  We present a new data product, called Space-Weather MDI Active Region Patches
(SMARPs), derived from maps of the solar surface magnetic field taken by the
Michelson Doppler Imager (MDI) aboard the Solar and Heliospheric Observatory
(SoHO). Together with the Space-Weather HMI Active Region Patches (SHARPs),
derived from similar maps taken by the Helioseismic and Magnetic Imager (HMI)
aboard the Solar Dynamics Observatory, these data provide a continuous and
seamless set of maps and keywords that describe every active region observed
over the last two solar cycles, from 1996 to the present day. In this paper, we
describe the SMARP data and compare it to the SHARP data.
