Introduction

MapInfo is a desktop geographic information system software from MapInfo Company in the United States, which is a desktop solution for data visualization and information mapping. It is based on the concept of maps and their applications, adopts office automation operations, integrates multiple database data, integrates computer mapping methods, uses geographic database technology, and incorporates geographic information system analysis functions, forming a highly practical and popular small software system that can be used by various industries. MapInfo means "Mapping+Information", which means map objects+attribute data.

Function Introduction

MapInfo is a powerful and easy-to-use desktop map information system that has basic operations such as graphic input and editing, graphic query and display, database operation, spatial analysis, and graphic output. The system adopts a menu driven graphical user interface and provides users with five toolbars (main toolbar, drawing toolbar, commonly used toolbar, ODBC toolbar, and MapBasic toolbar). The user enters a conversation state through commands on the menu bar or buttons on the toolbar. The viewing table windows provided by the system include a map window, a browsing window, a statistics window, and a layout window that helps output the design. The output results can be easily output to a printer or plotter.

Input of graphics

The input of graphics is to digitize or convert various map information data to obtain the basic graphic data organization of MapInfo - tables. Depending on the data source, a handheld digitizer, scanner input, or other standard data formats can be used to transfer. For example, AutoCAD's (. DXF and. DWG), Intergraph's (. DGN), and ESRI's ArcView Shape data.

The key points for digitizing input and editing maps using the drawing toolbar provided by MapInfo are:

1. Correctly set the coordinate system, projection, map direction, and units of the map

MapInfo supports multiple map projection methods. When users digitize a map, they first need to set the coordinate system and projection used for the map. Since most maps already indicate these two items in the legend, users can choose the coordinate system provided by MapInfo (stored in the text file MAPINFOW.PRJ), and modify MAPINFOW.PRJ to obtain a new coordinate system. To display a grid map in MapInfo, you must register the image and set a projection for it. Due to the fact that the process of projecting a map is usually not completely reversible, it is necessary to make a backup of the copy; Secondly, it is necessary to set the map units used based on the selected coordinate system. For example, maps in longitude/latitude projection will display map coordinates in degrees.

2. Set control point coordinates

In order to correctly interpret the position of the digitizer's moving head when tracking a map, it is necessary to set control point coordinate parameters on the map. Select at least 4 control points, the more control points there are, the more accurate the coordinate transformation from the digitization board to the map. The selected control points have better discreteness, such as not being on a straight line. You can add, modify, delete control points in the system, and save them in the workspace.

3. Drawing and editing tools

MapInfo has a complete set of drawing and editing tools. When editing a layer, first choose the "Layer Control" command from the map menu or use the "Layer Control" tool button to make the layer editable.

4. Using the method of reshaping geographical elements to edit maps

The map editing method can reshape areas, polylines, lines, arcs, and points on the map layer. This process is accomplished by moving, adding, and deleting nodes that define line segments, or by copying and pasting selected nodes to create new points, lines, and polylines. During the editing process, you can also use the mutual conversion function between regions and polylines to view the nodes of region objects, or use auxiliary editing functions such as merging, dividing, erasing, and stacking nodes.


5. Use the function of automatic map tracking

The function of automatically tracking objects is used to automatically track and obtain duplicate boundaries to avoid duplicate digitization. Turn on alignment (using the S key) to activate automatic tracking. Automatic tracking is not suitable for tracking shapes such as rectangles, arcs, ellipses, etc. made by drawing tools.

Data Table Management

In MapInfo, a database is called a table, and two types of tables can be used to establish, store, query, and display attribute data. One type is a data table, which can be divided into data tables containing graphical (map) objects and data tables without graphical objects, such as spreadsheets or external data tables; Another type of table is a grid table, which is an image that can only be displayed in the map window, without the table structure of records, fields, and indexes in the data table. We will only discuss the operations related to the data table here.

1. Transfer of external data

MapInfo can call dBASE databases, MSExcel spreadsheets, MS Access databases, Lotus1-2-3, and ASCll files. File type on the menu File ->; Open the "Open Table" window in and select. The external table that enters the system must be converted to a MapInfo table using the "Save As" command under the file menu before it can be edited.

2. Data Table Maintenance

In MapInfo, the structure of the data table can be directly changed, such as adding or deleting fields; Change the order, name, type, width, or index of fields; Set or determine the projection of the table from the dialog box; You can also delete data tables, rename data tables, and compact table structures to reduce disk space.

3. Operations on data tables

MapInfo's table operation commands (except for queries) are concentrated in the menu item "Table", mainly including:

(1) Create new tables, add, modify, display, and delete data records;

The update column command is used to quickly and visually update tables. First select the object and select Table ->from the menu; Update columns, fill in the dialog box for updating columns.

⑶ MapInfo provides many powerful aggregation functions to derive new information. The aggregation functions include:

Calculate the average value;

Count calculates the number of records in a group;

Minimum searches for the minimum value of all records in a group;

Maximum Finds the maximum value of all records in a group;

Sum calculates the sum of all recorded values in a group;

Weighted Average: When calculating the average, give a value a higher weight than another value;

The Proposal Sum adjusts the total calculation based on how much one object is within another object;

Proposal Average adjusts the average calculation based on how much of an object is within another object;

Proposition Weighted adjusts the weighted average calculation based on how much of an object is within another object.

(4) Geocoding is a way to display non mapped database records on a map, in order to view the map distribution of data. In order to observe data on a map, it is necessary to first assign positioning coordinates to each record, so that the data in the record matches the map. There are several different methods of geocoding, and here is an explanation of the "geocoding by boundary" method. Here, 'boundary' refers to a closed area or area. The essence of "geocoding by boundary" is to assign the X and Y coordinates of the boundary center to each data record in the table, so that the data records can be displayed with specified symbols at each boundary center in the map window. Once the geocoding is completed, the 'find' command can be used to locate individual records or objects.

Query function

The MapInfo system provides users with powerful and flexible query functions, known as the selection function in the system. By selecting, the corresponding data table information can be directly queried from the map, or the corresponding data and map information can be queried from the data table using the SQL Selection provided by the system. The system uses a temporary table (Selection Table) to store the selected results. For temporary tables, many operations for the basic table can also be performed, such as browsing, counting, copying, or editing the table, and new Selection can be further generated.

1. Select from the map

(1) Use the tools and menu commands in the main toolbar to select. The main selection tools are:

Any of the selection tools mentioned above can select multiple or all objects (to select multiple objects, hold down the Shift key and click on each object one by one); You can also select all objects by selecting the 'Select All' command from the 'Query' menu. Select the 'Select None' command to undo all selected objects. When you want to view the information of the selected data, you can call up a dialog box from the "New Browse Window" command and select the "Selection Table" of the selected data.

(2) Use tools to view map information, such as using information tools to view the corresponding data information of the hit map object; Use the legend tool to view the legend used in the current map; Use the ruler tool to calculate and display the distance between points on the map.

2. Use SQL Selection for selection

⑴ Select command

You can use the 'Select' command on the 'Query' menu to query a single basic table. Based on the conditions created by the user, select the results from the table and display the map objects of the selected records in the map window. The selected table, like other tables, can be browsed, queried, mapped, or used to create statistical charts. Create a result table using the 'Save As' command.


⑵ SQL selection command