Valley Forge National Historical Park: Accuracy Assessment Matrix

Table 3.� Contingency matrix and calculated errors for the thematic accuracy assessment of the association-level vegetation map at Valley Forge National Historical Park.

	Mapped Vegetation association
Accuracy Assessment Observation	Class	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	Total	Errors of Commission (Percent Correct)
Silver maple floodplain forest	1	2					5																7	28.6
Northern catalpa planted forest	2		1																				1	100
Cropland	3			12																			12	100
Developed land	4				28					1													29	96.6
Dry Oak Forest	5					33				1								2					36	91.7
Riverine floodplain forest	6						10				2												12	83.3
Grassland (mowed)	7				2			21		1									1				25	84
Grassland (tall grass)	8			8				9	28		1												46	60.9
Tuliptree � Oak Forest	9					6	1			24				1									32	75
Northeastern modified successional forest	10					1	2			2	29												34	85.3
Old nursery site	11									1		5											6	83.3
Old quarry/reclamation site	12												1										1	100
Planted ornamental tree grove	13													2									2	100
Mixed white pine - hardwood plantation	14														1								1	100
White pine plantation	15														2	5							7	71.4
Successional old field/shrubland�	16								1								4						5	80
Chestnut Oak � Black Birch Talus Slope	17					1												2					3	66.7
Transportation corridor	18					1													20				21	95.2
Eastern hemlock planted forest	19																			1			1	100
Water	20						1														21		22	95.5
Wet meadow�	21																					5	5	100
Total		2	1	20	30	42	19	30	29	30	32	5	1	3	3	5	4	4	21	1	21	5	308
Errors of Omission (Percent correct)		100	100	60	93.3	78.6	52.6	70	96.6	80	90.6	100	100	66.7	33.3	100	100	50	95.2	100	100	100
																			Total points Correct				255
																			Overall Accuracy				82.80%
																				Kappa index			81.20%
																90% confidence interval for Kappa index							3.80%