I want to do a survey using ODKCollect or similar, whereby for each form, my interviewer is directed to a predefined unique point, to collect detailed data about it. The idea is to collect information about a (predefined) random sample of households, in order to infer the characteristics of the whole population.

My guess is that this implies using a database to pre-populate a coordinate field in the survey forms. It seems like this would be a common enough thing to do, but searching turns up nothing - maybe because I don't know the right terminology to describe what I want to do.

Requesting a list of any smartphone-based data collection applications that are capable of doing data collection using a predefined list of coordinates. To be explicitly clear: I am not asking for any opinions on which is the best.

  • If it's predefined, how is it random? – Midavalo Jul 25 '19 at 17:00
  • This is only tangentially related, but you might want to look up the "travelling salesman problem" on this site. It's about finding the best route for a "salesman" (or in your case a surveyor) to take to efficiently visit all the points they need to visit. – csk Jul 25 '19 at 17:00
  • @Midavalo presumably a random subset of points is chosen all at once, rather than randomly choosing the next point for the surveyor to visit. – csk Jul 25 '19 at 17:01
  • @midavalo csk is correct, the random sample is predefined. question edited to clarify – ralph346526 Jul 25 '19 at 17:32
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    List compilation isn't really a strength of the GIS SE "Focused question/Best answer" model. There are a few such questions in the database, from earlier times, but they are generally locked to prevent any more answers. This would be an appropriate topic in the (underutilized) Geographic Information Systems Chat, but there a minimum reputation requirement. – Vince Jul 26 '19 at 16:49

Pretty much any GIS software can create the basic data you need. Here's an example workflow in QGIS:

  1. Use the tool Random points in Extent to make the survey points. This tool allows you to specify how many sampling points to create. You can optionally specify a minimum distance between points, if you want to avoid creating duplicate points or sampling from two households that are right next to each other. (Notice that I said IF. It's up to you to determine if such a distance threshold is a good idea, or if it will add unacceptable bias into your sampling method.)

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    • Or use random points along line with a street layer to make sure your random points are on streets; this might make it easier to get street addresses.
    • Or use random points in polygon with a city/county/state boundary polygon to limit your points to a non-rectangularly shaped area.
  2. Add whatever additional information you need to the point data.

    • Use the Join attributes by location tool to copy information from an existing vector layer to the survey points you created in step one. This assumes you have some data about where there are "households." If you don't already have an existing layer with the data you need, you'll need to acquire it. A tax parcel layer might make a reasonable proxy, but it will include businesses and other non-residence locations. You can get tax parcels from a county auditor for many places in the US. Open Data SE is a good resource for help finding other free geospatial data.
    • Or use a reverse-geocoding service to convert the point locations into street addresses. Again, this method will include some non-residences.
  3. Export into the appropriate format to feed into the app. (Obviously this step depends on the data format required by your survey app.) Add any necessary additional fields to the attribute table. You can do this in the attribute table in QGIS before exporting, or if you export to CSV or XLS format you can do this in Excel.

  4. Import into your chosen data-collection app. Proceed from there.

  • Thanks, but my question was more related to which app to use for steps 3 and 4 – ralph346526 Jul 26 '19 at 15:27
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    I did my best to address the aspects of your question that are within the scope of this website and my knowledge. I know there are apps that allow data collection related to a geospatial point location, but I don't know enough about them to do a pros-and-cons comparison. The software recommendation part of your question will probably get better advice if you ask it on Software Recommendations SE. The Open Data SE community might also have some suggestions. – csk Jul 26 '19 at 15:36
  • here's one app suggestion: Epicollect5 – csk Jul 26 '19 at 15:44

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