[Imports] Sardinia Regional Dataset Building Import: second proposal

Leonardo Frassetto kinetocore86 at gmail.com
Mon Mar 24 23:57:53 UTC 2014


Hi,

i'm writing here to request some feedback on an updated import proposal for
Sardinia. The original proposal was here:

https://lists.openstreetmap.org/pipermail/imports/2013-November/002370.html

This database contains a lot of useful information that can be used to
improve the map of Sardinia, like streets, landuses, housenumbers and
almost all the buildings on the island. The data goes between 1994 and 2009
and in the first phase we will import the buildings (if all goes well we
could go further with the rest of the data but this proposal is ONLY for
buildings).

The data is licensed under IODL 2.0 that is ODBL compatible (
http://www.sardegnageoportale.it/disclaimer.html).

Data is here:
http://www.sardegnageoportale.it/index.php?xsl=1598&s=140641&v=2&c=8831&t=1

We discussed a lot on ML about a semi-mechanic import, using a translator
as shp-to-osm and a rule files but after many tries and tweaking, still the
converted data was too much error filled and quite confused for tagging.
Also we discovered that many of the features covered in the data table on
the official pdf manual aren't present at all on the shp data, making us
wasting time searching for an appropriate tag or thinking for a possible
new tag scheme. It was decided to scrap completely the idea of a mechanical
import and goes for a complete manual check/cut/tag workflow that i'll
describe now. The workflow will be this:

On the main file (that is a HUGE shp file, 300+ MB, converted to WGS84),
every polygon has some attibutes as numbers that is translated on the pdf
manual table with the corresponding feature ex. 0010 on a polygon means a
school building (so building=school) and 00101 on an area means the
corresponding area of the school (so amenity=school). Using QGIS and the
filter option we select for example all the polygon with one number and
save that selection as a separate file. Then we open that file on JOSM +
opendata plugin and we do a manual assigned tagging and run the validator
to fix possible errors like duplicated nodes and so on. This "clean" file
will be saved as .osm. We will do this process to all the possible number
selection, so we create a clean file for every single type of buildings. We
will merge back all the data, doing a validator check every layer merged
until we have back the original SHP file converted into an .osm file that
has 0 error and all correctly tagged. This will be the first step.

The second step is cut this big file into smaller chucks of data, that can
be easily checked by importers and is not so big that can be too heavy to
work with on JOSM. We will use the an OSM boundaries service (
http://osm.wno-edv-service.de:8080/boundaries/) to download the boundaries
of a single city/town and use it as an "area selection tool " on the
original big .osm, selecting all the buildings inside and saving it as
TOWNNAME.osm that will be sent to the importer for the final check before
the upload.

The imported will do the final check that will be check for existing data,
integrate it with the import data keeping in mind that he must contact the
original mapper for discussing every possible modify/delete on his data, do
a final validation check and then upload it with the appropriate source tag
on the upload window on JOSM.

Data is already well aligned against the italian PCN2012 aerial image, that
is proved many times as a good standard for alignment, much better than
Bing images. Again the final importer will check the data to see if there
are any missing building and consider to add them on the import data. Same
thing will be for demolished building that will be deleted before the
import. Using such smaller .osm files helps the importer on the task of
visual check between photo and data.

Here is the data imported:
-Houses
-Industrial buildings
-Public building (townshall, police, schools, hospitals, libraries), area +
building associated to it.
-Churches + cementery buildings and area.
-Smaller monuments
-Sport centers + pitch + sport if specified on the original shp file.

Luckly all of these type of building have a specific, widespread used,
possible tag to assign them (using the presets on JOSM we can cover all of
them, without the need to create new ones).

We have already a wiki import page (
http://wiki.openstreetmap.org/wiki/Sardegna/Import/Edificato) were we will
keep track of the imported data with all the changesets. Please ignore the
first part with the old rules test, it will be deleted. We are writing the
manual rules and we will add them to the page very soon. We will start with
the first 60 town heavily hitted by the cyclone (first table) then we will
move to the others.

We think that with smaller steps instead of a big import, the quality of
the import can be much more consistent.

Any concern?

Regards

Leonardo (OSM user: DarkSwan_Import)
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