[talk-au] Microsoft Australian building footprints

[Daniel O'Connor]

Looks like my other message didn't go through.

Agree re the slight rotational issues; and it being at about the level of a
new-intermediate contributor from the samples around Adelaide I managed to
look at.

I found sometimes, it would mistake bright concrete as part of a building
footprint.

Because of the simple way I split the files up, I've only got sporadic
coverage - a few buildings per street from my 10% sample. I'm not sure if
the original file is sorted by longitude/latitude in any way; or if the
model simply missed many of these. @Andrew Harvey <andrew.harvey4 at gmail.com> -
can you shed some light on this?

On Wed, Oct 21, 2020 at 12:30 PM Andrew Harvey <andrew.harvey4 at gmail.com>
wrote:

> Also buildings which are touching like a shop fronts are just one polygon,
> but I don't think you'd ever be able to do this too reliably without a
> survey anyway. Even if there is a small gap between buildings eg a garage
> and residence sometimes it will join them into a single polygon.
>
> What I feel it does do well is actually identify buildings, I haven't
> found any false positives, only a few false negatives where a building is
> hidden under dense tree coverage.
>
> On Wed, 21 Oct 2020 at 12:52, Andrew Harvey <andrew.harvey4 at gmail.com>
> wrote:
>
>> On Tue, 20 Oct 2020 at 21:20, Simon Poole <simon at poole.ch> wrote:
>>
>>> Just as a comment: there is nothing so time consuming as fixing badly
>>> mapped buildings (essentially drawing them from scratch is nearly always
>>> faster), I would only import building outlines that are at a quality level
>>> that you would not want to change them except if the building itself has
>>> been modified.
>>>
>>
>> I took a look at these building footprints from Microsoft in Sydney,
>> where we have high resolution aerial imagery with usually pretty good
>> positional accuracy and orthorectification.
>>
>> The MS buildings aren't as good as hand tracing would be, but better than
>> some of the worst mapping done through the HOT tasking manager building
>> tracing projects.
>>
>> Compared to the DCS aerial imagery the alignment (rotation) is usually a
>> fair bit off, but "good enough" basic footprints, the shape is just okay,
>> not great, not terrible.
>>
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