\begin{table}%t1
\caption{6.7~GHz methanol maser properties.}\label{tab1}
%\centerline
 {\small 
\begin{tabular}{l c c c c c c c c}
\hline \hline
Source & NVSS & Maser $(v_{\min},~v_{\max})$ & $v_{\rm s}$ & KDA & $d$ & $d'$ & Quality & $\sigma$ \\
Name & Source & (\kms) & (\kms) & Resolution & (kpc) & (kpc) & Assignment & mJy beam$^{-1}$ \\
(1) & (2) & (3) & (4) & (5) & (6) & (7) & (8) & (9) \\
\hline
10.32--0.15$^a$ & 180900-200456 & (4, 17) & 11.0 & N & $3.4 \pm 0.3$ & $3.4 \pm 0.3$ & & 8.0 \\
10.47+0.02 & 180835--195219 & (58, 77) & 70.1 & F & $10.6 \pm +0.4$ & $10.8 \pm 0.3$ & A & 5.3 \\
10.62--0.38$^a$ & 181028--195548 & (--10, 7) & 0.4 & N & $3.4 \pm 0.3$ & $3.4 \pm 0.3$ & & 1.5 \\
10.95+0.02 & 180942--192629 & (23, 25) & 18.5 & F & $14.2^{\rm +1.3}_{-1.0}$ & $14.3 \pm 1.2$ & A & 1.3 \\
11.03+0.06 & 180939--192116 & (15, 21) & 12.6 & F & $15.0 \pm 1.3$ & $15.0 \pm 1.3$ & A & 1.3 \\
11.93--0.61 & 181401--185324 & (30, 44) & 39.3 & N & $4.2 \pm 0.8$ & $4.0 \pm 0.7$ & A & 2.2 \\
11.99--0.27 & 181245--184039 & (60, 61) & 58.2 & F & $11.3 \pm 0.6$ & $11.5 \pm 0.6$ & A & 1.4 \\
12.20--0.10A & 181242--182417 & (2, 15) & 27.0 & F & $13.5 \pm 1.0$ & $13.6^{\rm +1.0}_{-0.7}$ & A & 1.3 \\
12.20--0.10B & 181242--182417 & & 53.6 & F & $11.6 \pm 0.6$ & $11.8 \pm 0.6$ & A & 1.3 \\
12.68--0.18 & 181355--180124 & (50, 62) & 57.4 & N & $5.1 \pm 0.6$ & $4.9 \pm 0.6$ & A & 5.5 \\
12.79--0.19 & 181414--175543 & (31, 41) & 35.8 & N & $3.8^{\rm +0.6}_{-0.9}$ & $3.6 \pm 0.7$ & A & 2.5 \\
12.90--0.26 & 181444--175223 & (35, 47) & 28.6 & F & $13.4 \pm 1.0$ & $13.6 \pm 0.9$ & A & 2.5 \\
13.18+0.06 & 181405--172832 & (48, 49) & 54.1 & N & $4.8 \pm 0.6$ & $4.6 \pm 0.5$ & A & 2.5 \\
14.09+0.10 & 181545--163858 & (4, 17) & 16.3 & F & $14.7 \pm 1.1$ & $14.8 \pm 0.9$ & A & 1.5 \\
18.06+0.08A$^b$ & 182335--130920 &  & 16.4 & F? & $14.7 \pm 0.9$ & $14.8 \pm 0.8$ & A & 2.0 \\
18.06+0.08B$^b$ & 182335--130920 & (45, 57) & 60.1 & F? & $11.7 \pm 0.5$ & $11.9 \pm 0.4$ & A & 2.0 \\
18.46--0.00 & 182436--125106 & (47, 50) & 56.5 & F & $11.9 \pm 0.5$ & $12.1 \pm 0.4$ & A & 2.2 \\
19.48+0.15 & 182604--115234 & (20, 27) & 19.8 & F & $14.4 \pm 0.8$ & $14.5 \pm 0.7$ & A & 2.2 \\
19.61--0.13 & 182716--115322 & (52, 54) & 58.6 & F & $11.8 \pm 0.5$ & $12.0 \pm 0.4$ & A & 1.7 \\
23.43--0.18 & 183438--083043 & (94, 113) & 104.5 & F & 9.2 & $9.6 \pm 0.3$ & B & 3.3 \\
24.50--0.03 & 183606--073106 & (108, 116) & 109.2 & F & 8.6 & $9.3^{\rm +0.3}_{-0.5}$ & A & 1.5 \\
24.67--0.14 & 183652--072453 & (111, 114) & 111.4 & N & 7.2 & $6.4 \pm 0.5$ & B & 2.4 \\
24.78+0.08 & 183610--071124 & (106, 115) & 108.6 & N & 6.8 & $6.1 \pm 0.4$ & B & 1.6 \\
25.70+0.04A & 183804--062523 &  & 53.3 & F & $11.8 \pm 0.6$ & $12.0 \pm 0.4$ & A & 1.0 \\
25.70+0.04B & ? & (89, 101) & 102.0 & ? & $\ldots$ & $\ldots$ &  & 1.0 \\
27.28+0.15 & 183610--071124 & (34, 37) & 36.3 & F & $12.7 \pm 0.7$ & $12.9 \pm 0.5$ & A & 0.8 \\
28.30--0.38A$^c$ & 184415--041757 &  & 44.8 & F & $12.1 \pm 0.6$ & $12.3 \pm 0.5$ & A & 0.8 \\
28.30--0.38B$^c$ & 184422--041746 & (79, 93) & 75.6 & F & $10.3 \pm 0.6$ & $10.6 \pm 0.3$ & A & 0.8 \\
30.70--0.07 & 184735--020143 & (85, 90) & 101.0 & F & 8.5 & $9.0 \pm 0.4$ & A & 4.4 \\
30.76--0.05 & 184738--015731 & (88, 95) & 91.6 & F & 8.5 & $9.0 \pm 0.4$ & B & 4.4 \\
30.82--0.05 & 184746--015451 & (91, 110) & 105.7 & F & 8.5 & $9.0 \pm 0.4$ & B & 4.4 \\
32.97+0.04 & 185124+000412 & (89, 93) & 93.2 & F & 8.3 & $8.7 \pm 0.4$ & B & 2.0 \\
33.13--0.09 & 185207+000819 & (71, 81) & 93.8 & F & 8.2 & $8.7 \pm 0.4$ & B & 1.3 \\
33.40+0.01A & 185220+002552 &  & 72.3 & F & $9.8 \pm 0.7$ & $10.0 \pm 0.4$ & A & 1.3 \\
33.40+0.01B & 185216+002531? & (96, 107) & 105.4 & T & 7.1 & 7.1 & A & 1.3 \\
41.10--0.22 & 190711+070956 & (63, 64) & 59.4 & F & $9.1 \pm 0.8$ & $9.4 \pm 0.4$ & A & 1.9 \\
43.87-0.77 & 191426+092236 & (47, 53) & 55.0 & F & $8.8 \pm 0.8$ & $9.1 \pm 0.5$ & A & 2.7 \\
45.07+0.13 & 191320+105054 & (57, 60) & 63.0 & F & 7.7 & $8.0 \pm 0.5$ & B & 1.4 \\
48.90-0.27$^d$ & 192214+140319 & (63, 73) & 66.5 & ? & $7.0 \pm 1.5$ & $7.0 \pm 1.5$ &  & 1.4 \\
50.29+0.69 & 192127+154406 & (26, 33) & 25.9 & F & $9.3 \pm 0.7$ & $9.3 \pm 0.3$ & A & 1.3 \\
81.87+0.78$^e$ & 203837+423759 & (0, 13) & 1.7 & F & 2.0 & 1.2 & B & 2.9 \\
\hline
\end{tabular}}
\medskip
Column (1) contains the source names. Sources which have two recombination line velocities in the same line of sight are suffixed~A and B for distinction. Column (2) lists the NVSS source that is associated with the methanol maser. Column (3) shows the velocity extent of the maser emission, and Col.~(4) shows the systemic velocity, $v_{\rm s}$ derived from the radio recombination line. Column~(5) lists the KDA resolution specifying whether the source is at the near distance (N), far distance~(F), tangent point~(T), or whether the KDA is unresolved (?). Column~(6) shows the distance~$d$, calculated from the conventional method using the C85 rotation curve, while Col.~(7) shows $d'$, which is the modified kinematic distance calculated using the methodology described in Sect.~4. Column~(8) indicates the quality of the KDA resolution (A or B), and Col.~(9) lists the rms noise in the 21~cm continuum image. Errors for $d$ are not listed when $v_{\rm s}+10$ exceeds the tangent point velocity, $v_t$, since such velocities are forbidden, and cannot be converted to a meaningful distance.\\
$^a$ Distance from \citet{blum01}; $^b$ {Source has ambiguity between two recombination lines}; $^c$  {The continuum source associated with the A and B sources may be reversed}; $^d$  {Distance from \citet{genz81}}; $^e$ {$d'$ for this source is the distance to the tangent point}.
\end{table}