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From |
Yuval Arbel <yuval.arbel@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: calculating many distances and storing them in many new variables |

Date |
Fri, 21 Oct 2011 10:40:06 +0200 |

Anna, I'm not sure what your precise goal is. But if your target is only to map what hospital each patient went, may I suggest the following: Suppose you have a column of coordinates under "patient" and another column under "hospitals" If you are working with STATA11 you can try running: reg patient i.hospitals Let me show you what is the output you get by using one of the examples I ran: I collected a small dataset, which measures land values (rent) and distance from Tel Aviv center (distance): . reg rent i.distance Source | SS df MS Number of obs = 55 -------------+------------------------------ F( 9, 45) = 12.43 Model | 294279904 9 32697767.1 Prob > F = 0.0000 Residual | 118368183 45 2630404.07 R-squared = 0.7131 -------------+------------------------------ Adj R-squared = 0.6558 Total | 412648087 54 7641631.24 Root MSE = 1621.9 ------------------------------------------------------------------------------ rent | Coef. Std. Err. t P>|t| [95% Conf. Interval] -------------+---------------------------------------------------------------- distance | 1000 | -8245.833 1238.71 -6.66 0.000 -10740.72 -5750.943 1500 | -8087.026 1038.817 -7.78 0.000 -10179.31 -5994.741 2000 | -6353.833 1067.634 -5.95 0.000 -8504.158 -4203.509 2500 | -7560.333 1480.542 -5.11 0.000 -10542.3 -4578.37 3000 | -6545.958 1097.999 -5.96 0.000 -8757.442 -4334.475 3500 | -9500 1324.237 -7.17 0.000 -12167.15 -6832.85 4000 | -9891.905 1119.184 -8.84 0.000 -12146.06 -7637.752 4500 | -10258.33 1238.71 -8.28 0.000 -12753.22 -7763.443 5000 | -11600.33 1872.753 -6.19 0.000 -15372.25 -7828.414 | _cons | 13433.33 936.3767 14.35 0.000 11547.37 15319.29 ------------------------------------------------------------------------------ Note that the distance variable includes values from 500 to 5000 meters. The command made the 500 meter distance the base category. On Fri, Oct 21, 2011 at 5:13 AM, Maria Ana Vitorino <vitorino@wharton.upenn.edu> wrote: > Dear StataList users, > > Suppose we have the following toy data which has a list with patients, the > hospital to which they went (hosp_ch) and the coordinates for both. > > patient_id hosp_ch lat_pat lng_pat lat_hosp lng_hosp > 1 a 2 4 5 > 6 > 2 a 1 3 5 > 6 > 8 c 3 5 10 > 12 > 9 a 5 2 5 > 6 > 12 b 8 6 8 > 9 > > > What I would like to do is: > **To create new variables with the distances from every patient to every > possible hospital in the data. So, I would like 3 new columns which will > contain the distance from each patient to each hospital in the data. > **Also, I would like to have those new columns labeled dist_a, dist_b and > dist_c. > > Is there an efficient way to achieve this? > In the real data, I have many more patients and hospitals (hundreds in fact) > so I would like to generate these variables in an as automated way as > possible. > > Any help is appreciated. > Thanks! > Ana > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > -- Dr. Yuval Arbel School of Business Carmel Academic Center 4 Shaar Palmer Street, Haifa, Israel e-mail: yuval.arbel@gmail.com * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: calculating many distances and storing them in many new variables***From:*"Vitorino, Maria Ana" <vitorino@wharton.upenn.edu>

**References**:**st: calculating many distances and storing them in many new variables***From:*Maria Ana Vitorino <vitorino@wharton.upenn.edu>

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