在 Ubuntu 16.04 安装 QGIS 3.0 时出错 - 依赖包答案

【问题标题】：Error install QGIS 3.0 at Ubuntu 16.04 - Dependent packages在 Ubuntu 16.04 安装 QGIS 3.0 时出错 - 依赖包
【发布时间】：2020-08-06 01:36:44
【问题描述】：

我在 these tutorial 之后在 ubuntu 16.04 安装了 QGIS 2.18。

当我启动它时，会出现一条升级消息。

我卸载了 QGIS 2.18 以升级到 3.0 版。为此，我执行了this link 的步骤。

但是，当我尝试安装这些新版本时，遵循this another site，我收到以下错误消息：

lucas@lucas:~$ sudo apt-get install qgis python-qgis qgis-plugin-grass saga
[sudo] password for lucas: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 python-qgis : Depends: python-qgis-common (= 1:3.0.1+git20180411+dabf1c7+24xenial-ubuntugis) but it is not going to be installed
               Depends: libqgispython3.0.1 but it is not going to be installed
               Depends: libqgis-analysis3.0.1 but it is not going to be installed
               Depends: libqgis-core3.0.1 but it is not going to be installed
               Depends: libqgis-gui3.0.1 but it is not going to be installed
               Depends: libqgis-server3.0.1 but it is not going to be installed
 qgis : Depends: gdal-abi-2-2-2 but it is not installable
        Depends: libgdal20 (>= 1.8.0) but it is not installable
        Depends: libqgis-analysis3.0.1 but it is not going to be installed
        Depends: libqgis-app3.0.1 but it is not going to be installed
        Depends: libqgis-core3.0.1 but it is not going to be installed
        Depends: libqgis-gui3.0.1 but it is not going to be installed
        Depends: qgis-providers (= 1:3.0.1+git20180411+dabf1c7+24xenial-ubuntugis) but it is not going to be installed
 qgis-plugin-grass : Depends: qgis-provider-grass (= 1:3.0.1+git20180411+dabf1c7+24xenial-ubuntugis) but it is not going to be installed
                     Depends: libgdal20 (>= 1.8.0) but it is not installable
                     Depends: libqgis-app3.0.1 but it is not going to be installed
                     Depends: libqgis-core3.0.1 but it is not going to be installed
                     Depends: libqgis-gui3.0.1 but it is not going to be installed
                     Depends: libqgisgrass7-3.0.1 but it is not going to be installed
                     Depends: grass740 but it is not installable
E: Unable to correct problems, you have held broken packages.

我们将不胜感激。谢谢！

【问题讨论】：

是否可以暂时将系统语言切换为英语并重新发布错误？如果每个人都使用英语，那么 SO 效果最好。
谢谢@CollinM.Barrett，完成。

标签： ubuntu qgis

【解决方案1】：

我知道它已经 2 年多了，但我会发布它对我有用的东西，以防其他人发现这个问题。看起来aptitude 更好地处理依赖关系，所以我跑了：

$ sudo aptitude install qgis

需要注意的是，它给我的第一个选项是：

     Keep the following packages at their current version:
1)     python3-psycopg2 [Not Installed]                   
2)     python3-qgis [Not Installed]                       
3)     qgis [Not Installed]                               
4)     qgis-plugin-grass [Not Installed]                  



Accept this solution? [Y/n/q/?] n

我选择n是因为卸载这些包的解决方案并没有解决我的情况，然后提示：

The following actions will resolve these dependencies:

     Install the following packages:     
1)     python3-psycopg2 [2.8.4-2 (focal)]

那时我点击了y，因为安装该依赖项是我需要的解决方案。
我建议尝试使用aptitude，但要小心它不能神奇地解决问题，你必须注意并选择正确的路径。

【讨论】：