)
What Martin proposes should get a different tag name to distinguish it
from an embankment. The term "on-sided enmbankment" is used in OSM for
this, but I do not like it at all. I strongly recommend to use a different
tag name. I used "slope" as this is the term used to describe the inclined
flanks of levees (=embankments).
Length - simple set as the length of the way. Cliffs are tagged as a
single way at the top of the cliff, with the right hand side being
'downwards' when facing the direction of the way.
Vertical rise - could be tagged with the height key.. this can vary over
the length of the feature (I have found this on some maps as a number in
meters ... assumed to be the maximum vertical locally rise in meters) To
accomodate teh change in vertical height .. put the height on individual
nodes?
Slope - or in OSM terms 'incline'. This in OSM is entered as a way along
the top where the slope would be minimal and not what 'we' want to
describe. ... as cliffs, cuttings and embankments are best described this
way I think incline may not be the best thing to tag? Humm stairs are
described using the incline key ... but on a way that goes up .. leaving
the top and bottom free of this. So maybe a top and bottom way .. with a
simple way from bottom to top containing the incline information?
While the 'top' and 'bottom' of natural features can be a bit fuzzy they
are features that should be mapped. Definition? Something for a geologist?
Along the lines of the line formed by the intersection of the average slope
of land before the change to the average slope of land after the change (
the change being the cliff, embankment or cutting)?

Post by Warin
If you want to micromap slopes you should create a new key "slope" or
something similar. An embankment has two slopes. It is equivalent to dyke
or levee. The one-side embankments that are defined in the OSM wiki, are in
reality slopes and should be retagged accordingly.
Independently of the name used fo the tag I see the prblem of defining
where the slope starts, normally these are rounded features.
On 29 November 2016 at 13:48, Martin Koppenhoefer <

Post by Martin Koppenhoefer
Currently we are mapping only one side of the embankment (I think it's
the upper side, but am not sure if the wiki says this explicitly), with the
direction. What we would IMHO need is a way to map the lower side as well
and to combine both. A closed polygon will not work I believe.
The obvious solution that comes to mind is a new relation type: in
case the upper end is mapped, draw a new way for the lower end and combine
both with a relation (possibly assigning roles like upper and lower, maybe
also draw lateral ways (ways that connect the ends of the upper and lower
ways and defines their shape) in cases they are not straight). (The
type=area relation does this)
Maybe it could also be done without the relation, simply by tagging
the upper and lower ways accordingly, and connect them at least at one of
their ends with an explicit lateral way (and respective tags). This would
require from the data user to topologically search for the embankment area
in order to be able to render it (or make other use).
What do you think, which representation is better? Are there alternatives?
Cheers,
Martin
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

_______________________________________________
_______________________________________________ Tagging mailing list
g/listinfo/tagging

_______________________________________________ Tagging mailing list
g/listinfo/tagging

_______________________________________________ Tagging mailing list
g/listinfo/tagging

_______________________________________________
_______________________________________________
Tagging mailing list
https://lists.openstreetmap.org/listinfo/tagging

[John Willis]

Javbw

'Embankment' is frequently used for a built-up structure on a steep hillside that keeps a road, railroad, or similar feature from sliding into a gorge or river.

So a retaining wall (or reinforced "retaining slope"?) is when an embankment / cutting is covered with a man made structure, like concrete, bricks,rocks, or a soil-nail wall?

So a road in a "cutting" could be surrounded by an embankment or a retaining wall?

Here are some terraced embankments cut into the ground. They are bare rock. The motorway here is 40-50m below ground level - they removed an entire mountain to make this deep cutting. The two sides used to be connected by a single gentle slope before.

https://goo.gl/maps/8X3uiCNq1JH2

In my home town in Japan they cut away a hillside, Forming 3 terraced embankments, to widen a train line going into town.

http://www.openstreetmap.org/#map=18/36.41246/139.32270

If you are going to have relations of top and bottom, I think you also need "side" - often the ends are an angle, ending up looking like a trapezoid.

Javbw

[Martin Koppenhoefer]

Although it can be interesting how to map embankment properties on other
objects like roads or railroads (where the discussion led in the meantime),
this discussion started as a question how to map embankments on their own,
as features. I am interested in providing the data needed to create a map
signature like the embankments/slopes visible here (they use a similar
signature than OSM-Carto for embankments):

Loading Image...

Properties like length and slope are not suitable for irregular shapes
(=most embankments, at least at their ends), i.e. the length of the slope
changes. I believe we do need an upper and a lower way and put them somehow
together, but I am not sure which way is better (other ways or a relation).

Cheers,
Martin

[Volker Schmidt]

Post by Kevin Kenny
'Embankment' is frequently used for a built-up structure on a steep
hillside that keeps a road, railroad, or similar feature from sliding into
a gorge or river. See https://en.wikipedia.org/wiki/
Embankment_%28transportation%29#/media/File:Embankment_1_%28PSF%29.png
for an illustration from Wikipedia. Except for the portion crossing the
tributary stream, the road in the picture is clearly NOT banked on the
uphill side, so the embankment here is what Warin was describing as
'one-sided.'

I would tag the structures in the illustration as "retaining_wall" in OSM.

I guess the contradicting statements may stem from differences between
British and US English (I am German myself with a British-English bias as I
lived in the UK for many years)

BTW there is a similar ambiguity regarding the definition of "pier" between
US and British English.

It's important to create tagging that is not ambiguous so that the data
users can get it right.
I am familiar with the style in Martin's example, as it's used in many maps
in Germany, and I agree with him that we shpuld be able to tag such
features correctly in OSM

[Martin Koppenhoefer]

Post by Volker Schmidt
I would tag the structures in the illustration as "retaining_wall" in OSM.

+1, but there's also an embankment. And there are similar cases without the
retaining wall, so it's of course completely possible to have an embankment
on one side only.

Cheers,
Martin