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GRAPHIC PRESENTATION

National Rrsourcrs Board. "State Planning," 193S. SCALE .5

A. Migration Into and fronn North Dakota for the Period from 1920 to 1930.

1. In the original of this map, the migration from North Dakota was indicated in red ink.

2. The two groups of figures in each state give the inflow and outflow. The top figure

represents the outflow to North Dakota, the bottom figure the inflow from North Dakota.

3. While there is no scale to give the exact proportion of the width of the lines to the

number of people, the width of the lines gives some indication ot this.

Amrrican Petroleum Institute. N. Y. C, •Petroleum Factt and Figurei," 193 7. SCALE .8

B. Directional Flow Map of Crude Oil and Gasoline Pipe Lines in the United States in 1936.

There is no quantity representation in this map. It is purely a directional flow.

FLOW MAPS

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GRAPHIC PRESENTATION

National Re«ourc«i Board, "State Planning," 1935. Average Daily Traffic on Michigan Trunk Line Highways Based on the Years 1930 and 1931.

1. The legend for this traffic map might have been better if a scale for the widths of

line had been given.