Run Shape Type

We will demonstrate the Gen-Vx-Mask "shape" masking type using freely available shapefiles from Natural Earth. While multiple resolutions are provided, we'll use the coarsest version for this example since it's the smallest in size.

Download the Natural Earth administrative shapefiles for countries boundaries.

cd ${METPLUS_TUTORIAL_DIR}/output/met_output/gen_vx_mask
mkdir ne_shapefiles; cd ne_shapefiles
wget https://www.naturalearthdata.com/http//www.naturalearthdata.com/download/110m/cultural/ne_110m_admin_0_countries.zip
unzip ne_110m_admin_0_countries.zip

Run gen_vx_mask to define the mask for the USA (index 4).

gen_vx_mask G004 ne_110m_admin_0_countries.shp G004_USA_mask.nc -name USA -type shape -shapeno 4 -v 3

Re-run to compute the union with Canada (index 3).

gen_vx_mask G004_USA_mask.nc ne_110m_admin_0_countries.shp G004_USA_Canda_mask.nc -name USA_Canada -type shape -shapeno 3 -union -v 3

Re-run to add Mexico (index 27).

gen_vx_mask G004_USA_Canda_mask.nc ne_110m_admin_0_countries.shp G004_North_America_mask.nc -name North_America -type shape -shapeno 27 -union -v 3

The result is good but not perfect. There are a few missing grid points along the boundary. But this demonstrates how the tool works. Consider re-running all three commands again, but this time use the "-value" command line option to define the mask value to be written. Just make "-value" match the "-shapeno" option (.e.g. -value 4 for USA, -value 3 for Canada, and -value 27, for Mexico). What impact does that have on the result?

Next, we'll take a look at the functionality that Grid-Stat offers.

jpresto Fri, 12/17/2021 - 12:59