[Talk-ca] Building Import

[Begin Daniel]

Hi all,
a first version of the cleaning tool is now functional.
At this point, the tool is built to remove extra vertices, orthogonalize building footprints (when possible) and identify overlapped geometries. Details about the application are found in Canada Building Import discussion page ...
https://wiki.openstreetmap.org/wiki/Talk:Canada_Building_Import#Quality_Assurance_details
So far, Tim has looked at the result for Montréal (Import data) and Pierre for Toronto (OSM data). I understand from their comments that the tool generally does its job well. However, both whish to see more functionality added to the application (editing automation).
Before going further, I would like to know if the community is at ease with the Pierre and Tim assessment, and is ready to go further in the import process discussion. I ask that because going further with editing automation will definitely be more complex, without any guarantee about the results.
If we agree to go further, I can try to improve the application but at least the data could be pre-processed.

Daniel

From: Nate Wessel [mailto:bike756 at gmail.com]
Sent: Thursday, March 21, 2019 13:49
To: talk-ca at openstreetmap.org
Subject: Re: [Talk-ca] Building Import


Daniel,

This is exciting news! After much talk on this list, it seems we may have some actual progress toward fixing the various data quality issues. Would you mind sharing some of your code, or a description of your workflow here or on GitHub or the like so we can take a look?

One thing you didn't mention which I think will be really critical, especially in central Toronto: We need to remove buildings from the import dataset that may already be mapped in OSM. That is, buildings that overlap with existing buildings. For this import to make any sense in Central Toronto, we need conflation to move slowly, and in smaller, more manageable steps. Buildings that are already mapped should be checked manually at a later time in batches that a skilled human can manage in less than an hour. The tasking manager as it's currently set up would have all of downtown conflated by hand in one task by a single mapper - a recipe for disaster I'm sure, given how detailed the map is in that area.

Cheers,
Nate Wessel
Jack of all trades, Master of Geography, PhD candidate in Urban Planning
NateWessel.com<http://natewessel.com>
On 3/19/19 12:58 PM, Begin Daniel wrote:
Hi all,
As mentioned a few weeks ago, I have almost completed the development of a clean-up tool for the data to be imported.
So far, it removes nonessential vertices, orthogonalizes building corners when reasonable and ensures walls' alignment within given tolerances. Building footprints that can't be processed completely are flagged accordingly, so they could be examined thoroughly at import time.
Eventually, It should be easy to remove overlapping buildings (potentially generated from a 3d mapping), but I doubt that splitting terrace into individual buildings can be done automatically.
The tool uses some parameters that need to be adjusted. I would like that those who are interested in this aspect of the import send me benchmark data that could be problematic. I will process them to adjust parameters and/or the tool, and I will send back the results to the sender for a thorough examination.
I should soon document the process in the "Canada Building Import" wiki page (in a pre-processing section).

Thought? Comments?

Daniel




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