In ArcGIS 10.2 (with spatial analyst ext). I have two point layers.

One represents schools and one represents students. For each school I have a number of students living near the school I need to "grab" with a circle. The circles (a polygon layer) are something I will need later for another process.

I could have sworn ESRI has a tool to do this but I can't find it or remember key words to aid my search.

Example of what I am looking for: School(point) has an attribute of 100. I also have a point layer with thousands of students. I want to create a circle polygon (with school as the center) that contains 100 students.

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    Try searching for the Buffer tool to create your circles but to work out the size to find the nearest 100 points in the other feature class will probably mean using Point Distance first. – PolyGeo Nov 5 '14 at 21:11
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    I would start with a point distance from students to schools which will indicate with the field near_fid which school they're closest to then select for each near_fid, where the result is greater than 100 sort the table by distance, take the 100 closest then export and remove the school and students from the pool iteratively until there are no schools left. This would be best done in python as you'll need to cursor through the table after it's sorted. On the next iteration the leftover students need to go to a school that is not closer but makes up the 100. This sounds like homework. – Michael Stimson Nov 5 '14 at 21:27
  • I think I am missing something. Are you saying then take the distance of the furthest 100th student and create a buffer? Why do i remove schools? And not HW, just work. – Lauren Nov 5 '14 at 21:38
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    You need to remove the school for the next iteration otherwise the students that are already closer to that school will remain closer to a 'full' school and not be allocated to the next closest. Then take the distance to the furthermost student and that's your buffer distance; each school will have a different distance (which is supported using buffer_field instead of buffer_distance in the buffer tool) – Michael Stimson Nov 5 '14 at 21:42
  • Be aware that you will have overlapping buffers and students contained in the overlap area. If you want to truly polygonize it you will need to turn the students into Thiessen (Voronoi) polygons and dissolve by near school ID - this will give planar polygons that will be guaranteed to only include the students allocated to that school. BTW I do help with homework but the answers are longer. – Michael Stimson Nov 5 '14 at 22:19

You should be able to use the Generate Near Table GP tool. Set the maximum number of closest matches parameter to 100 or whatever the value of the attribute in schools is. The number is fixed so if you need it to change per school then loop through your schools based on the attribute value.

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