A flow map helps determine the interaction between two or more points, representing the direction of movement by means of lines of variable widths according to their importance. Maps are popular tourist flow, migration and trade.
In this entry shows the process to map the flow of visitors obtained in March 2016 in the blog (unifying acolita.com and en.acolita.com), the following table is structured by country and number of visits, the SX and SY columns are the point of origin (Loja – Ecuador), and LONG_X and LAT_Y columns have the coordinates of the countries from which visits, note that the point of origin is repeated because it is the interaction center.
You can record the table as a delimited text file tab, or xls, open ArcMap and add the table from Add Data. Now create a line between the coordinates of origin and destination, for it to open the XY To Line tool located at:
ArcToolbox > Data Management Tools > Features
In the dialog box set as follows:
- Input Table, select the table.
- Output Feature Class, naming and directory.
- Start X Field, the field containing the values of the coordinates of origin on the X axis.
- Start Y Field, the field containing the values of the coordinates of origin on the Y axis
- End X Field, the field containing the values with the coordinates of the destination on the X axis.
- End Y Field, the field containing the values with the coordinates of the destination on the Y axis
- Line Type, select the geodetic method to build the line (GREAT_CIRCLE).
- Spatial Reference, select the reference system.
Once created lines flows in the layer properties to set the symbology that best fits, in this example first a Join (TMP_Flujo.txt and Visit_line) was performed to obtain the values of field visits in the layer lines then for graduated colors symbology it was used based on the number field visits. The rest is just carpentry.