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Figure 1 caption

Figure 1 | Geological map of Jinan spring area. Where, 1 = exposed and semi-exposed Ordovician limestone-Cambrian FengshanFormation limestone; 2 = Cambrian Changshan Formation limestone-Zhangxia Formation limestone; 3= magmatic rock; 4 = section; 5 = spring group; 6 = fault; 7 = river; 8 = the river recharge area; 9 = water sample collection point; 10 =place; 11=Discharge areas; 12=Direct recharge areas; 13=Indirect recharge areas.

Table 1 heading

Indirect recharge area, Direct recharge area, Discharge area

Projection pursuit algorithm (PPA) model of groundwater quality evaluation

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Under Equation (6), the sentence:

Thirdly: The optimization algorithm is used to search the best projection direction. The optimal projection direction of the evaluation index; that is, the optimal weight value, can be obtained by optimizing Equation (6).

Figure 2 key and caption

Figure 2 | Geological profile of Jinan spring area (I-I'). Where, 1 = Ordovician; 2¼ Cambrian Zhangxia formation; 3 = Cambrian Fengshan formation; 4 = Cambrian Gushan and Changshan formation; 5 = Cambrian Mantou formation; 6 = Limestone; 7 = Maristone; 8 = Olomitic Limestone; 9 = Oolitic Limestone; 10 = wormkalk; 11 = Diorite; 12 = Quaternary clay; 13 = streamline; 14 = springs; 15 = groundwater level; 16= Archean Eonothem Taishan Group metamorphic rock.

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