The Characteristics and Methods of Map Printing Technology (I)

The map is a symbol of a social civilization and a microcosm of the political, economic, diplomatic and cultural education of a country. As an indispensable tool for mankind to understand the world, understand society, and transform the world, maps have been developed from the most basic place names and route inquiries to broader areas based on map analysis and processing. From government decision-making to municipal construction, from knowledge dissemination to corporate management, from mobile internet to e-commerce, and digital earth, digital China, and so on, no one can break away from the map. Especially with the advent of electronic maps, the emergence of networks, the development of geographic information systems, and global positioning systems, the application of maps as mapping terminal products has penetrated into every aspect of our lives, learning and work.

As a special carrier and a symbol of national sovereignty, maps are a special publication. Scientific and rigorous production of production processes is the key to ensuring that maps are adapted to market needs. Modern map printing is based on the disciplines of optics, color science, applied chemistry, macromolecules, materials science, photography, electronics, and information science. It belongs to the category of publishing and printing, but it has its own characteristics and Claim. Map printing is the copying of different types of map manuscripts, through different printing methods and techniques, to reproduce a large number of various forms of maps that are more beautiful and legible than the originals. With the development of modern science and technology, map printing uses many new technologies, new processes and new materials.

Compared with other publications, the plate printing of maps has its own characteristics, mainly in the following aspects:

1. Large print format. The size of the map is stipulated according to national technical standards, or it is stipulated according to special requirements in map compilation design, and cannot be arbitrarily divided. Generally, the topographic maps are divided by latitude and longitude according to the specifications, and the map outline size is about 60cm×44cm. The wall chart size is larger, and some use a few sheets or dozens of sheets to splicing. This is a feature not found in other printed materials.

2. High precision for copying. In map applications, data is sometimes acquired through topographic maps or other maps. Therefore, the size of map maps during and after copying must be within the allowable error range. Lines and symbols conform to the specifications of the legend or design. The content between two adjacent drawings must be correctly spliced, and the geometric accuracy of the map cannot be influenced by printing.

3. Print a color map with monochrome originals. Most of the map manuscripts provided for publication and printing are monochromatic. In the printing process, the color plots are referenced, and the plates are printed into color maps. Therefore, the procedures for copying, color separation, revision, and plate making are added. There are many difficulties.

4. More color printing. Although the map is monochrome, it is extremely inconvenient to use. Most maps are now printed in color. The national standard specifies that the 1:500,000 topographic map be printed in 6 colors; the 1:1 million topographic map should be printed in 9 colors; and the aeronautical map should be printed in 14 colors. Common maps, thematic maps, geological maps, mineral maps, etc. use more colors. Using more colors increases the difficulty of overprinting. At the same time, it requires that the hue and tonality between the spliced ​​frames be even and uniform. The difficulty is also a feature that other prints do not have.

5. Correct and correct errors and leaks in time. Because the content of the map is very complex, it represents a certain content from point to point. The loss of one point or the deviation of the first line may sometimes be misleading as a loss of territory. In the process of plate making, it is sometimes difficult to avoid individual errors, which requires us to make timely corrections and corrections on the film or plate.

So how do we see the maps printed out? Different eras have different technologies. The printing of maps has generally undergone several development processes as follows:

Copper engraving gravure printing map → lithographic printing plate → lithographic process plate printing map → photolithography → color desktop publishing system to draw maps → use GIS to draw maps.

The following mainly introduces two commonly used methods of drawing maps.

(1) Color desktop publishing system to draw a map

With the advent of computers, the traditional cartographic mapping method was broken, and substantial development was made in the quantitative analysis and evaluation of the earth resources. The map elements are quantified into simple numbers, which can be easily and qualitatively, quantitatively, and positionally analyzed by computers, and then the colors, symbols, and textual descriptions can be used to completely express the entities. Therefore, computer graphics technology is produced. The use of a desktop publishing system to produce maps was only developed in the past 10 years. Its powerful graphics editing software has a WYSIWYG graphical user interface that can basically meet the requirements of map editing and can get relatively good map works. The application of a color desktop publishing system, with computer and peripheral equipment as the core, and map cartography as the theory, integrates editing, design, compilation, plate making, and printing of the map, eliminating the need for intermediate painting, copying, and printing. , tear film and other operations to achieve a fully digital computer graphics process. The cartography process has been completely changed, the quality of mapping has been improved, manual work has been reduced, the labor intensity of cartographers has been reduced, the speed of charting has been accelerated, the cycle of photographing has been shortened, the cost has been reduced, and the variety and service area of ​​the map have been expanded.

The specific plate making process is to digitally scan the drawn map originals through a scanner or an electronic color separation machine to generate a TIFF map or a JGEG map, and then use the scanned graphics as a master, using Photoshop, Illustrator, Freehand, CorelDraw, etc. Professional software handles it. The path is checked against the outline of the line on the graph, and then the path is corrected. Then the color is filled, the text is written, the computer assists the color setting, and the drawn effect can be viewed on the display. After the inspection meets the requirements, the graphics workstation transmits the information to the color proofing system, outputs the color proofs, and can also transmit the Y, M, C, K four color separation negatives to the laser imagesetter for printing.

(2) Geographic Information System (GIS) mapping

Using the desktop publishing system to draw maps has improved the ability to edit maps, reformed the traditional drafting process, and formed a modern digital mapping process. Its development has played a powerful role in the promotion of GIS. The use of geographic information systems (GIS) to draw maps, compared with graphics, image editing and processing software, to further shorten the mapping cycle, reduce labor intensity, save material costs, improve data accuracy, ensure the quality of the map, and the data is convenient Updates can be edited and modified in a timely and dynamic manner. The introduction of GIS further provided modern and advanced technological means for map mapping. It is a technical revolution in the history of map mapping.

GIS is a large-scale intelligent software system integrating the most advanced graphics, image, geology, geography, remote sensing, surveying and mapping, artificial intelligence, and computer science technology. It is a space integrating digital mapping, database management, and space analysis. Information system. It is a technology and tool for storing and processing geographic information by computer. It encodes, inputs, processes, stores, and outputs various resource information and environmental parameters according to spatial distribution and geographical coordinates in a certain format and classification to meet application needs. Human-computer interaction information system. Through the operation and comprehensive analysis of multi-element data, it can conveniently and quickly output the required information in various forms such as graphics, images, numbers, etc. to meet the needs of various application fields.