CHART PLOT 



345 



and the shifting of the cross tapes is continued until the chart- 

 ing of the quadrat is completed. 



Prior to mapping, and before there has been any abnormal 

 disturbance of the vegetation, a photograph should be taken of 

 the plot. For purposes of future comparison it is highly desir- 

 able to establish the exact location of the camera and the direc- 

 tion of the exposure. This is done by placing a stake at the 

 spot where the camera is located and another in line with the 

 angle of the camera. " Position " photographs have proved of 

 much value in comparative studies of plots observed over a 

 period of years. 



The Pantograph for Mapping Chart Plots. — The immense 

 amount of painstaking work involved in charting the vegetation 

 in exact position led Hill ^ to apply the pantograph, an instru- 

 ment formerly considered as adapted only for use on a drafting 



Fir,, i:- THE I' AXTOCRAPH IN USE ON A CHART PLOT. 



The special sample-plot steel Ruide tapes are in position, and the plot is staked at 



diagonally opposite corners. 



table, to the mapping of vegetation on chart plots. The results 

 from the use of the pantograph are highly satisfactory for re- 

 producing the outlines of tufts of vegetation as well as for 



' Hill, Robert R., "Charting Quadrats with a Pantograph." Ecology, Vol. i. 

 No. 4, pp. 270-273, 1920. 



