MapInfo Pro

Hello,

I am a new MapInfo Pro user and am attempting to aggregate data in a point file that fall within a polygon file. The points could fall within more than one polygon, in which case the data should be included in each polygon.

I tried the SQL select approach but it is appending the ID from the polygon file to each point that falls within.  Thank you for any guidance.

Hey David

I may need a bit more detail about your data to understand what you are trying to achieve.

You have a point table. Let's call it Points. It has some columns. Let's assume PointID and Sale_Amt.

You have a polygon table. Let's call it Polygons. It has some columns. Let's assume PolygonID.

You can create a SQL Join, where you join these data records:

Select Polygons.PolygonID, Points.PointID, Points.Sale_AmtWhere Polygons.OBJ Contains Points.OBJOrder By Polygons.PolygonID, Points.PointID

This will create a query with 3 columns: PolygonID, PointID, and Sale_Amt.

If a polygon has no points inside its boundary, the polygon will not appear in the result.

If a polygon has one point inside its boundary, the polygon will appear once in the result, also listing the point and the sales amount.

If a polygon has several points inside its boundary, the polygon will appear several times in the result. Once per point. It will also list the point and the sales amount.

Is this what you are looking for?

Cheers

Hello,

I am a new MapInfo Pro user and am attempting to aggregate data in a point file that fall within a polygon file. The points could fall within more than one polygon, in which case the data should be included in each polygon.

I tried the SQL select approach but it is appending the ID from the polygon file to each point that falls within.  Thank you for any guidance.

Thank you for the quick response, Peter!

Yes the above gets me partially to what I need.  I would then like to simply get a sum of the point data, so in your example above I would want a table with polygonID and then Sum(Sale_Amt), where Sum(Sale_Amt) is the total sales within each polygon.

Could this be done using "Update Column"?

Hey David

I may need a bit more detail about your data to understand what you are trying to achieve.

You have a point table. Let's call it Points. It has some columns. Let's assume PointID and Sale_Amt.

You have a polygon table. Let's call it Polygons. It has some columns. Let's assume PolygonID.

You can create a SQL Join, where you join these data records:

Select Polygons.PolygonID, Points.PointID, Points.Sale_AmtWhere Polygons.OBJ Contains Points.OBJOrder By Polygons.PolygonID, Points.PointID

This will create a query with 3 columns: PolygonID, PointID, and Sale_Amt.

If a polygon has no points inside its boundary, the polygon will not appear in the result.

If a polygon has one point inside its boundary, the polygon will appear once in the result, also listing the point and the sales amount.

If a polygon has several points inside its boundary, the polygon will appear several times in the result. Once per point. It will also list the point and the sales amount.

Is this what you are looking for?

Cheers

Hello,

I am a new MapInfo Pro user and am attempting to aggregate data in a point file that fall within a polygon file. The points could fall within more than one polygon, in which case the data should be included in each polygon.

I tried the SQL select approach but it is appending the ID from the polygon file to each point that falls within.  Thank you for any guidance.

Hey

Yes, Update Column would be my tool of choice.

You can use it to join one table with another to calculate points inside a polygon or to summarize values from a column.

In the example below, I'm using Update Column dialog to update the column Incidents in my Voronoi polygon table with the summarized values from the column IncdNo from my Incidents Points table.

Also note that I ensure the Join condition is set to where incidents are within the Voronoi polygons.

Thank you for the quick response, Peter!

Yes the above gets me partially to what I need.  I would then like to simply get a sum of the point data, so in your example above I would want a table with polygonID and then Sum(Sale_Amt), where Sum(Sale_Amt) is the total sales within each polygon.

Could this be done using "Update Column"?

Hey David

I may need a bit more detail about your data to understand what you are trying to achieve.

You have a point table. Let's call it Points. It has some columns. Let's assume PointID and Sale_Amt.

You have a polygon table. Let's call it Polygons. It has some columns. Let's assume PolygonID.

You can create a SQL Join, where you join these data records:

Select Polygons.PolygonID, Points.PointID, Points.Sale_AmtWhere Polygons.OBJ Contains Points.OBJOrder By Polygons.PolygonID, Points.PointID

This will create a query with 3 columns: PolygonID, PointID, and Sale_Amt.

If a polygon has no points inside its boundary, the polygon will not appear in the result.

If a polygon has one point inside its boundary, the polygon will appear once in the result, also listing the point and the sales amount.

If a polygon has several points inside its boundary, the polygon will appear several times in the result. Once per point. It will also list the point and the sales amount.

Is this what you are looking for?

Cheers

Hello,

I am a new MapInfo Pro user and am attempting to aggregate data in a point file that fall within a polygon file. The points could fall within more than one polygon, in which case the data should be included in each polygon.

I tried the SQL select approach but it is appending the ID from the polygon file to each point that falls within.  Thank you for any guidance.