[Qgis-user] manual classification tool?

[Raymond Nijssen]

On 28-05-2020 13:30, Nicolas Cadieux wrote:
> Hi,

Hi Nicolas, thanks for pointing this out!

> 
> I see many people have responded exactly to your question so I have a question for you. I am playing the devil’s advocate.  What are your classification?  Can any of this be classified any other way than manually? You could save time if you could preclassify building and only check the results manually?  Can size, shape, or colour help?  Can you use another data base like a city map or sensor data help?  Can you use satellite images to do some preclassification?  Have you thought of using AI with aerial photography?

Yes we have been thinking of automating this, but we don't think it is 
possible. We are interested in the roof construction material and in 
case of certain material, if the roof is damaged or not.

As we are not interested in overall statistics but in the actual roof 
state of houses (cause those people might get money to fix their roofs) 
we will need to manually check them all.

Satellite imagery was not detailed enough, so a (slow) drone will be 
used for mapping the area in high resolution. This will take days or 
even weeks. In my experience the colours and quality differs per flight 
(due to the weather and sun angle) making AI learning very hard.

Luckily we have many hands around and can split the task! My job is to 
make this as easy as possible, in QGIS

> 
> If not, can you build a tool that will permit you to select multiple buildings at a time and only enter the information once?

Yes, that was the 2nd step. It could also be some kind of tool that 
works like a highlighter. Just pick the "red" one from a list and start 
clicking all the damaged buildings. That would even mean only 1 click 
per building.

Or, more generic, an edit tool where you can choose the field and the 
value to set, and start clicking. I think I'm developing a new plugin 
idea here!!

> 
> Nicolas Cadieux
> Ça va bien aller!
> 
>>> Le 28 mai 2020 à 02:33, Raymond Nijssen <r.nijssen at terglobo.nl> a écrit :
>> Does anyone know if there is a tool in QGIS to quickly classify features manually?
>>
>> I have a layer with 17,000 buildings, all need to be set to 1 of 5 values. I'm thinking about making a (quick and dirty) plugin that:
>>
>> - On clicking the building shows a popup menu with the 5 choices
>> - Clicking the choice would update the value and change the color (redraw)
>>
>> Every click less really counts here. I already set up a form widget but also having the location of the menu near the building polygon is way more efficient. (I mean, no need to cross the screen with your mouse cursor.)
>>
>> Thanks!
>>
>> Raymond
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