hexagonal gridqgisqgis-2.18
I followed this tutorial step by step.
However, when running the algorithm I get the following error:
"Horizontal spacing is too small for the covered area"
I'm using EPSG 3857 (WGS 84 Pseudo Mercator) and I'm trying to obtain a 1 HA just as stated in the question I linked. This happens whether I increase or decrease the grid extent or horizontal and vertical spacing. The same error occurs with other projections (4326, 32644, 3763)
Using QGIS 2.18.16
Not tested, but you could use a projected CRS to make your grid and then deproject the resulting shapefile to lat/lon geographic. This will distort the hexagons though.
In my part of the world (about 1-deg W, 51-deg N) 50 metres on the ground is roughly equivalent to 0.0004530 of a degree of latitude. 50 metres on the ground is also roughly equivalent to 0.0007170 of a degree of longitude. Using these values with the mmqgis plug-in it was possible to make a form of WGS84 lat/lon hexagon grid.
The attached picture shows such a grid, on a projected map image that is badly-distorted as a consequence of being reprojected on the fly to EPSG:4326.
But I would not trust such a grid as far as I could throw it. For what it's worth, my suggestion would be that if possible you change your project CRS to a projected one and use the mmqgis plug-in to make your hexagon grid using units of distance.
Nick.
A similar question was asked before: Is it possible to have another CRS in the status bar than used for the map? and the asker finally wrote this piece of code:
http://code.activestate.com/recipes/578692/
But I got stuck with it sometimes on startup.
You might be better of with the new QuickMapServices plugin, which can deal with different projections far better than the openlayers plugin.
Best Answer
These are the grid extent values you used:
These look like decimal degree values (ie, latitude and longitude). However, the selected coordinate system (EPSG 32644) uses meters.
You're telling QGIS to make a 500 meter wide grid inside an area that is 4.6 by 2.2 meters. A 500 meter wide hexagon doesn't fit inside 4.6 meters.
Solution: use grid extent values in meters
Use the Coordinate Capture tool to find the coordinates of the corners of your extent. Be sure to set the CRS of the Coordinate Capture tool to the same CRS that you'll use for the grid tool.