Contents
What are the different types of layers in OpenLayers 2?
Layers are the ‘datasources’ in OpenLayers 2. OpenLayers 2 has two types of layers when operating in your application: base layers and overlays. This difference controls several aspects of how you interact with an OpenLayers 2 Map.
How to add a layer to a map?
As you can see, there are many ways to add a layer to the map. Case 1: Preferred when you know that layers will not change and only need to be loaded at the beginning Case 2: Address different cases.
When to use ol or ol.layer.group?
You may try to use an “ ol.layer.Group ” if your layers list starts to be complex. We may have m issed some other methods to add layer (s), they are more justifications for using a particular case? Feel free to comment!
How is the GML layer used in OpenLayers?
The GML layer is a vector layer subclass designed to read data from a file once and display it. It is ideal for working with many formats, not just GML, and can be configured to read other formats via the ‘format’ option on the layer. The simplest use case of the GML layer is simply to load a GML file.
Layers are the ‘datasources’ in OpenLayers 2. OpenLayers 2 has two types of layers when operating in your application: base layers and overlays. This difference controls several aspects of how you interact with an OpenLayers 2 Map. Base Layers are mutually exclusive layers, meaning only one can be enabled at any given time.
Why do I get wrong coordinates in OpenLayers?
If you have set a center in your map view, but don’t see a real change in visual output, chances are that you have provided the coordinates of the map center in the wrong (a non-matching) projection. As the default projection in OpenLayers is Web Mercator (see above), the coordinates for the center have to be provided in that projection.
Is there only one projection in OpenLayers map?
Every map that you’ll create with OpenLayers will have a view, and every view will have a projection. As the earth is three-dimensional and round but the 2D view of a map isn’t, we need a mathematical expression to represent it. Enter projections. There isn’t only one projection, but there are many common ones.
Why are there so many questions about OpenLayers?
Certain questions arise more often than others when users ask for help. This document tries to list some of the common questions that frequently get asked, e.g. on Stack Overflow. If you think a question (and naturally its answer) should be added here, feel free to ping us or to send a pull request enhancing this document.