Hi folks, greetings from Paris ! I am currently working on a spatial statistics project. I intend to develop progressively some gretl functions to compute spatial correlation tests.
A difficulty is to handle spatial neighborhood matrices that are needed to compute those tests. More specifically, I have an external file storing the matrix in vector form: in the first column the list of the spatial units, and in the second the list of their neighbors. The difficulty is that having two different datafiles of different dimensions does not easily allow to pass the contiguity matrix into the datafile containing the data to be analysed. I guess it could be done with a null list and an append command into a loop, provided a recoding is done so that the neighbor matrix is recoded eg, in the following format: Obs No Neighbor1 Neighbor2 Neighbor3 ... Neighbor n 1 nn1 nn2 nn3 nnN 2 nn1 ... n where nn1-nnN is the Observation No of unit n In this case handling is perfect. For now, I use a third party application to do that. But would like to avoid that but I do not succeed in opening the contiguity matrix file, recode it and store inot the datafile. Any advice ? Two, do the matrix commands support the boolean product command ? It would be very useful for contiguity matrix handling purposes (ie, to compute the neighbors of neighbors, etc...). Three, if you are interested in this topic, I will gladly contribute my developments to the community. Cheers ! Franck -- Franck Nadaud Economiste CIRED UMR 8568 CNRS - EHESS 45 bis avenue de la Belle Gabrielle 94736 Nogent-sur-Marne Cedex TEL 33-1-43-94-73-94 FAX: 33-1-43-94-73-70 MOB: 06-07-39-92-75 France
