Point
- point data items are data items with a two-dimensional value-type (PointGroup) and a single coordinate for each entry.
- point-function is a function creating point data items.
The next topics on this page describe the point data item. The point function is described on the point-function page.
In the GeoDMS point data items are used for:
vector data
The feature-attribute of point vector-data always refers to one coordinate for each element in the domain-unit.
Vector point data is often read from a esri-shapefile or geopackage. X and Y attributes can also easily be read as numeric attributes from a data-source and combined with a point-function to a feature-attribute, as in the next example.
unit<uint32> residence
: StorageName = "=System/DbName"
, SqlString = "SELECT * FROM Residences ORDER BY id"
{
attribute<coord_rd> x;
attribute<coord_rd> y;
attribute<point_rd> geometry := point(x, y, point_rd);
}
The x and y attributes are read from the data source with as values unit coord_rd. The geometry data-item combines both x and y coordinate with the point function to create a two dimensional data item of coordinates. The values-unit of this geometry attribute is point_rd, defining the coordinate system.
Subitems of the location item can be configured to define multiple visualisation styles.
grid data
As the nature of grid data is two-dimensional, the identification of a grid cell in a Grid Domain is also two-dimensional.