How can draw building sketch and calculate area by using ODK

Mark_Kiwango · August 20, 2018, 12:03pm

Hi, I was collect data based on building characteristics but I can't draw a sketch of the buildings, also measurement and area calculation

janna · August 20, 2018, 2:51pm

Hi @Mark_Kiwango,
What exactly are you trying to do with your data collection. There are a few possibilities:
-You can collect an image type in ODK that allows you to sketch a rough drawing
-you can enter or collect GPS points of the footprint of a building and calculate the area the building covers
-you could enter room or building measurements in a data collection form and use the "calculate" question type to calculate area, length, volume, etc.

It all depends on the precise type of data you want to collect. Can you share a bit more info so we can help a bit more?
Janna

Mark_Kiwango · August 20, 2018, 7:32pm

I want to draw this attachment photo in odk with area calculation

Mark_Kiwango · August 20, 2018, 7:34pm

Please help me with vivid example

janna · August 20, 2018, 8:20pm

Hmmm, now that's something I don't think ODK will do for you. Unless someone else can enlighten me.

yanokwa · August 20, 2018, 9:37pm

@janna is correct that this isn't really possible in ODK unless you write a lot of custom code.

Xiphware · August 20, 2018, 11:42pm

FYI you certainly wont get the resolution you require for a precise area measurement of a room, but so that you are aware, the geoshape widget can calculate (larger) areas, of say a paddock. But you will have to actually walk the perimeter to capture all the 'corners'...

As already stated, drawing the layout of a room, assigning precise wall measurements, and calculating areas is probably bit out-of-scope for ODK per se. But I'm sure there are other apps out there for this.

Mark_Kiwango · August 21, 2018, 4:34am

Thanks a lot for reply

Xiphware · August 21, 2018, 5:12am

YW. BTW what you are asking is actually quite tricky when you get into the gritty details. Basically, to calculate the area of a polygon from a bunch of sides, you need not only the length of each side - which you specify - but also the precise angle between them; you assume 90deg everywhere, but that may not be the case in practice. And if you were to try handle non-90deg angles by instead, say, plotting the corners on a grid, you then you may have a granularity issue of your grid not being accurate to 10cm (which your measurements imply)...

Which is all to say, to accomplish what you want to do properly, and accurately, you probably need to investigate dedicated tools/apps designed for this exact purpose.