1. A display control device comprising:
a priority assigning unit for assigning a priority to each of multiple display areas arranged in a grid pattern;
a position information acquiring unit for acquiring position information indicating a position of each of one or more search targets existing in a search region;
a search target assigning unit for assigning a search target to a display area on a one-to-one basis in order of descending priority in accordance with a positional relationship between the display areas and the one or more search targets; and
a display control unit for generating an image for display in which a first icon image corresponding to the search target is arranged in the display area on a basis of an assignment result provided by the search target assigning unit, and for causing a display device to display a screen including the image for display.
2. The display control device according to claim 1, wherein the priority assigning unit assigns the priority in such a way that the priority gradually becomes lower with increasing distance from a reference position.
3. The display control device according to claim 2, wherein the search target assigning unit calculates a first vector indicating a direction of a center of each of the display areas with respect to the reference position, a second vector indicating a direction of each of the one or more search targets

with respect to the reference position, and a distance from the reference position to each of the one or more search targets, and assigns, to the display area in order of descending priority, the search target having a smallest evaluated value that depends on the distance thereof, out of yet-to-be-assigned search targets in each of which an angle value between the first vector and the second vector is less than an allowable angle value.
4. The display control device according to claim 2, wherein the display control unit causes the first icon image corresponding to the search target to be displayed in a different display mode depending on the distance from the reference position to the search target.
5. The display control device according to claim 4, wherein the display control unit causes the first icon image corresponding to the search target to be displayed in a different size or with a different degree of transparency depending on the distance from the reference position to the search target.
6. The display control device according to claim 2, wherein the first icon image includes multiple subicon images, and the display control unit causes one or more of the subicon images of the first icon image corresponding to the search target to be displayed in a different display mode depending on the distance from the reference position to the search target.
7. The display control device according to claim 6,

wherein the display control unit causes the one or more of the subicon images of the first icon image corresponding to the search target to be displayed in a different size or with a different degree of transparency depending on the distance from the reference position to the search target.
8. The display control device according to claim 2, wherein the display control unit causes the display device to display a screen including an inside of a region to be displayed of the image for display.
9. The display control device according to claim 8, wherein the region to be displayed is set to a region including the reference position.

10. The display control device according to claim 1, wherein the display control device comprises an attendant information acquiring unit for acquiring first attendant information indicating a type or state of each of the one or more search targets, and the display control unit generates an image for display in which a first icon image corresponding to the type or state of the search target is arranged in a display area.
11. The display control device according to claim 1, wherein the display control device comprises an attendant information acquiring unit for acquiring second attendant information indicating a connection relationship between search targets, and the display control unit generates an image for display including a linear image in which first icon images

are connected on a basis of the connection relationship.
12. The display control device according to claim 11, wherein the display control unit causes a part of the linear image overlapping a first icon image, to be displayed in a display mode different from that for another part of the linear image.
13. The display control device according to claim 12, wherein the display control unit causes the part of the linear image overlapping a first icon image, to be displayed as a broken line, and causes the other part to be displayed as a solid line.
14. The display control device according to claim 1, wherein the display areas include polygon-shaped display areas arranged in a polygonal grid pattern.
15. The display control device according to claim 14, wherein the display areas include square-shaped display areas arranged in a square grid pattern, hexagon-shaped display areas arranged in a hexagonal grid pattern, or triangle-shaped display areas arranged in a triangular grid pattern.
16. The display control device according to claim 14, wherein a size of one or more of the display areas differs from those of other display areas.
17. The display control device according to claim 14, wherein a shape of one or more of the display areas differs from those of other display areas.

18. The display control device according to claim 1, wherein the display control unit generates an image for display including a second icon image corresponding to a search target, and the second icon image is arranged on a basis of a position indicated by position information.
19. The display control device according to claim 18, wherein the display control unit causes the first icon image and the second icon image to be displayed in mutually different display modes.
20. A display control method comprising the steps of:
in a priority assigning unit, assigning a priority to each
of multiple display areas arranged in a grid pattern;
in a position information acquiring unit, acquiring position information indicating a position of each of one or more search targets existing in a search region;
in a search target assigning unit, assigning a search target to a display area on a one-to-one basis in order of descending priority in accordance with a positional relationship between the display areas and the one or more search targets; and
in a display control unit, generating an image for display in which a first icon image corresponding to a search target is arranged in a display area on a basis of an assignment result provided by the search target assigning unit, and causing a display device to display a screen including the image for display.