Dispersing Points Located in the Same Place - MapInfo_Pro - 2023

Depending on how you have geocoded your table, you may have several points that are placed at the same location, making it difficult to tell if you are viewing one point or many. For example, if you geocode a table of students by census tract, and view the results on your map, it appears that there is one dot at the center of each tract when there actually may be several there. To see all of your data, you may want to disperse the points over a small area. There are three methods for dispersing points: the Disperse Points tool (a tool that comes with MapInfo Pro), equal dispersion, and dispersion to the right.

Dispersing Points using the Equal Point Dispersion Method

The equal dispersion method disperses points at equal distances from the center.

1. First, select all of the points that have the same location. This can be done with either the Radius Selection or the Marquee Selection command. On the MAP tab, in the Selection group, click on a command in the selection list.
2. On the HOME tab, in the Windows group, click Tool Windows, and click MapBasic from the list, to open the MapBasic window.
3. Click in the MapBasic window, type RANDOMIZE, and press Enter.
4. Type the code below and press Enter:

   UPDATE SELECTION SET OBJ = CREATEPOINT(CENTROIDX(OBJ) +
   (0.01)/(COS(CENTROIDY(OBJ) * .01745)))*(RND(1) - .5), CENTROIDY(OBJ) +
   0.01*(RND(1) - .5))

Dispersing Points using the Dispersion to the Right Method

The dispersion to the right method disperses points to the right of the point.

1. First, select all of the points that have the same location. This can be done with either the Radius Selection, or Marquee Selection command. On the MAP tab, in the Selection group, click on a command in the selection list.
2. On the HOME tab, in the Windows group, click Tool Windows, and click MapBasic from the list, to open the MapBasic window.
3. Click in the MapBasic window, type RANDOMIZE, and press Enter.
4. Type the following and press Enter. The table will be automatically updated.

   UPDATE SELECTION SET OBJ = CREATEPOINT(CENTROIDX(OBJ) + 0.01 * RND(1),
   CENTROIDY(OBJ))

5. If the new Map window has not distributed the points satisfactorily, on the SPATIAL tab, in the Clipboard group, click Undo to restore the objects to their original positions.
6. To disperse points for the entire table, substitute your tablename in the above examples wherever it says SELECTION.