[Doc] Repair invalid link of potsdam and vaihingen (#3042)

Repair invalid link of potsdam and vaihingen in docs

docs/en/user_guides/2_dataset_prepare.md

@@ -350,9 +350,10 @@ More details about LoveDA can be found [here](https://github.com/Junjue-Wang/Lov
 
 ## ISPRS Potsdam
 
-The [Potsdam](https://www2.isprs.org/commissions/comm2/wg4/benchmark/2d-sem-label-potsdam/) dataset is for urban semantic segmentation used in the 2D Semantic Labeling Contest - Potsdam.
+The [Potsdam](https://www.isprs.org/education/benchmarks/UrbanSemLab/2d-sem-label-potsdam.aspx) dataset is for urban semantic segmentation used in the 2D Semantic Labeling Contest - Potsdam.
 
-The dataset can be requested at the challenge [homepage](https://www2.isprs.org/commissions/comm2/wg4/benchmark/data-request-form/).
+The dataset can be requested at the challenge [homepage](https://www.isprs.org/education/benchmarks/UrbanSemLab/default.aspx).
+Or download on [BaiduNetdisk](https://pan.baidu.com/s/1K-cLVZnd1X7d8c26FQ-nGg?pwd=mseg)，password：mseg, [Google Drive](https://drive.google.com/drive/folders/1w3EJuyUGet6_qmLwGAWZ9vw5ogeG0zLz?usp=sharing) and [OpenDataLab](https://opendatalab.com/ISPRS_Potsdam/download).
 The '2_Ortho_RGB.zip' and '5_Labels_all_noBoundary.zip' are required.
 
 For Potsdam dataset, please run the following command to re-organize the dataset.
@@ -368,6 +369,7 @@ In our default setting, it will generate 3456 images for training and 2016 image
 The [Vaihingen](https://www2.isprs.org/commissions/comm2/wg4/benchmark/2d-sem-label-vaihingen/) dataset is for urban semantic segmentation used in the 2D Semantic Labeling Contest - Vaihingen.
 
 The dataset can be requested at the challenge [homepage](https://www2.isprs.org/commissions/comm2/wg4/benchmark/data-request-form/).
+Or [BaiduNetdisk](https://pan.baidu.com/s/109D3WLrLafsuYtLeerLiiA?pwd=mseg)，password：mseg, [Google Drive](https://drive.google.com/drive/folders/1w3NhvLVA2myVZqOn2pbiDXngNC7NTP_t?usp=sharing).
 The 'ISPRS_semantic_labeling_Vaihingen.zip' and 'ISPRS_semantic_labeling_Vaihingen_ground_truth_eroded_COMPLETE.zip' are required.
 
 For Vaihingen dataset, please run the following command to re-organize the dataset.

docs/zh_cn/user_guides/2_dataset_prepare.md

@@ -346,9 +346,10 @@ python tools/dataset_converters/loveda.py /path/to/loveDA
 
 ## ISPRS Potsdam
 
-[Potsdam](https://www2.isprs.org/commissions/comm2/wg4/benchmark/2d-sem-label-potsdam/) 城市语义分割数据集用于 2D 语义分割竞赛 —— Potsdam。
+[Potsdam](https://www.isprs.org/education/benchmarks/UrbanSemLab/2d-sem-label-potsdam.aspx) 城市语义分割数据集用于 2D 语义分割竞赛 —— Potsdam。
 
-数据集可以在竞赛[主页](https://www2.isprs.org/commissions/comm2/wg4/benchmark/data-request-form/)上请求获得。
+数据集可以在竞赛[主页](https://www.isprs.org/education/benchmarks/UrbanSemLab/default.aspx)上请求获得。
+这里也提供了[BaiduNetdisk](https://pan.baidu.com/s/1K-cLVZnd1X7d8c26FQ-nGg?pwd=mseg)，提取码：mseg、 [Google Drive](https://drive.google.com/drive/folders/1w3EJuyUGet6_qmLwGAWZ9vw5ogeG0zLz?usp=sharing)以及[OpenDataLab](https://opendatalab.com/ISPRS_Potsdam/download)。
 实验中需要下载 '2_Ortho_RGB.zip' 和 '5_Labels_all_noBoundary.zip'。
 
 对于 Potsdam 数据集，请运行以下命令调整数据集目录。
@@ -361,9 +362,10 @@ python tools/dataset_converters/potsdam.py /path/to/potsdam
 
 ## ISPRS Vaihingen
 
-[Vaihingen](https://www2.isprs.org/commissions/comm2/wg4/benchmark/2d-sem-label-vaihingen/) 城市语义分割数据集用于 2D 语义分割竞赛 —— Vaihingen。
+[Vaihingen](https://www.isprs.org/education/benchmarks/UrbanSemLab/2d-sem-label-vaihingen.aspx) 城市语义分割数据集用于 2D 语义分割竞赛 —— Vaihingen。
 
-数据集可以在竞赛[主页](https://www2.isprs.org/commissions/comm2/wg4/benchmark/data-request-form/)上请求获得。
+数据集可以在竞赛[主页](https://www.isprs.org/education/benchmarks/UrbanSemLab/default.aspx)上请求获得。
+这里也提供了[BaiduNetdisk](https://pan.baidu.com/s/109D3WLrLafsuYtLeerLiiA?pwd=mseg)，提取码：mseg 、 [Google Drive](https://drive.google.com/drive/folders/1w3NhvLVA2myVZqOn2pbiDXngNC7NTP_t?usp=sharing)。
 实验中需要下载 'ISPRS_semantic_labeling_Vaihingen.zip' 和 'ISPRS_semantic_labeling_Vaihingen_ground_truth_eroded_COMPLETE.zip'。
 
 对于 Vaihingen 数据集，请运行以下命令调整数据集目录。