Research on Basic Geographic Information Data Collection and Processing Method Based on ArcGis

1 Introduction

Collecting data for thematic or applied GIS (such as electric power GIS, telecom GIS and urban power grid management system) is the main application field of surveying and mapping technology at present. The closest mapping technology to GIS data collection is digital mapping technology. The biggest difference between them is that the former collects geometric data of geographical entities and also investigates their attribute information. In addition, in order to ensure the reliability and integrity of the collected data, the data collected for GIS must be tested and further processed before entering GIS. On the one hand, the spatial position, geometric shape and some attribute information of geographical entities need to refer to the geographical base map to check their correctness, such as whether the relative position relationship between some geographical entities and surrounding geographical elements is correct; On the other hand, the geometric figures and attribute information of some geographical entities can only be determined by referring to the geographical base map. For example, the geometric figures of some geographical entities can only be completely drawn by referring to the surrounding geographical elements, and the attribute information that is inconvenient to encode such as the location description of some geographical entities can only be better determined by referring to the geographical base map. Some geographic information needs to be collected directly from the geographic map. It can be seen that GIS data acquisition is far more complicated than digital mapping technology. According to the characteristics and requirements of thematic or applied GIS, it is of great significance to study its data acquisition technology.

At present, the most commonly used method to collect data in GIS such as electric power GIS, telecom GIS and urban power grid management system is to collect spatial data of geographical entities with total station or GPS, and fill in the attribute information table of geographical entities at the same time. This method is slow and easy to make mistakes, so the work efficiency is low. In addition, considering that AUTO CAD has powerful graphics drawing and editing functions, most of the indoor processing work of digital drawing is carried out under the software developed based on AUTO CAD, this paper proposes a digital acquisition method of g is data based on AUTO CAD with reference to digital drawing technology. Its workflow is shown in Table 1:

Table 1: Digital Collection Process of GIS Data Based on AUTO CAD

first step

Collect data on site

Field collection

Second step

Data transmission to AUTO CAD

Office treatment

Third step

Check and process data

Fourth step

Data transmission outside AUTO CAD

This method needs to solve the following three problems: first, the coding of geographical entity attribute information, second, the storage method of entity information in the graphic database of AUTO CAD, and third, the method of transmitting data from AUTO CAD to GIS.

2 attribute coding

Attribute information of geographical entities is information [1] used to describe the attributes of geographical entities (such as name, quality, quantity, grade, etc.). These attribute information can be divided into numbers (such as the area and length describing various quantitative attributes of entities) and characters (such as the name and nature of entities), in which the attribute information of characters can be divided into encodable (such as the nature and quality of entities) and uncoded.

When collecting data for GIS, in order to avoid filling in the questionnaire of entity attribute information and facilitate digital investigation, it is necessary to encode the encodable attribute information of the entity (the uncoded attribute information can be determined by referring to the geographical base map and the investigation attribute information when processing indoors), which is also the requirement of GIS to manage geographical information. The essence of coding is to convert the text attribute information into digital codes (codes) for computer processing, and it is also the main basis and means for g is to query information qualitatively [1].

Taking urban component measurement as an example, this paper introduces the method of entity attribute information coding. In addition to following the general principles of "scientificity, uniqueness, integrity, expansibility, applicability and standardization", attribute coding should also reduce the number of coding bits as much as possible to facilitate memory and field use. For example, the ownership or management department of the urban part can refer to table 1 for coding.

Table 2 Code Table of Urban Parts Ownership Department

serial number

Unit category

Main types

Unit coding

Name of professional department

manage

0 1

Urban management team

…

Public institutions

0 1

Landscaping bureau

…

three

enterprise units

three

0 1

Water supply company

…

In order to save computer space, sometimes two attributes can be combined and coded, and one number can be used to represent the two attributes. For example, the status and current situation of components refer to the current usage situation, which can be divided into four situations: intact, damaged, occupied and lost. The current status refers to whether the part is in use or abandoned. Please refer to the following table to compile the code.

Table 3 Component Potential and Status Code Table

status

situation

encode

colour

in service

in perfect nick

red

in service

Broken or damaged

yellow

in service