Spurious space using \path (wihout draw options)

Question

I'm trying to extract coordinates from a named coordinate, then to use it for an additional drawings in the next code

\documentclass[tikz, border=0.5]{standalone}

\usepackage{tikz}
\usepackage{amsmath}
\usepackage{fmtcount}% http://ctan.org/pkg/fmtcount
\usetikzlibrary{calc, patterns, intersections}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% note, 
%   0 - is an empty space; left uncolored
%   1 - is an other agent; filled with black
%   2 - is an edge; cross-hatched
%   3 - is an unspecified (obscured location); filled with gray
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% model parameters
\pgfmathtruncatemacro{\memory}{2}
\pgfmathtruncatemacro{\visibility}{2}
\pgfmathsetmacro{\maxtablelength}{8}

\begin{document}

    \newcommand*{\ExtractCoordinate}[1]{\path (#1); \pgfgetlastxy{\XCoord}{\YCoord}}%

    % calculate the sizes of the neighborhood
    \newcommand{\GetNeighborhoodSizes}[1]{%
        \xdef\toleft{0}
        \xdef\toright{0}
        \xdef\toup{0}
        \xdef\todown{0}

        \pgfmathtruncatemacro{\tableSize}{2 * \visibility + 1}
        \foreach \columnoffset/\rowoffset[count=\i] in #1 {%
            \ifnum\columnoffset<\toleft%
                \xdef\toleft{\columnoffset}%
            \fi%
            \ifnum\columnoffset>\toright%
                \xdef\toright{\columnoffset}%
            \fi%
            \ifnum\rowoffset<\todown%
                \xdef\todown{\rowoffset}%
            \fi%
            \ifnum\rowoffset>\toup%
                \xdef\toup{\rowoffset}%
            \fi%
            \coordinate (anchor_\i) at (\columnoffset, \rowoffset);
        }

        \xdef\xbase{\toleft}
        \xdef\ybase{\todown}
        \pgfmathtruncatemacro{\pxsize}{\toright - \toleft + 1}
        \xdef\xsize{\pxsize}
        \pgfmathtruncatemacro{\pysize}{\toup - \todown + 1}
        \xdef\ysize{\pysize}

    }

    % draw this neighborhood
    \newcommand{\DrawNeighborhood}[1]{%
        \begin{scope}[shift={(-\xbase, -\ybase)}]
            \draw[fill=black] (0.5, + 0.5) circle (3pt);
            \draw (0, 0) rectangle +(1,1);


            \foreach \value[count=\i] in #1 {%
                \ExtractCoordinate{anchor_\i}
                \begin{scope}[shift={(\XCoord, \YCoord)}]
                    \ifnum\value=0%
                        \draw (0, 0) rectangle +(1, 1);
                    \fi%
                    \ifnum\value=1%
                        \draw[fill=black!80] (0, 0) rectangle +(1, 1);
                    \fi%
                    \ifnum\value=2%
                        \draw[pattern=north west lines] (0, 0) rectangle +(1, 1);
                    \fi%
                    \ifnum\value=3%
                        \draw[fill=black!10] (0, 0) rectangle +(1, 1);
                        \node at (0.5, 0.5) {\bf ?};
                    \fi%
                \end{scope}
            }
        \end{scope}
    }

    % set column and table num
    \newcommand{\DrawAtIndex}[1]{%
        \pgfmathtruncatemacro{\currentstate}{#1}
        \pgfmathtruncatemacro{\tablenum}{ceil((\currentstate + 1) / \maxtablelength)}
        \pgfmathtruncatemacro{\columnnum}{mod(\currentstate, \maxtablelength)}

        \pgfmathsetmacro{\startoffset}{(1 - \xsize * \scalefactor) / 2}
        \begin{scope}[shift={($(left_upper_corner_\tablenum) + (\columnnum + \startoffset, 0)$)}, scale=\scalefactor]
            \DrawNeighborhood{\neighbors}
        \end{scope}
    }

    % drawing parameters
    \pgfmathsetmacro{\scalefactor}{0.4}

    \begin{tikzpicture}
        % common code
        \pgfmathtruncatemacro{\tableheight}{2^(\memory)}
        \pgfmathtruncatemacro{\numberofstates}{2}
        \pgfmathtruncatemacro{\numberoftables}{ceil(\numberofstates / \maxtablelength)}

        \draw (0, 0) grid (2, 4);

        \coordinate (left_upper_corner_1) at (0, 4);

        \newcommand{\neighborsCoordinates}{0/-1}
        \newcommand{\neighbors}{}
        \GetNeighborhoodSizes{\neighborsCoordinates}
        \renewcommand{\neighbors}{0}
        \DrawAtIndex{0}

    \end{tikzpicture}
\end{document}

Basically, everything works fine, except that ExtractCoordinate macro adds this white space under the table.

I have tracked the problem to the \newcommand{\neighborsCoordinates}{0/-1} and then tried to exchange path to coordinate. It solves the white space problem, but breaks the correctness of the image produced (which I also do not understand why).

In the above command, using \newcommand{\neighborsCoordinates}{0/1} produces the right image (for 0/1 pair) and no white space.

How can I fix the issue?