The skirt that should be worn over this one.
It's a circle skirt as well as the other one. I folded the fabric to get two layers. I calculated the perimeter in the old way: o=2*pi*r, when o is the girth.
So I got the perimeter and I drew one fourth of the circle to the corner. You mustn't forget to add a seam allowance to the free edges of the skirt and as well one centimeter to the circle (upwards).
Then I measured from the little circle the lenghts I had measured on myself. Added seam allowance again. I joined the points with a spline and got the shape.
The waist part was made easily - a tunnel with an elastic.
Then I drew a curve thirty centimeters from the lower edge - I didn't want the skirt to be shorter then this at any point.
I drew a random curve in this area that should mark the hem.
I double-folded the lower edge and sewed.
At the most curved places I helped myself with basting, the rest was only ironed before sewing.
Done.