[OSM-talk] razed railways and other things that don't exist today

[Warin]

Hi,

Question:

If OSM is about mapping what exists today .. why have the tags that mean 
there is nothing left of it?


demolished:*=*
     Not existing anymore because of active removal
  removed:*=*
     Not existing anymore because of active removal (possible duplicate 
of demolished:*=*)
razed:*=*
     Not existing anymore because of active removal (duplicate of 
removed:*=*, possible duplicate of demolished:*=*)
destroyed:*=*
    Destroyed by an event other than active demolition

I think these tags would be of use in Open Historic Map (OHM) and that 
is possibly why they are in the OSM wiki?

Possibly the OSM wiki should recommend that the data with these tags be 
moved to OHM?


The argument for mapping these things from the 'old railway' people is that;

1) it does not render on the 'standard map' so it is not a problem.

2) it is used by Open Railway Maps (ORM)


My contention is;

1a) This is a problem when people try to map new things, the old things 
lead to mapping things that never existed like railway=crossing where a 
new footway/highway is also mapped over a now non existent railway line.

1b) People mapping new things may not see the old stuff on the new 
imagery .. and simply delete it, leading to edit wars.

1c) People map things like an old embankment for old railway lines .. 
right through existing roads

3) Old data should be mapped into OHM so it can be preserved .. together 
with the start and stop dates .. these 2 tags are fairly well ignored in 
OSM.

2) ORM should take current data from OSM and old data from OHM. This 
would add the start/end dates that could be used in ORM to select the 
time period. Thus those only interested in the present could have that, 
and those interested in some past date could have that.