Warren H. Manning (1860 –1938) worked for Frederick Law Olmsted as a horticulturalist before establishing his own landscape architecture practice. By about 1910, electricity had become widespread, and light tables (drawing tables with translucent glass tops illuminated from below) were invented to simplify the tracing of drawings. In 1912, Manning made a study that used map overlays as an analysis method, much as is done today. By using overlays on a light table, he made a landscape plan for the entire country, which was published in Landscape Architecture in June 1923 (Steinitz 2012).