vortipurple.blogg.se

Go to Settings ► Custom Projections… and youĬlick on the Add new CRS button to create a newĪn interesting projection to use is called Van der Grinten I. You can also create your own projections. There are many more projections than just those included in QGIS by default. Follow Along: Creating Your Own Projection  You can now compare the old and new projections of the layer and see that theyĪre in two different CRS but they are still overlapping. The Save Vector Layer as… dialog now looks like this: Select WGS 84 / UTM zone 34S | EPSG:32734 from the list The Coordinate Reference System Selector dialog will Only the recent CRSs used will be shown in the drop-down menu.Ĭlick on the Select projection button next Navigate to exercise_data/ and specify the name of the new You will be shown the Save Vector Layer as… dialog. Select Export ► Save Features As… in the menu Right-click on the buildings layer in the Layers You can easily export the layer with another CRS.Īdd the buildings dataset from training_data.gpkg This means that a layer can have a different CRS from the project even Sometimes you need to export an existing dataset with another CRS.Īs we will see in the next lesson, if you need to make distanceĬalculations on layer, it is always better to have the layer in aīe aware that the ‘on the fly’ reprojection is related to the

Follow Along: Saving a Dataset to Another CRS  The layer is visible even if it has a different CRS from theĦ.1.3. You will find it as exercise_data/world/RSA.shp.Ī quick way to see its CRS is by hovering the mouse over the layer

“On the fly” reprojection is also used for combining datasets that areĪdd another vector layer to your map which has the data for South Zoom to a scale of 1:5 000 000 again, as before. Notice how the shape of South Africa changes.Īll projections work by changing the apparent shapes of objects on Select WGS 84 / NSIDC EASE-Grid 2.0 Global | EPSG:6933Įntry by clicking on it, and then click OK. Predefined Reference Systems field below. In the dialog that appears, type the word global into the You can change the CRS of the project by clicking on the The data itself is in another CRS, QGIS can project it as if it were in a CRS of Follow Along: “On the Fly” Reprojection īy default, QGIS reprojects data “on the fly”. Therefore, to keep the scale constant, we should reproject our data to To solve this, let’s use a Projected Coordinate System (PCS) instead.Ī PCS “projects” or converts the data in a way that makes allowance What this means for us, practically, is that there is no constant Scale of the objects that you see gets larger and larger. This means that, as you travel away from the equator on your map, the What this means on a map is that the longitude lines stay equally farĪpart from each other, even at the poles (where they are supposed to Occurs, similar to what would happen if you cut open a tennis ball and When you try to represent the sphere on a flat surface, distortion In a GCS, you are working on this sphere, but your screen is flat. These longitude lines are far apart at the equator, but they meet at It has lines running along it from North to South. To understand why, think about a globe of the Earth. One point that you zoomed into at 1:5 000 000, which was at theĪll around that point, the scale is different. Notice the scale changing? That’s because you are moving away from the Pan around the map while keeping an eye on the Scale While over South Africa, set this value to 1:5 000 000 Statusbar along the bottom of the screen. Try setting a scale in the Scale field, which is in the Zoom in to South Africa by using the Zoom In tool Then open the map of the world which you will find under This is a very common Geographic Coordinate System (GCS) for The CRS that all the data, as well as the map itself are in right now The goal for this lesson: To reproject and transform vector datasets. We have touched on this briefly before, but haven’t discussed what it Let us talk about Coordinate Reference Systems (CRSs) again. Lesson: Reprojecting and Transforming Data  Appendix: Contributing To This ManualĦ.1. Module: Spatial Database Concepts with PostGIS Module: Database Concepts with PostgreSQL Follow Along: Creating Your Own Projection Follow Along: Saving a Dataset to Another CRS Lesson: Reprojecting and Transforming Data Module: Creating and Exploring a Basic Map QGIS Desktop User Guide/Manual (QGIS 3.28).