# Employment Accesibility Index circa 2010. Valley of Mexico Metro Area

## Description

Employment Accesibility Index. The index assumes an squared inverse distance as a criteria for determining the amount of jobs accesible from a Census Tract to all, this way nearer tracts have a mayor contribution for the index than tracts far away. In the table there are three variables: clavegeo = Identificator ee_pot = Accesibility index of total employment with crow flight distance em_pot = Accesibility index of total employment with manhattan distance

## Files

## Steps to reproduce

The following Latex code renders the index formula: E=\sum_{i=1} ^{n} \frac{P_i}{r^2_i} Where E is the accesibility index P is the employment in the i-th census tract r^2 is the squared distance between tracts Data inputs: a) Employment estimations from the DENUE (INEGI Directorio Nacional de Unidades EconÃ³micas 2011) by census tracts. b) Census Tracts shapefile (AGEB urbanas form INEGI) The steps are as follows: 1) Get the centroids for all Census Tracts 2) Get a distance table from all AGEBs (or with a threshold), at least the table must have three fields: La tabla de vecinos debe tener al menos tres campos: ID_origin ID_near Distance. Crow flight distance, Manhattan distance or road network distance 3) Join the employment table to the distance table 4) If ID_Origin = ID_Near: Calculate the weight of employment by the squared inverse distance: jobs/distance^2 5) if ID_Origin ~= ID_Near: Calculate the weight as the employment in the census tract, or get a distance estimate based on the maximum lenght, minimun lenght or the diifference of both to weight the jobs within each tract. 6) Summarize or aggregate the sum of the field with the weights.