diff --git a/qgreenland/addons-readme.txt b/qgreenland/addons-readme.txt new file mode 100644 index 00000000..7cf89e0d --- /dev/null +++ b/qgreenland/addons-readme.txt @@ -0,0 +1,14 @@ +32-meter resolution ArcticDEM (digital elevation model): The Polar Geospatial +Center has provided a custom Greenland 32m resolution ArcticDEM for added +detail. Two download packages are provided for the v4.1 ArcitcDEM: + +* arcticdem_v4.1_32m_greenland_dem_only.zip: A ~4.1GB package containing only + the 32-m resolution DEM. + +* arcticdem_v4.1_32m_greenland_dem_full.zip: A ~9.5GB package containing the + 32-m resolution DEM and ancillary datasets (e.g., a "count" dataset giving the + number of contributing DEMs for each pixel). + +Download one of these add-on packages and place it in a suitable location in your +filesystem. Unzip the package and then follow the directions in the 'README.txt' +file included. diff --git a/qgreenland/arctic-dem-dem-only-readme.txt b/qgreenland/arctic-dem-dem-only-readme.txt new file mode 100644 index 00000000..9468582d --- /dev/null +++ b/qgreenland/arctic-dem-dem-only-readme.txt @@ -0,0 +1,54 @@ +------------------- +Getting Started: +------------------- + +This package consists of many small raster images (tiles) which together make up +a larger 32m resolution Arctic DEM mosaic of Greenland. To add this data to +QGIS, navigate in the **Menu Bar** to **Layer -> Add Layer -> Add Raster Layer** +and browse to and select the included .vrt file as the layer source. This .vrt +file references all of the individual tiles in the `tiles/` subdirectory, and +allows them all to be loaded as a single mosaiced raster layer in QGIS. More +information about VRTs can be found here: +https://gdal.org/drivers/raster/vrt.html. + + +------------------- +Building Overviews: +------------------- + +Because this dataset is large and consists of many smaller files, performance of +the layer after initially loading it into QGIS may be slow. We recommend that +users build raster overviews for this data, which will increase the rendering +speed when zooming in/out with the 32m Arctic DEM enabled. + +To build overviews in QGIS, navigate in the **Menu Bar** to **Raster -> +Miscellaneous -> Build Overviews (Pyramids)** . Select the 32m Arctic DEM as the +input layer, and then click **Run** (leave the rest of the parameters as their +defaults). This process will take several minutes and produce a new `.ovr` file +in the data directory. The new `.ovr` file is expected to be ~5.5GB in size, and +there is no need to interact with this new file. + + +------------------- +Styling this data: +------------------- + +For information on changing the symbology of raster layers in QGIS, see: + +* QGIS lesson on changing raster symbology: + https://docs.qgis.org/3.28/en/docs/training_manual/rasters/changing_symbology.html + +* QGIS documentation on raster symbology properties: + https://docs.qgis.org/3.28/en/docs/user_manual/working_with_raster/raster_properties.html#symbology-properties + + +------------------- +Citing this data: +------------------- + +The ArcticDEM dataset should be cited as follows: + +Porter, C., Howat, I., Noh, M.J., Husby, E., Khuvis, S., Danish, E., Tomko, K., +Gardiner, J., Negrete, A., Yadav, B., Klassen, J., Kelleher, C., Cloutier, M., +Bakker, J., Enos, J., Arnold, G., Bauer, G., and Morin, P., 2023, "ArcticDEM +- Mosaics, Version 4.1", https://doi.org/10.7910/DVN/3VDC4W diff --git a/qgreenland/arctic-dem-full-package-readme.txt b/qgreenland/arctic-dem-full-package-readme.txt new file mode 100644 index 00000000..b78c5b04 --- /dev/null +++ b/qgreenland/arctic-dem-full-package-readme.txt @@ -0,0 +1,76 @@ +------------------- +Getting Started: +------------------- + +This package contains the 32m Arctic DEM and ancillary data: + +* arcticdem_v4.1_32m_dem_greenland.vrt: 32-bit floating point elevation + raster. This is the primary DEM tile datafile. + +* arcticdem_v4.1_32m_browse_greenland.vrt: 32m DEM hillshade. + +* arcticdem_v4.1_32m_datamask_greenland.vrt: Raster indicating DEM pixels with + heights purely sourced from SETSM output (1) versus those that have been + filled/merged with another dataset or mask out as NoData in quality control + steps (0). + +* arcticdem_v4.1_32m_count_greenland.vrt: Number of contributing DEMs. + +* arcticdem_v4.1_32m_mad_greenland.vrt: Median absolute deviation of + contributing DEMs. + +* arcticdem_v4.1_32m_maxdate_greenland.vrt: Latest date of contributing DEMs in + days since Jan 1, 2000. + +* arcticdem_v4.1_32m_mindate_greenland.vrt: Earliest date of contributing DEMs + in days since Jan 1, 2000. + +Many small raster images (tiles) make up each of these layers to make a mosaic +of Greenland. To add this data to QGIS, navigate in the **Menu Bar** to **Layer +-> Add Layer -> Add Raster Layer** and browse to and select one of the included +.vrt files as the layer source. This .vrt file references all of the individual +tiles in the layer's associated `tiles/` subdirectory, and allows them all to be +loaded as a single mosaiced raster layer in QGIS. More information about VRTs +can be found here: https://gdal.org/drivers/raster/vrt.html. + + +------------------- +Building Overviews: +------------------- + +Because each layer is large and consists of many smaller files, performance of +each layer after initially loading it into QGIS may be slow. We recommend that +users build raster overviews for each layer, which will increase the rendering +speed when zooming in/out. + +To build overviews for a layer in QGIS, navigate in the **Menu Bar** to **Raster +-> Miscellaneous -> Build Overviews (Pyramids)** . Select the layer as the input +layer, and then click **Run** (leave the rest of the parameters as their +defaults). This process will take several minutes and produce a new `.ovr` file +in the data directory. The new `.ovr` file is expected to be several GB in size, +and there is no need to interact with this new file. + + +------------------- +Styling this data: +------------------- + +For information on changing the symbology of raster layers in QGIS, see: + +* QGIS lesson on changing raster symbology: + https://docs.qgis.org/3.28/en/docs/training_manual/rasters/changing_symbology.html + +* QGIS documentation on raster symbology properties: + https://docs.qgis.org/3.28/en/docs/user_manual/working_with_raster/raster_properties.html#symbology-properties + + +------------------- +Citing this data: +------------------- + +The ArcticDEM dataset should be cited as follows: + +Porter, C., Howat, I., Noh, M.J., Husby, E., Khuvis, S., Danish, E., Tomko, K., +Gardiner, J., Negrete, A., Yadav, B., Klassen, J., Kelleher, C., Cloutier, M., +Bakker, J., Enos, J., Arnold, G., Bauer, G., and Morin, P., 2023, "ArcticDEM +- Mosaics, Version 4.1", https://doi.org/10.7910/DVN/3VDC4W