![]() This is entirely possible and how overviews work in geospatial we now just need to hack the overview method for the purposes of viewing our images in this manner. Great, we can export images with zoom rules honoured in the images, but what does it matter? Well, if we could “stack” these images in QGIS, have the resolution set to half of each other, and have them automatically turn on/off as users zoom, we would see the changes happening for each scale. So, from the example, users could export three images using the scale capturing the road width changes. When used properly, the exported image will honour the zoom rule for that scale. Sort of like taking snapshots of a project at different zoom levels and in different areas of interest. ‘Export to Image” allows users to export images from the project based on extent, resolution, and scale. With these rules in place, let’s next export a few images from capturing the style changes using the QGIS “Export to Image” function. With the roads layer in place, build a few varying road widths like: Let’s build a hypothetical QGIS project with a hillshade.tif, multiplied into an elevation DEM.tif gradient, and a vector roads layer placed over top. One is the QGIS “Export to Image” function and two, is a quirk of GDAL overviews, where an overview can read an overview of itself. The method relies on two processes readily available today. Upload COG to S3 and consume via webviewer or QGIS.Images converted to overview structure, with the lowest scale being the base of the overviews. ![]() “Export as Image” based on scale and zoom resolution.The process is devised as an alternative to raster tiling and explores the use of COGs as a raster-tile-esque format along with QGIS as a styling editor replacing Tilemill.įor those unfamiliar with the COG format, there is an excellent explanation here.įor COG uses in QGIS, users readers can look here. The following is a method for converting QGIS projects into stylized Cloud Optimised Geotiffs (COG)s.
0 Comments
Leave a Reply. |