Abstract:Compilation of landcover maps needs high qualified landcover data with precise classification. Traditional techniques to obtain these have the problem of high cost, heavy workload and unsatisfied results. To this end, a semantic segmentation method was proposed for unmanned aerial vehicle (UAV) images, which was used to segment and classify different types of land areas to obtain landcover data. Firstly, the UAV images were annotated which contained various land use types at pixel level according to the latest national standards, and the highresolution complex landcover image data set of UAV was established. Then, several significant improvements based on original design of semantic segmentation model DeepLabV3+ were made, including replacing the original backbone network Xception+ with the deep residual network ResNet+; adding joint upsampling unit after backbone network to enhance the encoder’s capability of information transfer and conduct preliminary upsampling; adjusting dilated rates of atrous spatial pyramid pooling (ASPP) unit to smaller ones and removing global pooling connection of the module; and improving the decoder by fusing more lowlevel features. Finally, the models were trained and tested on the UAV highresolution landcover dataset. The presented model achieved good experimental results with pixel accuracy of 95.06% and mean intersectionoverunion of 81.22% on the test set, which was 14.55 percentage points and 25.49 percentage points higher than that of the original DeepLabV3+ model respectively. The proposed method was also superior to the commonly used semantic segmentation methods FCN-8S (pixel accuracy was 32.39%, mean intersectionoverunion was 8.39%) and PSPNet (pixel accuracy was 87.50%, mean intersectionoverunion was 50.75%). The results showed that the proposed method can obtain more accurate landcover data and meet the needs of compiling fine landcover maps.