Merge pull request #59 from michelbeeren/patch-2

Update ahn.tex

appendices/ahn/ahn.tex

@@ -40,13 +40,13 @@ \chapter{Extra information about the AHN datasets}%
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 It should be noticed that in AHN5 the class 6/\texttt{building} is for the roofs of the buildings \emph{only}, the façades of a building are in class 1/\texttt{unclassified}.
-This is in contract to previous versions in which all points representing a building were classified as 6/\texttt{building}.
+This is in contrast to previous versions in which all points representing a building were classified as 6/\texttt{building}.
 
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 Observe also that in AHN the points representing vegetation are not classified as such, and vegetation is never explicitly classified.
 \marginnote{vegetation is classified as $1$/\texttt{unclassified}}
-The is because the aim of the AHN project is mostly to model dikes and to protect us from floods, and vegetation is not very important for this use-case.
+This is because the aim of the AHN project is mostly to model dikes and to protect us from floods, and vegetation is not very important for this use-case.
 The class $1$ is thus used for vegetation, but other objects such as street furniture (\eg\ lampposts) or cars are also classified as $1$.
 
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