5. Perl

  • 5.33. Perl reference

    A reference is a pointer. Perl reference is a scalar type that can point to variables, array...
    2023-10-20 23:00:04 UTC
  • 5.34. Perl formatted output

    Perl is a very powerful text data processing language. Perl can...
    2023-10-20 23:00:03 UTC
  • 5.35. Perl file operation

    Perl use a variable called the file handle type to manipulate the file. A file handle ...
    2023-10-20 23:00:04 UTC
  • 5.36. Perl directory operation

    Some standard functions for operating directories are listed below: Opendir DIRHANDLE, EXPR # Open direc...
    2023-10-20 23:00:03 UTC
  • 5.37. Perl error handling

    In the process of running the program, you will always encounter all kinds of errors, such as opening a file that does...
    2023-10-20 23:00:04 UTC
  • 5.38. Perl special variable

    The Perl language defines some special variables, usually prefixed with $ , @ ...
    2023-10-23 23:00:03 UTC
  • 5.39. Perl regular expression

    Regular expression (regular expression) describes a pattern of string matching, which can be used to check whether a s...
    2023-10-20 23:00:04 UTC
  • 5.40. Perl sends mail

    If your program runs on Linux/Unix, you can use it in Perl sendmail tool to send mail. ...
    2023-10-23 23:00:03 UTC
  • 5.41. Perl Socket programming

    Socket, also known as “sockets”, applications usually send requests to or reply to network requests through “sockets”,...
    2023-12-18 23:00:02 UTC
  • 5.42. Perl object oriented

    There are two different implementations of object-oriented programming in Perl: One is based on th...
    2023-10-20 23:00:03 UTC
  • 5.43. Perl database connection

    In this section, we will introduce you to the connection to the Perl database. In Perl 5 we can use the DBI m...
    2023-10-25 23:00:04 UTC
  • 5.44. Perl CGI programming

    5.44.1. What is CGI? # CGI is currently maintained by NCSA. NCSA define...
    2023-10-20 23:00:03 UTC
  • 5.45. Perl packages and modules

    Each package in Perl has a separate symbol table, which defines the syntax as follows: package mypack; ...
    2023-10-20 23:00:03 UTC
  • 5.46. Perl process management

    You can create processes in different ways in Perl. This tutorial will discuss the management of some process...
    2023-10-23 23:00:04 UTC
  • 5.47. Perl POD document

    POD (Plain Old Documentation) documents can be embedded in a module or script in Perl. POD is a simple and ea...
    2023-10-20 23:00:03 UTC
Principles, Technologies, and Methods of Geographic Information Systems  102

In recent years, Geographic Information Systems (GIS) have undergone rapid development in both theoretical and practical dimensions. GIS has been widely applied for modeling and decision-making support across various fields such as urban management, regional planning, and environmental remediation, establishing geographic information as a vital component of the information era. The introduction of the “Digital Earth” concept has further accelerated the advancement of GIS, which serves as its technical foundation. Concurrently, scholars have been dedicated to theoretical research in areas like spatial cognition, spatial data uncertainty, and the formalization of spatial relationships. This reflects the dual nature of GIS as both an applied technology and an academic discipline, with the two aspects forming a mutually reinforcing cycle of progress.