GeoWebCache under GeoServer

Few months back I wrote about GeoWebCache in my post “GeoWebCache under GeoNode“. Today I noticed a strange beheaviour from GeoWebCache as some of my newly added layers were not being cached.

If GeoWebCache is working properly, when ever a layer is published in GeoServer, by default a cached layer is created with the same name (one can check this by looking in Tile Layers list under Tile Caching GeoServer menu (left side)). Plus a folder is created with similar name to hold tiles in main cache path (e.g. …./geowebcache/workspace_tree_layer). Now if some one views this layer, GeoWebCache will cache tiles generated by GeoServer (and on next request, these pre-generated tiles will be served, if you want to know more read “Tile Caching and Seeding – GeoWebCache” ). Tiles are stores in their respective folder in main cached path.

Now back to my problem, when I checked cached folder (on server), I found that individual cached folders for each newly  created layer were being generated. But all of these folders were empty (no tiles inside any of the folders). Hmmmmmmmmmmm

As my last resort, I started looking at GeoServer logs and found “no such style” error again and again (it must have been generated when I was seeding these specific layers). I looked at style descriptors (SLDs) and found that when ever I assign SLDs to a specific workspace (no matter if it is the same one of the layer to which this SLD belongs to), the SLD is not available to GeoWebCache. When I removed the workspace information, the GeoWebCache found the SLD and worked perfectly.

Although, I solved the issue but I do not understand why under the same workspace, GeoWebCacbe cannot find style information. I am using GeoServer 2.4 (under GeoNode 2.0).

GeoExt 3 is around the corner

Web GIS components on client side depends on JavaScript. If you are following my Web GIS Development Step by Step series, you might have noticed a question about GUI and I explained that it is JavaScript Library called GeoExt. Well, for most of the web GIS applications, the maps, panels, table of contents, menus etc. are provided by libraries like OpenLayers, ExtJS and GeoExt (based on ExtJS).

Now the news is out that GeoExt version is also being developed. You can read more about it on GeoExt blog.

I will cover GeoExt in blog post 5 of my Step by Step web GIS development series.