SetTag() not working ?

[etienneJr]

I can't make SetTag() to work... Could you please confirm that it should work ?
I even tried:

function relation_postscan_function()
	SetTag("name", "test")
end

but it doesn't overwrite any name.

[systemed]

Yes, it should work - I use it in my tiles for cycle.travel and it seems to be functioning fine. Can you explain how you're then reading the name tag?

[etienneJr]

OK I will retry soon and let you know. Can SetTag set a new tag or only overwrite an existing tag?

[etienneJr]

I tried again and could not make it work.

Here is somehow what I did:

1. I accepted route relations for a specific set of values in routeClasses (outdoor relations)

function relation_scan_function()
	local relType = Find("type")
	local route = Find("route")
	if relType == "route" and (routeClasses[route]) then
		Accept()
	end
end

2. I wrote a relation_postscan_function to overwrite name and route, and set a new tag

function relation_postscan_function()
	if Find("type") == "route" then
		print("will modify: "..Find("route").." / "..Find("name"))
		SetTag("route", "canoe")
		SetTag("name", "niagara falls")
		SetTag("newtag", "new value")
	end
end

3. In relation_function() I tried to read these tags either with Find() or with SetNameAttributes() for name

function relation_function()
	local relType = Find("type")
	local route = Find("route")
 	if relType == "route" and routeClasses[route] then
		  Layer("route", false)
		  Attribute("class", routeClasses[route])
		  Attribute("subclass", route)
		  SetOsmTypeAttribute()
		  SetNameAttributes()
		  Attribute("directname",   Find("name"))
		  Attribute("newtag",   Find("newtag"))
	end
end

But I still get the original values:
(I should have class=water and subclass=canoe after overwriting as route=canoe)

4. I also tried in way_function(), with a loop on relations, and reading the value with FindInRelation() :

function way_function()
	if it is a highway/waterway with at least 1 outdoor route in parent relations then
		Layer("route", false)
		SetOsmTypeAttribute()
		RestartRelations()
		local i=0
		while true do
			local rel = NextRelation()
			if not rel then break end
			i = i + 1
			Attribute("relation_route_"..i, FindInRelation("route"))
			Attribute("relation_name_"..i, FindInRelation("name"))
			Attribute("relation_newtag_"..i, FindInRelation("newtag"))
		end
	end
end

But once again I still get the original values:

The way used for the captures is way/117499718.

Have I misunderstood something about how to use SetTag()?

[etienneJr]

Update: I checked the relation listed by the print("will modify: "..Find("route").." / "..Find("name")) and in fact it worked for them. So it is as if all relations where not modified during relation_postscan_function(). I am continuing to investigate.

[etienneJr]

That's exactly the problem, on my extract (alsace.osm.pbf):

• relation_scan_function() accepts 3095 outdoor route relations
• relation_postscan_function() modifies only 91 of them (always the same ones at each run)

even if I use the exact same test in both functions to identify the wanted outdoor route relations:
if relType == "route" and routeClasses[route] then

[etienneJr]

The issue happens using Find() in relation_postscan_function() : most of the time the tags cannot be read, but sometimes they can.
For example if I set:

function relation_postscan_function()
	local relType = Find("type")
	local route = Find("route")
	print("reading | "..Id().." | "..relType.." | "..route.." | "..Find("name"))
end

the output shows that even type is not found most of the time:

...
reading | 4630050 | boundary |  | Strasbourg
reading | 4631353 |  |  | 
reading | 4638554 |  |  | 
reading | 4638555 |  |  | 
reading | 4638556 |  |  | 
reading | 4660074 |  |  | 
reading | 4660075 |  |  | 
reading | 4750473 |  |  | 
reading | 5397874 | route | bicycle | Grüne Straße - Route Verte
reading | 6008190 | boundary |  | Goldscheuer
reading | 6366400 |  |  | 
reading | 7089093 | boundary |  | Meißenheim
reading | 8812709 |  |  | 
reading | 8812718 |  |  | 
reading | 9485492 | route | bicycle | EuroVelo 5 - Via Romea Francigena - part Germany 2
reading | 10180633 |  |  | 
reading | 10180634 | boundary |  | Auenheim
reading | 10180635 |  |  | 
reading | 10180636 |  |  | 
reading | 10180637 |  |  | 
reading | 10180638 | boundary |  | Leutesheim
reading | 10547174 | route | hiking | Les Chemins de la Mémoire
reading | 10796782 | route | hiking | Interregio-Wanderweg
reading | 10978514 | route | bicycle | EuroVelo 15 - Rhine Route - connection parts Switzerland and France
reading | 11148820 | route | hiking | Sentier interregio - Wanderweg - Losange rouge
reading | 11776010 | route | hiking | Circuit de la Mémoire
reading | 11777304 |  |  | 
reading | 11777312 |  |  | 
reading | 11825998 |  |  | 
reading | 12611328 | route | hiking | Circuit de la mémoire d'Ammertzwiller
reading | 12753925 |  |  | 
reading | 12753929 |  |  | 
reading | 12753931 |  |  | 
reading | 12753933 |  |  | 
reading | 12753935 | route | bicycle | 
reading | 12882345 | route | hiking | Interegio-Wanderweg
reading | 12914396 |  |  | 
reading | 12979767 |  |  | 
reading | 13179844 |  |  | 
reading | 13179846 |  |  | 
reading | 13342610 | route | hiking | Circuit Mémoire de la guerre 14-18
reading | 13391970 | route | hiking | Interregio-Wanderweg (deutscher Abschnitt)
reading | 13436818 |  |  | 
reading | 13436824 |  |  | 
reading | 13436825 |  |  | 
reading | 13446804 |  |  | 

...