Adding the data table to the already existing map data table

In the course of both vecorizing and importing apart from the graphical content (shp file) a data table is created automatically as well (dbf format file with the same name as the shp - see previous sub-chapters): in this a row is associated with every element. In both cases the addition of the data of a separate data table is possible and the process of this is discussed in this sub-chapter.

The first phase is the creation of the new map. This process has been discussed in detail in chapter 11 of the Geoinformatic Applications textbook as well as chapter 5 of the present textbook. Either the map is imported or vectorized in ArcView it is necessary to create an individual identification (ID) for every element (in a new

column) in the data table of the map generated automatically. This can be of any format (number, text or the combination of the two). Figure 7.8 shows the partially transformed table of the county map of Hungary:

• The unnecessary columns created in the course of import have been deleted (Entity, Layer, Elevation, thickness, Width, Color).

• Input of new data has been performed (Name, Area, Population) - for details on the process see chapter 11 of the Geoinformatic Applications textbook.

• The column containing the identifier (ID) essential for later additions has been created.

Figure 7.8: Original data table of the map

Requirements considering the identification code:

• Every object have to have an individual identification (doubling will be impossible).

• Every element have to be associated with an identification, the value cannot be empty.

• The identification can be of any format (number, text or the combination of the two). However, simplicity and clear structure are important. Therefore it is practical to avoid too many characters (for example the name of the county can be the identification in theory but it is not practical) and accented letters (they increase the possibility of mistyping).

In the next step the new data table to be added to the map is required. This has to include the new data and the individual identification code of the elements. Its creation can be performed in two ways: importing an already existing table or creating a new one.

For importing a data table, open the summarising window of the project (Figure 7.9) then open the file editing window using the Add button and select the database to be opened. This has to have the dbf format as the xls format (Excel) - at least in this software version - is not supported.

Figure 7.9: Data tables of the project

There is the possibility of creating a new data table as well in ArcView. For this, select the New button in the summarising window of the project (Figure 7.9). The new table is empty containing neither columns nor rows (Figure 7.10). It filling with data is performed as discussed before (chapter 11 of Geoinformatic Applications).

Figure 7.10: Creating a new data table

Figure 7.11 shows the already filled table. Required fields are the ID and the new data (the Székhely /Centre/

column in the present example). Apart from these, such data that are found in the data table of the map can be included as well (the Név /Name/ column in the present example): for better understanding this name column is present in the example, however, this may cause problems later (see later).

Figure 7.11: The new data table filled with data Important requirements regarding the new data table:

• Same number of data rows as in the data table of the map. Either more or less adding will not be possible.

• Identifications have to be the same. In case they do not match perfectly adding again will not be possible.

The next step is to add together the two tables. For this both tables have to be seen (do not close editing) and the column containing the identification has to be selected (caption is white with grey background) - in the case of our example this column is named ID. The table into which data are inserted has to be active (clicking on the caption will make its colour darker blue) - the data table of the map in the present example (Figure 7.8). Finally, by selecting the Table → Join command or the corresponding icon (icon 12 in Figure 7.12) joining is completed (Figure 7.13).

Figure 7.12: Icon row of the table

Figure 7.13: The joined table

Note that the inserted content cannot be modified (deleted, re-written) - this is indicated by that the caption of the inserted content remains italic when the table is made editable again (Table → Start Editing) indicating that this part of the table cannot be changed! Therefore in case we would like to avoid unnecessary doubling (for example the Név /Name/ is present in Figure 7.13) unnecessary columns have to be deleted before adding the tables together. (The Név /Name/ column was kept in the example only to visualize the process and logic of joining the two tables and make it controllable.)

Controlling questions Self controlling questions:

How is data attributed to objects in the course of digitizing in ArcView?

How can we obtain new attributes from the layer structure of the original (dwg format) file?

What is the procedure of adding to data tables together in ArcView?

Test:

In the case of displaying contour lines which is the best layer name type (regarding future conversions)?

a, Szintvonal_300_meter b, 300_m

c, 300

Which is the appropriate relation if we would like to acquire number data from the name of the layer containing the contour lines?