topic Weighted Population? in ArcGIS Spatial Analyst Questions https://community.esri.com/t5/arcgis-spatial-analyst-questions/weighted-population/m-p/399391#M5618 <HTML><HEAD></HEAD><BODY><SPAN>I have a set of 15,000 grid points and a raster of Census population.&nbsp; For each point, I need to calculate a buffer radius that sums to a certain population value (say 50,000 for example) by incrementally expanding a buffer at each point to achieve that threshold.&nbsp; Does anyone know how I can accomplish this type of analysis?</SPAN><BR /><BR /><SPAN>Alternately, I have been trying to do this in using the "Near Table" tool in the "Proximity ArcToolBox".&nbsp; In this case, I have 15,000 grid points and approximately 110,000 census block centroids with population attached.&nbsp;&nbsp; I am successful in that I can create a buffer that "overshoots" the block points required to sum to 50,000 person.&nbsp; My next step is to I export the table into Excel and reduce the table by sorting on the grid point ID and then sorting on the Distance table.&nbsp; At that point, I can let the population accumulate and then I get rid of all records that exceed 50,000.&nbsp; This has been a workable solution as a prototype (ie subset of census blocks).&nbsp; However, I need a more automated solution for two reasons.&nbsp; 1)&nbsp; I can't reduce the table as described above in Excel without chopping an extremely large dataset into several smaller tables.&nbsp; And 2) My table is extremely large (I estimate it would be around 50,000,000 records) and I don't have the processing power to calculate a table of that size.</SPAN><BR /><BR /><SPAN>Any ideas for how I can accomplish this task?&nbsp; Either the raster solution or the census block centroid solution would work.&nbsp; All I need at the end of the process is a table with distance of a radius and a population sum for each grid point.</SPAN></BODY></HTML> Thu, 01 Dec 2011 13:30:34 GMT KevinMatthews 2011-12-01T13:30:34Z Weighted Population? https://community.esri.com/t5/arcgis-spatial-analyst-questions/weighted-population/m-p/399391#M5618 <HTML><HEAD></HEAD><BODY><SPAN>I have a set of 15,000 grid points and a raster of Census population.&nbsp; For each point, I need to calculate a buffer radius that sums to a certain population value (say 50,000 for example) by incrementally expanding a buffer at each point to achieve that threshold.&nbsp; Does anyone know how I can accomplish this type of analysis?</SPAN><BR /><BR /><SPAN>Alternately, I have been trying to do this in using the "Near Table" tool in the "Proximity ArcToolBox".&nbsp; In this case, I have 15,000 grid points and approximately 110,000 census block centroids with population attached.&nbsp;&nbsp; I am successful in that I can create a buffer that "overshoots" the block points required to sum to 50,000 person.&nbsp; My next step is to I export the table into Excel and reduce the table by sorting on the grid point ID and then sorting on the Distance table.&nbsp; At that point, I can let the population accumulate and then I get rid of all records that exceed 50,000.&nbsp; This has been a workable solution as a prototype (ie subset of census blocks).&nbsp; However, I need a more automated solution for two reasons.&nbsp; 1)&nbsp; I can't reduce the table as described above in Excel without chopping an extremely large dataset into several smaller tables.&nbsp; And 2) My table is extremely large (I estimate it would be around 50,000,000 records) and I don't have the processing power to calculate a table of that size.</SPAN><BR /><BR /><SPAN>Any ideas for how I can accomplish this task?&nbsp; Either the raster solution or the census block centroid solution would work.&nbsp; All I need at the end of the process is a table with distance of a radius and a population sum for each grid point.</SPAN></BODY></HTML> Thu, 01 Dec 2011 13:30:34 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/weighted-population/m-p/399391#M5618 KevinMatthews 2011-12-01T13:30:34Z Re: Weighted Population? https://community.esri.com/t5/arcgis-spatial-analyst-questions/weighted-population/m-p/399392#M5619 <HTML><HEAD></HEAD><BODY><SPAN>Seems to me a raster solution is a lot more doable.</SPAN><BR /><BR /><SPAN>My suggested approach is to make a set of rasters built using the focal statistics function (sum) using increasing buffer sizes. Code the buffer distance in the grid name (this could simply be a sequence number "%n%" in ModelBuilder if you are using iteration). </SPAN><BR /><BR /><SPAN>When you're done with this, run Extract Multi-Values To Points using your grid cell centroid points against all your focalsum rasters. The resulting point table will have 15,000 rows and can I think you can easily process the table in Excel from there.</SPAN></BODY></HTML> Fri, 02 Dec 2011 17:15:50 GMT https://community.esri.com/t5/arcgis-spatial-analyst-questions/weighted-population/m-p/399392#M5619 curtvprice 2011-12-02T17:15:50Z