First, preparation work 1, install the plug-in
To facilitate drawing, we have installed OPENLAYERS,QUICKOSM two plugins.
How to install plug-ins, degrees Niang have the answer. Part of the tick is the installed plug-in:
Openlayers provides some open map data, and with this data, we don't have to start all over again, like Bing's satellite map, we can accurately plot the desired line, point, and multilateral type from satellite maps.
2. Create a project
When Qgis is open, a blank item is created by default, and the project's default coordinate system is 3857.
- establishing a coordinate system
Sometimes Qgis's own coordinate system may not be able to meet the needs of the business, so we need to customize our own coordinate system. Customize the coordinate system from the settings in the menu, and play the dialog box that defines the coordinates:
This is the coordinate definition of a proj.4 format, which is the center point of a point in Shanghai.
Second, start drawing
1. Create a layer
To create a layer dialog box:
For the choice of coordinate system, depends on your data, if it is a GPS device measurement points, you can directly select 4326, so that the map coordinates can be used directly. If you get coordinates from a network map such as a gold map, you select the appropriate projected coordinate system, or the feature location you create is incorrect.
2. Field definition
Fields are information other than geo-location information, such as the type of entity the line represents, for later query analysis. Specific to the needs of the set, not to repeat.
3. Drawing
First, set the layer to edit mode. Select the layer you want to modify, click the Yellow pencil icon in the toolbar, and when the icon is selected, you can draw on the current layer.
New features
Click "Add Features" to create a new feature. First point out the corresponding feature point on the map, then right-click the Pop-up Field dialog box, fill in the appropriate content, click OK to complete the drawing.
Moving features
You can drag and drop features on the map by selecting the features you want to move with the selection tool and then clicking the Move button.
4. Rendering
Style to show how features are rendered on the map.
Iii. Spatial Database
In order to improve the use of data, these spaces can be stored in the database system, the mainstream database now supports the storage of spatial data, such as MSSQLSERVER, Oracle and so on.
1, MSSqlserver
2. MySql
3. Oracle
Using QGIS to draw vector Traffic road map