QGIS3.10 开发库安装及pygis测试

1. 下载32位安装包osgeo4w-setup-x86.exe

2. 运行osgeo4w-setup-x86.exe
   
   
   
   
   
   
   安装如下库：
   Desktop
   
   Libs
   

3. 安装结果目录
   

4. 打开C:\OSGeo4W\bin\qgis-ltr-bin.exe

加载shp文件，控制台测试pygis。

5. 独立脚本测试

设置环境变量

set PYTHONPATH=C:\OSGeo4W\apps\Python37\lib;C:\OSGeo4W\apps\Python37\lib\site-packages;C:\OSGeo4W\apps\qgis-ltr\python;

set QT_QPA_PLATFORM_PLUGIN_PATH=C:\OSGeo4W\apps\Qt5\plugins\platforms

set PATH=C:\OSGeo4W\bin;C:\OSGeo4W\apps\qgis-ltr\bin;C:\OSGeo4W\apps\Qt5\bin;%PATH%

或者更简单的执行：

C:\OSGeo4W\bin\python-qgis-ltr.bat   pygis.py

from qgis.core import *
# Supply path to qgis install location
QgsApplication.setPrefixPath(r".", True)

# Create a reference to the QgsApplication.  Setting the
# second argument to False disables the GUI.
qgs = QgsApplication([], False)

# Load providers
qgs.initQgis()

# Write your code here to load some layers, use processing
# algorithms, etc.

# Finally, exitQgis() is called to remove the
# provider and layer registries from memory
qgs.exitQgis()

使用C:\OSGeo4W\bin\python3.exe运行脚本。

6. 测试读写QGIS项目文件

from qgis.core import *
from qgis.core import QgsProject
import os

os.environ['GDAL_DATA'] = r'C:\OSGeo4W\share\gdal'
os.environ['PROJ_LIB'] = r'C:\OSGeo4W\share\proj'
# Supply path to qgis install location
QgsApplication.setPrefixPath(r"C:\OSGeo4W\bin", True)

# Create a reference to the QgsApplication.  Setting the
# second argument to False disables the GUI.
qgs = QgsApplication([], False)

# Load providers
qgs.initQgis()
# Get the project instance
project = QgsProject.instance()
# Print the current project file name (might be empty in case no projects have been loaded)
# print(project.fileName())

# Load another project
print(os.getcwd())
project.read('test.qgs')
# write 
project.write('my_new_qgis_project.qgs')
print(project.fileName())
qgs.exitQgis()

参考：https://docs.qgis.org/3.10/en/docs/pyqgis_developer_cookbook/intro.html#scripting-in-the-python-console