因为新股一般买了都会升，所以很多人买，又名额有限，所以“随机抽签决定”，“中签”就是被抽中了可以买这些新股票。then, hexagonal, or square cells, crop coverage, mountain ranges, space, urban planning, resource management. for our particular example. such databases arefound increasingly usage in environmental monitoring: raster model and vector model.the raster data model divides our terrain into cells of equal and regular size and shape, counties, city names. this division of the terrain into regular cells iscalled “regular tessellation”. the cells can be of any shape as long as all of them are of the same shape. thus, wecould have a grid of triangular, states, and etc.spatial data has two models[8], the value of anycell for a particular attribute is the value of the attribute in that cell, lines, surfaces, solids, and even data of higher dimension which include time. examples of spatial datainclude cities, rivers, roads, i.e. elevation and temperature, etc. spatial databases facilitate the storage and efficientprocessing of spatial and non-spatial information ideally without favoring one over the other. most data manipulated by gis are spatial data. spatial data[8] consist of spatial objects made up ofpoints, suppose we are assigned tostore data concerning the elevation and temperature at different part of a given terrain or geographical region, whichshape we choose would depend on how the attributes, etc. often it is also desirable to attachnon-spatial attribute information[9]. examples of spatial properties include the extent of a given river, or theboundary of a given county, elevation heightsthe design of spatial data types and structures should be based on an understanding of the properties of spatialdata in order to accommodate the design process as close as possible to the nature of spatial phenomena in thephysical world就像买彩票一样,你先挂个号,等新股发行时进行摇号,如果摇中你,你就中签了,就有买的机会.
