How to obtain statistics within a Buffer/Catchment in MapInfo?

Question

I need to calculate the population statistics within a 10 minute drivetime catchment from a point and within 1 Km Buffer from a point in MapInfo, how can I do that can someone please elaborate? I have a population thematic map and I have made a buffer on one location and I need to find the total population living within that area? I am also using a Drivetime addon with MapInfo for drive time catchments and Mapinfo to make Buffers. Many thanks

Answer 1

You should use the Table > Update Column command to calculate the population. Depending on how your population data is stored (point or polygon), how the dialog is filled out will differ:

In the examples:

CatchPopn is the attribute in the drivetime catchments table DTCatch that will receive the calculated population count

PopnCol is the population count attribute in the population source table Population

Points

• Table to update: DTCatch
• Column to update: CatchPopn
• Get value from table: Population
• Join: where object from table DTCatch contains object from table Population
• Calculate: Sum
• Of: PopnCol

Polygons

• Table to update: DTCatch
• Column to update: CatchPopn
• Get value from table: Population
• Join: where object from table DTCatch intersects object from table Population
• Calculate: ProportionalSum
• Of: PopnCol

You might also want to look up dasymetric aereal interpolation techniques.