[OSM-dev] Final kinks in osmosis planet dumping

spaetz osm at sspaeth.de
Mon Sep 10 08:40:30 BST 2007

On Mon, Sep 10, 2007 at 10:41:47AM +1000, Brett Henderson wrote:
> **** 1. Different version number.

Shouldn't pose a problem IMHO

> **** 2. Lack of bound elements.
> planet.rb adds this element at the top of the file:
> <bound box="-90,-180,90,180" 
> origin="http://www.openstreetmap.org/api/0.4" />

That has been added rather recently by kleptog, to have a origin tag in there. But it worked without until recently, so it shouldn't be a problem either.

> planet.rb writes node attributes in the order id, lat, lon, timestamp.
> osmosis writes node attributes in the order id, timestamp, user, lat, lon

I wonder how much larger the resulting file becomes with user id. Given that restricting the number of decimal places in lat/lon saved us 20MB in the resulting bz2, this could be a noticable amount. Do we fulfil our attribution requirements with this, or would we have to deliver a full list of users who modified that element in order to do that? Do people think the user id is important in planet.osm?

> **** 4. Additional indenting whitespace.
> osmosis is currently using 4 space indenting, planetrb is using 2 space 
> indenting.
> I can change osmosis to use 2 space indenting if it helps reduce file 
> sizes.  Should I drop it to 1 space indenting to further reduce file size?

I'd let's compare the bzipped file size to see whether it makes a noticeable difference (I would think not, but haven't tested it).

> **** 5. Inclusion of database password on command line.
> Currently the only way to provide a database password to osmosis is on 
> the command line.  Presumably this will allow other users on the same 
> system to see the password (through the use of ps, top, etc).  If this 
> is a problem I'll have to update the database tasks to be able to read a 
> properties file containing connection information.

Mmh, every user on dev would now be able to see the password with which to connect to the db server. I would *prefer* if we could find a non-commandline variant of handling that. It is not critical by any means (I hope dev users are a responsible lot), but then...
> **** 6. Minimum of Java 1.6
> Dev currently has jdk1.5 installed preventing osmosis from running.  The 
> only code requiring 1.6 is the --bounding-polygon task.
> I have two options:
> a. Rework osmosis to only require 1.5 (either by temporarily deleting 
> the polygon task, creating a branch without the polygon task, reworking 
> the polygon task to use older features, etc).
> b. Upgrade dev to jdk 1.6.

I upgraded dev's java to 1.6 and it works fine. So this is no issue for me any more.

> **** 7. Different rounding of lat/lon coordinates.
> The java DecimalFormat appears to be rounding numbers in a slightly 
> different way to whatever planet.rb is using (sprintf?).  This only 
> occurs when a 5 has to be rounded one way or the other.  I don't think 
> this is an issue and short of writing my own decimal formatter I don't 
> think there's much I can do about this one.

I am doing a test dump on dev and will look at UTF-8 characters to see that it works out well on this box. Will let you know about the timing as well.
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