Global Mapping for Global Environment
2. Proposal of Global Mapping
The Geographical survey Institute and the Ministry of Construction of Japan have worked out a plan of Global Mapping to be proposed to international community. 3) This project should be carried out through close international cooperation and the plan is a draft proposal to be further improved through discussions among professionals.
2.1 What should be made as the Global Map?
The plan is to prepare maps of the whole ground surface of the earth on one millionth scale both in digital and in analogue format within about five year.
The selection of map scale determines the character of the map. The reason we selected one millionth scale is that at smallest one millionth is necessary t represent important ground feature in
actual shape to grasp environmental conditions. Administrative boundaries of smallest unit such as village can be delineated with noticeable area on one millionth maps. This is necessary to plot statistical data one maps for sociological analyses and policy making.
Another reason is that most fundamental thematic information related to environment such as geology, vegetation, soil and hydrology is available from existing sources in one millionth scale. Consequently, we can make one millionght thematic maps in the second stage of the Global Mapping. These thematic maps with unified specifications will greatly contribute to the understanding of the global environmental conditions.
One millionth scale is also convenient when plotting grid data on maps because one kilometer on the ground corresponds to one millimeter on the map. The digital data of the Global Map can be used for various numerical simulations.
One the other hand, preparation of 1:200, 00 scale maps globally needs much more time and cost. Considering urgent necessity of unified maps of the whole world, we selected one millionth for the first stage of the Global Mapping project,
One may think new mapping on millionth scale is unnecessary because there already exist one millionth scale maps covering whole world such as Operational Navigation Chart (ONC) and World Map by Army Map Service (AMS). But ONC is a thematic map for aeronautical navigation and therefore the representative of ground features is not minute enough for one millionth scale. AMS maps are rather old. Therefore we consider it is necessary to make new one millionth scale maps. It is needless to say that when making the new maps we should make use of existing reliable resources as much as possible.
In our plan, the Global Map should contain the following entities; ground elevation, shorelines, rivers, lakes, marshes, vegetation, deserts, dunes, residential areas ( villages, towns, cities ), roads , railways, administrative boundaries and geographical names. The Global Map can be used as a general map and also as a base map for plotting other information. It is also possible to extract various kinds of environmental information from the map alone and to make out environmental conservation plan or development plan cover classification information. We can recognize environmentally important features by map reading and emphasize them by changing their map representation or draw boundary lines around them.
2.2 How to prepare the Global Map?
2.2.1 Technical Aspects
The Global maps will be made by compiling existing maps and geographical information resources where available. If there are no
appropriate maps, satellite imagery will be employed. For example, ground elevation is measured by using stereo pairs of SPOT satellite imagery. SPOT imagery is also used to delineate ground features. Other earth observation satellites which acquire stereo imagery can also be used besides SPOT. For land cover interpretation, imagery of Landsat or other satellites also can be employed. Making maps from satellite imagery has nowadays become well-established technology. (See Appendix.)
Digital cartographic data will be made by manual or automatic digitization of existing maps or compilation of existing digital data. For the areas where new mapping is required for the Global Map, the direct digital mapping technique will be employed. Geographical names will be collected in cooperation with surveying organizations of each country.
