The optimal scale of land cover products varies by different applications. Consequently, it needs the scale conversion of land cover products from the base resolution to the objective one. However, the scale effects accompanying the scale conversion often lead to information distortion of land cover products. The state-of-art patch-level research on scale effect, which is vulnerable to patch classification accuracy, often classifies the patches of land cover products into different types. Consequently, a cross-type scale effect model (CSEM) with Patch Area Ratio (PAR) is proposed in this study.The CSEM is aimed to explore further the effect mechanism of Patch Morphological Indexes (PMIs) on scale conversion, predict the areas of land classes in land cover products with specific scales, and provide a rationality evaluation for the scale conversion. First, a candidate index library is defined with seven indexes to describe the patch morphology based on patch size, shape, edge complexity, and internal connectivity. Then, a set of PMIs is defined by information metric techniques. The scale is incorporated into the PMIs by mathematical transformation. Moreover, the CSEM with PAR is constructed by associating the PMIs with PAR, calculated according to the patch areas before and after scale conversion.In this study, a 30 m land cover product from domestic satellites is used with the support of a National Key Research and Development Program to construct and validate the proposed CSEM. According to the experimental results, the CSEM fits the relationship among Filling, logRsr, and PAR: the logRsr is the main factor affecting the value of PAR when logRsr > -0.05, whereas Filling is the main factor on PAR while logRsr < -0.05. The prediction results show that the maximum prediction errors for the four land-cover types of forest, cropland, grassland, and impervious surface on 12 converted scales, varying from 90 m to 750 m with an interval of 60 m, are 0.056, 0.051, 0.051, and 0.053; their average prediction errors are 0.036, 0.033, 0.034, and 0.035, respectively.The results confirm that the CESM explores the effects of Filling and logRsr on PAR and reveals the effect mechanism during the scale conversion, providing instruction for subsequent research of other indexes. The proposed CSEM has satisfactory prediction accuracy for various area types in land cover products with specific scales. It can also provide theoretical guidance for scale conversion and production of land cover products.

land cover product;upscaling;scale effect;Patch area Ratio (PAR);Patch Morphology Index (PMI)