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| From | rraciborski@stata.com |
| To | statalist@hsphsun2.harvard.edu |
| Subject | st: spmat error in stata |
| Date | Tue, 08 Nov 2011 16:12:02 -0600 |
Ajita Atreya <ajita63@hotmail.com> tried to create a banded spatial-weighting matrix using the user-written -spmat- but -spmat- refused: > I am trying to create spatial matrix for more than 24000 observation on > properties sold. I used spmat idistance ccounty point_y_1 point_x_1, id( _ID) > banded vtruncate(1/500) but got an error message "object not created - bands > must be <= 6078". What should I do to create band <=6078. Before calling -spmat-, Ajita may try using the sorting method described in section 5 of the spmat working paper available at http://econweb.umd.edu/~prucha/Papers/WP_spmat_2011.pdf. The idea behind the sorting method is to pick a spatial unit that is remote relative to the other spatial units, calculate the distance from that unit to all the other units, and sort the data according to the distance variable. The spatial-weighting matrix constructed from the sorted dataset is very likely to have a usable band as the sorting pushes the nearby spatial units toward the diagonal of the matrix. --Rafal rraciborski@stata.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/