Select the faces to be merged: Object → Merge, and the Data Aggregation dialog box will appear. The aggregation method is value → OK.
The segmentation method is similar to the above.
I. Overview:
In this lesson, you will use commands such as merge, set target and clear target to merge multiple regions into one large region. When merging objects, you should also practice how to aggregate data. When an area is deleted from a large area by using the erase command, data is decomposed from the large area. Finally, update the column with the Update Column command.
Second, the characteristics and concepts involved:
Data aggregation: The process of merging several separate map objects into one object. MapInfo calculates the column values of the new object according to the sum or average of the original object values.
Data decomposition: the process of dividing a map object into several smaller parts. In this process, MapInfo will divide the data related to the map object into smaller parts to match the new map object.
Third, the practical application:
When creating a region object, the Merge command performs a simple but important task to merge the selected polygons into the region object. A typical example of using this command is to merge some states into a sales region. Similarly, the erase and split commands allow you to erase and split objects from the sales area.
First, clean the desktop.
Select file > close all.
Users usually need to merge smaller objects together through aggregation to create new area objects. In this exercise, we will merge the states of the United States into four large regions.
Because you don't want to edit or modify the objects in the state table, you need to create a backup of the state table and use a new file.
A. select file > > open table.
B, select the state table.
C. click open.
D, select file > > save copy as ...
E. in the file name list box, enter ZONES. label ..
F. click save.
G. close the original form. Select file > close all.
Now, open a new file:
A. select file > open table.
B. select the area.
C. click open.
When merging states, we can also calculate the sum of the values in the sales area. In this example, MapInfo combines the calculation into the total sales of the states in the region 1990. To do this, you need to modify the table structure.
A. select table > > maintenance > > table structure.
B. Select an area from the drop-down list and click OK to display the Modify Table Structure dialog box.
C. click add field.
D in the field information section, enter a name in the name box.
E. determine the characters in the type box.
F, enter 15 in the width box.
G. delete all fields except Sales_ 1990 and the new field name just created. To do this, select each field you want to delete, and then click Delete Field.
H use the up button to move the name field to the top.
I. Click OK.
When MapInfo prompts you to confirm our changes, click OK.
Since the map object will be edited in the ZONES layer, we will add it to the current map and make it editable.
A. select map > > layer control.
B. click add.
C. Select an area from the drop-down list and click OK.
D, making the regional layer editable.
E. click ok.
Now, you are ready to create the first zone. First, choose the states that make up the region.
A hold down the Shift key and select 1 1 neighboring states in the western United States.
B. select object > > merge.
The Data Aggregation dialog box is displayed. Use this dialog box to name the new area and calculate the total sales.
C. Select a name in the target box, select a value under the aggregation method, and enter: Wostern in the text area.
D select sales-1990 in the destination box, and select Sum under the aggr collection method.
E. click ok to create the new object.
To view new information related to the new area, please use the Info button.
In order to add other adjacent states to the new area, the set target command is used together with the merge command.
A. select an area.
B, select Objects>Set Target, notice that the highlight has changed, and we tell MapInfo that the object will be changed.
C use the select button to select the states to be added to the western region.
D, select object > > merge.
You can preview the newly adjusted sales amount in the Data Summary dialog box.
E. click ok.
F, select object > clear target.
This new area now includes new states. We may want to delete a state from the zone, in which case we will use the erase command. We need to select a state from the original state table as the "cutting device", but first, we need to tell MapInfo which area will be modified.
A, select the area to be modified.
B, select object > > set target.
C. When using the selection tool to select the state to be deleted from the area, hold down the Ctrl key to select the object from the state table.
Select object > erase.
In the second half of this lesson, we need to ensure that the state will not be deleted, so we must resume the erase operation.
E, select its edit > > undo.
F. click ok.
Some applications require a region to be divided into two or more regions, so the SPLTT command is used.
A, select the area to be divided.
B. Select objects and set targets.
C to select a state from the state table, you may need to hold down the Ctrl key.
D, select object > > split.
E select a name from the field name box and a value from the decomposition method group box.
F. Select salcs- 1990 from the Field Name box, and select Area Ratio in the Decomposition Method group box.
G. click ok in the data decomposition dialog box.
Decomposition of data by area ratio method will lead to the proportional distribution of the above-mentioned data related to the whole area to each new? In this area.
Please note that the area is divided into smaller areas according to the number of continents initially selected.
Create three other areas to cover the rest of the United States. In order to provide different filling modes for regions, select Options > > Region Style to define specific line types and filling modes.
Now that we have merged the map objects in the ZONES table, we will compress the table.
A. select form > maintenance > package form.
B. click ok.
C. click save.
Since the compact table command will delete the area table from all windows, to display it again, select window > > new map and select the area from the dialog box.
Update column with
The Update Column command allows you to automatically change columns with great flexibility. You can transfer data from other tables or other columns in existing tables, change columns by aggregating some data, and create expressions or get additional information from existing data. These values can be placed in permanent columns or temporary columns created by MapInfo.
The US_CUST file will now be updated with the name of the sales area containing each consumer. Will we update it? TERR column, the information of sales area comes from ZONES table. Before you start, you usually need some initialization, and you need to extend the TERR column in the US_CUST file so that it can contain as many characters as the Name field in the ZONES table. To do this, we will use the table structure command mentioned in the last lesson 13.
Open the US_CUST file and modify its structure:
A. select table > maintenance > table structure.
B select CUST USA from the drop-down list, and then click ok.
C. select the TERR column from the field list.
D In the Field Information section, change the width to 15.
E. click ok.
Next, prepare to update the column:
A. select table > update column.
B select CUST USA from the drop-down list of "table to be updated".
C. select a region from the get values from table drop-down list.
D. select a value from the calculation drop-down list.
E. select a name from the belongs to drop-down list.
F. select TERR from the drop-down list of columns to update.
Note that when you specify a range (table from which to get values), MapInfo automatically enters "Add a new temporary column" in the Column to update box. We want to make sure that the column is identified as TERR.
When information is passed from one table to another, the Join button is activated. You need to confirm whether MapInfo has established the correct connection between the two files. Since there is no * * * column between CUST and each district, we will rely on geographical contact. In other words, if the ZONES object contains the US_CUST object, then the two tables are linked.
G. opt in.
H in the specify join dialog box, select the Where object from the table area. Select "Contains" in the list box below it, and then click "OK".
I. Click OK to exit the Update Columns dialog box.
A new browsing window has been created for CUST in the United States. Look at the TERR column, and each consumer in the browsing window contains the name of his sales area. Don't forget to help us, CUST.
Fourth, summary:
You learned how to use the Merge, Erase, and Split commands under the Object menu to create regions. The Merge command allows you to merge selected polygons into a larger polygon object. The Erase command deletes polygons from the region, while the Split command uses known polygons as cutting devices. Divide an area into two areas. In order to edit a region, it must be selected and set as the target. After editing, you must clear the target. Use the file > save table command to save the area. We can use the Update Column command to update columns based on information in other tables.