I have a geodatabase that I am adding to a QGIS project. I read the documentation (below) but I don't understand what parameters I use for "a.the_geom" and "b.geom". Is there a way to clip with a bounding box? Or, what is the best way to reduce my huge data to just the small portion that I need?
16.5.9. Clipping To clip a subpart of your data you can use the ST_INTERSECT() function. To avoid empty geometries, use:
where not st_isempty(st_intersection(a.the_geom, b.the_geom))
I am using QGIS 2.8.2-Wien, a portable version. I'm running QGIS from an external hard drive connected via USB.
I've been opening a new project and then using Layer > Add Layer > Add Vector Layer > Source Type File -- and adding some of the files files that are in a .gdb geodatabase file.
It sounds like I can use the Select Features by Area or Single Click tool to select a rectangle and then I should be able to right-click or somehow save the selected area as a shapefile. However, when I select an area, as soon as I let go of the mouse button, I get the crash dump shown in the image below and QGIS shuts down. I will try using an older more stable version of QGIS.
The method I ended up using is probably only one of many ways to cut/crop/clip a small portion of data from a large data set. The first thing I did was switch to an older, stable, version of portable QGIS - 2.4.0-Chugiak. In the Layers Panel, I right-clicked on the layer, clicked Save-As... a "Save vector layer as..." window popped up which let me choose which format to save as from a drop-down menu at the top and there is a checkbox for Extent which allowed me to put in bounding box coordinates. I ended up with a shapefile with only the area that I wanted.