There are times when you wish to define default values for one or more dimensions that are associated with a point. This list of dimensions can also be used when exporting the code prefixes so that they can be loaded onto survey instruments and taken into the field where the surveyor will be asked to enter the required dimensions for a code. The dimensions could be one of those already described in this chapter or it could be another dimension that is required for information purposes such as the depth of a manhole or species of a tree. The ninth page of the code prefix property sheet is called Fields and this allows you to do this. When selected, the property page shown below will be displayed.
The Fields group displays the available dimensions and allows you to add and remove them from the current code prefix. The Dimensions list shows the dimensions that have already been added. To add a new dimension, select the Add button and you will be asked to enter the new dimension name. To remove a field, select it in the list and select the Remove button. After a check is made, the dimension will be removed.
As you select each dimension, the fields in the remaining parts of the property page update themselves automatically.
The Default field in the Data group allows you enter a default for this dimension. This value will be used if no dimension has been attached to a point using this code prefix.
The Attributes groups contains the basic description of what the dimension represents.
The Type field specifies the data that is expected in the dimension. As far as n4ce is concerned, this setting is irrelevant as it is only interested in the dimension value itself. It is up to you what you do with the dimension in terms of text macros, etc. It does, however, have an effect when you are exporting the dimension in files of codes for upload to survey instruments.
Real - A number which may or may not have a decimal point.
Integer - A whole number which does not have a decimal point. These are often used as counters.
String - A string of text which contains alphanumeric and other characters.
The Description field allows you to enter a description for the dimension. When a dimension is added, the description will have the same name as that of the dimension.
The three radio buttons are used to constrain the value of the dimension and are described in the Constraining Dimensions article.
The Must Exist check button allows you to specify that a dimension is required at a point. Nothing is done if it does not exist. When carrying out a feature code report and a dimension of this type is found to be missing, it is flagged up in the report. The Internal Use check button defines that this field is for the internal use of n4ce only and should not be output to survey instrument code lists.