plot.qrfactor : sp.label: no visible global function definition for
  ‘coordinates’
plot.qrfactor: no visible global function definition for ‘slot’
plot.qrfactor: no visible global function definition for ‘slot<-’
plot.qrfactor: no visible global function definition for ‘text’
plot.qrfactor: no visible global function definition for ‘layout’
plot.qrfactor: no visible global function definition for ‘kmeans’
plot.qrfactor: no visible global function definition for ‘polygon’
plot.qrfactor: no visible global function definition for ‘points’
plot.qrfactor: no visible global function definition for ‘mahalanobis’
plot.qrfactor: no visible global function definition for ‘qqplot’
plot.qrfactor: no visible global function definition for ‘qchisq’
plot.qrfactor: no visible global function definition for ‘ppoints’
plot.qrfactor: no visible global function definition for ‘spplot’
plot.qrfactor: no visible global function definition for ‘bpy.colors’
plot.qrfactor: no visible global function definition for ‘gray.colors’
plot.qrfactor: no visible global function definition for ‘aggregate’
plot.qrfactor: no visible global function definition for ‘aov’
plot.qrfactor: no visible global function definition for ‘kruskal.test’
plot.qrfactor: no visible global function definition for ‘dist’
plot.qrfactor: no visible global function definition for ‘hclust’
plot.qrfactor: no visible global function definition for ‘rect.hclust’
plot.qrfactor: no visible global function definition for ‘na.omit’
plot.qrfactor: no visible global function definition for ‘readOGR’
plot.qrfactor: no visible global function definition for ‘wilcox.test’
plot.qrfactor: no visible global function definition for ‘TukeyHSD’
rq: no visible global function definition for ‘readOGR’
rq: no visible global function definition for ‘slot’
rq: no visible global function definition for ‘read.csv’
rq: no visible global function definition for ‘read.table’
rq: no visible global function definition for ‘slot<-’
rq: no visible global function definition for ‘na.omit’
rq: no visible global function definition for ‘cor’
rq: no visible global function definition for ‘kmeans’
Undefined global functions or variables:
  TukeyHSD aggregate aov bpy.colors coordinates cor dist gray.colors
  hclust kmeans kruskal.test layout mahalanobis na.omit points polygon
  ppoints qchisq qqplot read.csv read.table readOGR rect.hclust slot
  slot<- spplot text wilcox.test
Consider adding
  importFrom("grDevices", "gray.colors")
  importFrom("graphics", "layout", "points", "polygon", "text")
  importFrom("methods", "slot", "slot<-")
  importFrom("stats", "TukeyHSD", "aggregate", "aov", "cor", "dist",
             "hclust", "kmeans", "kruskal.test", "mahalanobis",
             "na.omit", "ppoints", "qchisq", "qqplot", "rect.hclust",
             "wilcox.test")
  importFrom("utils", "read.csv", "read.table")
to your NAMESPACE file (and ensure that your DESCRIPTION Imports field
contains 'methods').