GPS and colors

  • As the version has recently updated, I am not sure how the GPS really works. Is it as before that we need to mesure (press botton each time when at a corner) each corner or can we simply press start, walk around the field and when again at the starting point press again and it measures automatically the area?

  • For the sections in the interviewer app: we see that even though we did not even start a section, it appears green as being completed. Can you perhaps explain us why this is the case and could that be changed? This is of course a bit unfortunate for our enumerator teams because they are in this case not able to distinguish between sections already filled out and not completed yet.
    Thank you very much for you’re a possible asap feedback on this to help us out
    Best regards from Ghana

Dear Sarah,

a while ago I had a feature presentation on this topic:

You focus on the technical details now, but move back conceptually: do you really want to measure a field’s area with GPS if your accuracy can be dozens of meters in each dimension? Very roughly, if your actual field dimensions are 100mx100m and your accuracy is ±20m in each dimension, then your area is anything from 6400 (80x80) to 14400 (120x120) m2. That’s a variation comparable already or even more than the magnitude.

Each GPS question takes an immediate recording of the current position only. 1 point. Please make sure that you do adequate piloting, from taking measures to exporting the data and comparing with benchmark figures before you make a decision to use the questionnaire for the actual survey.

(PS: If you know your field is a square, two points should be sufficient, for a rectangular plot 3 points should be sufficient, for a plot of more complexity you will need more way points.)

Best, Sergiy

Hello Sarah,

  1. GPS question is not affected by recent changes. It works as before. Interviewer presses the button, current location of the tablet is determined and recorded.

Area question is based on satellite images (maps) and has little to do with current location. If you have a map of the Antarctica, you can point the corners there without having to go there.

No question delivers the described hypothetical functionality of real-time walking-measuring-calculating.

  1. The section color is green when it doesn’t have any questions to be answered (otherwise it is blue) and there are no errors (otherwise it is red). You are using the knowledge that there inevitably will be some questions, the computer doesn’t know this.

a) What is the difference between a “section filled out” and “section not completed yet” (define in your own words but in Survey Solutions terms)? If the section doesn’t have ANY question is it first or second?
b) what difference does it make to the interviewer? They should proceed to the next blue section.

What I do sometimes is set a condition to the whole section to suppress it until a certain condition holds. This removes the whole mentioning of it until it becomes relevant. If the section contains many groups of questions activated in different situations, this condition may be difficult to write. Or it may also confuse the interviewers (“why am I not seeing section X?”).

Best, Sergiy

Dear Sergiy,
THank you very much for your quick Reply!
Just to know if I understood for GPS: they have to press the buttom at EACH Corner of the field (so a quadradic plot 4 Corners means for times) or simply press the buttom when starting and when finished the walk?
Thanks again
Greetings from Ghana