Flow map
Also called: Flow chart, Dynamic map · Topic: Graphical Representation of Data and Thematic Maps · NCERT: Class 12, Ch 3 "Graphical Representation of Data"; Class 12, Ch 4 "Spatial Information Technology"
Meaning
A flow map is part graph and part map. It shows how goods, people or vehicles move between a starting point (origin) and an end point (destination). Each route is drawn as a band, and the band's width matches the volume moved, so a thicker band means more traffic. NCERT calls it a "dynamic map" because it shows movement, not things that stay in one place. It can use two kinds of data: the number and frequency of vehicles in each direction, or the number of passengers or amount of goods carried.
Example
NCERT's flow map of trains in Delhi uses a scale of 1 cm = 50 trains. The Old Delhi–New Delhi route has 50 trains and gets a 10 mm band. The Udyog Nagar–Tikri Kalan route has only 6 trains and gets a 1.2 mm band. A terraced scale (a stepped key of band widths) acts as the legend.
Don't confuse with
- A desire-line map joins each origin and destination with a straight line. A flow map follows the actual routes.