Geo SHP-data from official Belgium site contains sector regions. So I need to combine sectors to obtain city regions. The sectors are defined as Polygons, list of Polygons and FilledCurves. These elements must be combined to form one Polygon per City. So I made a formula (see Notebook: result) to combine all the data (Length=19794) to form a list of cities (Length=581). Everything seems ok during several test on a small dataset using Take[cityX,30] instead of cityX. The resulting Polygons where clean and as expected.

The Notebook crashed when I used the full set (581), no error message. On the desktop version I had a full stop at city 12002 (after evaluate notebook) or 13031 (after start kernel + evaluate notebook). The cloud version comes to a halt af a more erratic number of cities.

I did some inspection of the original data at location 12002 and next one 12005. No abnormalities.

No error messages and full stop. What is going wrong here?

Imported data file: belgData.mx