Export polygon from Aggregate

Dear all,

I have defined a polygon field in ODK collect with 15,999 characters. It seems to work well regarding the collection of polygon data. But the challenge now is to retrieve it from Aggregate. I tried export to CSV, KML and JSON and tried to load it into QGIS. I tried downloading with Briefcase and see how to convert it to a GIS format. I also tried Mobile Data Conversion Kit from GeoODK, but this also seems to bug... (never ending processing...) I also set up a connection with Google Fusion, but this does not seem to read the geoformat of Aggregate. Is there any solution how to do this and show my polygon features?

PS: My polygon field is in a group & has 15,999 characters. Maybe this is the bottleneck. Any suggestions of people who experienced the same problem? Thanks!

geometry storage into aggregate is not "standard". The string stores 4 dimension for each edge and ends with the first one (to close the line). We faced it and then created a function on PostgreSQL to generate proper geometries. So this post might help you if you store your datas into PostgreSQL :

And, in any case, this discussion will be interesting to follow : Add a GeoJSON export to Briefcase and Aggregate


Thanks Mathieu,

I will see if I can manage this. As I understand there is no simple straight forward solution yet. But why is the Mobile Data Conversion Kit from GeoODK not working...? I tried several things, but it seems that this tool has a serious bug.

"Mobile Data Conversion" has not been updated since 2014, and as far as I can see into the Github source files, this application does only manage lat/long based point geometries.
I don't know which software you usually use to manage GIS data.
Did you get a look at the QgisODK extension for QGIS : https://github.com/enricofer/QgisODK

Hi Mathieu,

Thanks for the clarification about Mobile Data Converter. I use QGIS. I tried the QgisODK tool but it appears that you need to generate your ODK collect form through this tool in order to download the polygons...(?) I think. Anyway, it gives me an error as soon as I try to connect to my aggregate...

I am wondering how all other users using the geotracing tool are now downloading or visualising their polygon data... As the geotrace/geoshape tool is quiet important for many users, I think it is quiet urgent to have something userfriendly to download the polygon data in user friendly format...

Eddy, I think @ggalmazor eared you :wink:

Don't hesitate to contact @Enrico_Ferreguti about QgisODK


I agrre with you, the more it will be easy to get GIS data from aggregate for non DBA users, the more ODK will be use to collect geographical data.

I seems so...:slight_smile: Interesting! Ik will try it immedeately...! Many thanks!

Works smootly! Great work.


Hi, folks! We've just released Briefcase v1.13, which includes a new GeoJSON export option. Check it out: ODK Briefcase v1.13

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