MapGIS和Section整合绘制边界约束下的属性等值线的方法——以堆积铝土矿为例

矿体作为一种特殊的地质体,其厚度等值线应受限于边界之内,这种约束特征用常规的计算机等值线绘制无法体现,为了表示边界线的约束特征,通过MapGIS和Section整合,可对边界线进行处理,提取子图元,赋予子图元边界线特有的相关属性,在属性结构相同的条件下使之与探矿工程子图元融合,然后采用Krining泛克立格法网格化模型绘制厚度等值线,形成的等值线均受限于边界线范围之内,真实的反映了矿体属性的本质,这种方法还可以绘制品位等其它属性等值线。作为约束条件的属性值必须是相同的,一般为零厚度、边界品位,边界含矿率等。矿体边界的属性值无法获得一致时,可通过外推边界的方法令其一致,具备此条件后即可进行属性等值线绘制。该方法实用、简捷。

Drawing of attribute contours under the condition of boundary constraint by integrating MapGIS and Section:a case study on cumulative bauxite

Orebody is a special geologic body,the isopachs of which should be limited to the boundaries,and this constraint feature cannot be represented by conventional computer contouring method.In order to show the constraint feature of boundary lines,this paper integrated MapGIS and Section in the treatment of bound-ary lines,and then it extracted sub-entities and assigned relative attributes of boundary lines to the sub-entities.The attributes were integrated with sub-entities of exploration engineering under the condition of same attribute structure,and thus the isopachs were drawn by applying Universal Kriging mesh model.The contours are limited to the boundary lines,and they truly reflect the essence of orebody attributes.This method can be used in the contouring of other attributes like grade etc.The attribute values as a constraint condition shall be identical and they normally include zero thickness,cut-off grade and cut-off ore coefficient.If the attribute values of the orebody boundaries are not consistent,they can be modified to become consistent through boundary extrapolation.Once these requirements are met,attribute contouring is feasible.This method is practical and convenient.