Rim Specifications:
Brand: Rigida - Ryde
Model: Dutch 19
Color: black
Size (Inch/MM): 28" / 622 
External width (MM): 24
Internal width (MM): 19
External high (MM): 30
Weight (GR): 633
Material: Aluminium
Single-walled / Double-walled: Double-walled
Single eyelets / Double eyelets: No eyelets
Number of spoke holes: 36
Spoke nipple size: 14
Brake surface present: No

Data for spoke length calculations using the Sapim spoke size calculator:
Internal diameter of the rim (MM *Not ERD*): 572
Rim thickness (MM): 2
Number of spokes in the wheel: 36
Number of crossings gear side: of your choice
Number of crossing non-gear side: of your choice

Link to spoke calculator: www.sapim.be/spoke-calculator