The components of geological map spatial database mainly include: object class, element class, relationship class, comprehensive element class and element data set. The feature data sets that constitute the geological map spatial database are divided into three categories: basic feature data sets, comprehensive feature data sets and object data sets. Geological map feature data set is a collection of spatial reference system feature classes. In the geological map data model, it consists of entity classes of geological points, surfaces and lines. The spatial reference of feature dataset specifies the spatial reference system, spatial domain and accuracy, including coordinate system, projection system and height system. The collection of features with topological relations and the same geometric types and attributes is called geological map feature class. Points that make up a geological map are called geological map point feature classes, lines that make up a geological map are called geological map line feature classes, and surfaces that make up a geological map are called geological map surface feature classes. In addition, the geological map feature dataset should also contain attribute domains, which are rules for legal values of field types and are used to limit the values allowed in any specific attribute field of a table feature class or subtype. Each feature class or table has a set of attribute domains for different attributes and subtypes, and can be shared between feature classes and tables in a geodatabase.

Figure 5-2 Entity Relationship of Geological Map Spatial Database

The traditional geological map data model can not solve the above problems well, and the object-oriented technology and methods have brought us the dawn. The object-oriented data model takes a single spatial geological object as the basic unit of data organization and storage. Contrary to the topological data model, it takes independent and complete objects with geological significance as the basic unit to express geological space. A typical example is ESRI's geodatabase model. In the concrete organization and storage, the coordinate data and attribute data of the object (for example, a part of the topology is established and the topological relationship is also stored in the table) are stored in the relational database. Reorganizing and storing digital geological map data with object-oriented idea makes the expression of data closer to people's understanding of the objective world, and its semantic relationship and internal connection are more reasonable, which greatly enhances the ability of high-level geological spatial analysis. This model makes digital geological map independent of any given software and hardware structure.

The basic elements used in this paper include: geological boundary, dike (point), mineral place (point), occurrence and crater; The comprehensive element data set includes: alteration zone (surface); The target data set includes sedimentary (volcanic) lithostratigraphic units, intrusive lithostratigraphic units, metamorphic lithostratigraphic units, faults, plane waters and swamps.

1. The concept of database element class

The following elements are used to describe and define the feature class, object class and comprehensive feature class of geological map spatial database:

Entity name: Chinese name of entity data;

Feature class name: the Chinese name of the feature class;

Object Class Name: the Chinese name of the object class;

Name of comprehensive element class: Chinese name of comprehensive element class;

Coding of element objects and comprehensive element classes: standardized coding of data item names;

Spatial data type: pointing line and surface type;

Data type: refers to the type of data storage, generally including character type (C), single-precision numerical value (S), double-precision numerical value (D), long integer (L), plastic and so on. (1) The data types of special systems need to be clearly stated;

Relationship with other entities: indicates the relationship between the entity and other entities, such as topological relationship or dependency relationship;

Data storage length: the number of bytes stored in a specific system platform, which is the system default value;

Data display length: the length of data used for information expression, character data representing the number of characters, numerical data representing the number of digits before and after the decimal point, and data items with uncertain length should be stated;

Constraints: to determine whether to fill in data items, you can choose (O), required (M) and conditional required (C) according to the following three types of regulations; If it is a required item (M), you can fill in whether it is not empty;

Default value/initial value: determine the value of the data item in the initial state;

Scope: clearly give the scope of data items;

Data item description: describes the data item that needs further explanation. For data items with special expression formats, it is also necessary to explain here, such as the delimiter of multivalued expressions and the description of special symbols.

Primary key name: the name of the data item that identifies the uniqueness of the record and is associated with other entities;

Sub-keyword name: the name of the data item used together with the main keyword to identify the uniqueness of the record and to be associated with other entities;

Index key name: used to sort data items according to certain rules;

Annotation feature class coding: standardized coding of data item names of annotation feature classes.

2. Composition of element data set of geological map spatial database

It includes three categories: basic feature dataset, comprehensive feature dataset and object dataset. Geological map spatial database includes the classification of elements and objects, describes the contents of elements and objects, and the relationship between elements and objects.

3. Geological map class map based on geological database model

Figure 5-3 is a geological map class diagram based on the geological database model, which reflects the relationship between the geological map element class and the object class.

Figure 5-3 Geological Map Class Map of Geological Database Model

4. Definition of each element class field in spatial database.

According to the technical standard of geological survey of China Geological Survey, Standard for Building Digital Geological Map Spatial Database (DD2006-06), under the directory of ArcGIS 9.3, various element sets are established according to the data format of each element data specified in the standard, as shown in Table 5-3, and the data table structure and filling specifications are shown in Tables 5-4 to 5-1kloc-0/.

Table 5-3 List of Elements in Basic Database

Table 5-4 Surface Structure and Filling Specification of Sedimentary (Volcanic Rock)

Table 5-5 Intrusive Rock Surface Structure and Filling Specification

Table 5-6 Geological Boundary Layer Table Structure and Filling Specification

Table 5-7 Fault Layer Table Structure and Filling Specification

sequential

Table 5-8 Table Structure and Filling Description of Altered Layer

Table 5-9 Description of Structure and Filling of Volcanic Structure Layer

Table 5- 10 Ore Occurrence Layer Structure and Filling Specification Table

sequential

Table 5- 1 1 Rock Wall Structure Table and Filling Specification