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NLCD 2011 40 Categories

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M

mahdad

New member
Hi All,

I would like to ask why NLCD 2011 and 2006 data sets have 40 categories? The original data sets only have 16 categories, except for Alaska (https://www.mrlc.gov/nlcd06_leg.php). The 40 categories for NLCD in the LANDUSE.TBL file seems to be the 24 categories of USGS 24 categories followed by NLCD original categories.

I am trying to use higher resolution of NLCD data (30 m). How do I have to reclassify my land type categories?

Thanks,
Mahdad
 
The first 20 NLCD landuse types are basically the same as MODIS. The extra ones are specific for NLCD. You don't need to reclassify land use categories when running with NLCD.

You can set

geog_data_res = ‘nlcd2006_30s+default’, ‘nlcd2006_30s+default’,

Please try to use WPS4.0
 
Thank you for your response Ming. My question is if I use only NLCD land cover data (geog_data_res = ‘nlcd2006_9s+nlcd2006_9s'), then how many lan cover categories are being written in LU_INDEX variable; 16 or 40?

Also, I need to use NLCD 30 meter resolution. So, I need to bring in NLCD original data in, based on Advanced Usage of the WRF
Preprocessing System NCAR tutorial (http://www2.mmm.ucar.edu/wrf/users/tutorial/201807/duda_wps_advanced.pdf). I am not sure if I need to reclassify them or if the first 24 categories are not considered in the 40 NLCD categories.
 
If you only use NLCD, then there should have 40 land cover categories .

I haven't processed the original NLCD data. Why are you concerned of the first 24 categories in the original NLCD? Are they different from those specified in vegparm.tbl?
 
The reason I am concerned is that NLCD has only 16 categories excluding the Alaska only categories (https://www.mrlc.gov/nlcd11_leg.php). So, I was confused that why there are the 24 categories of USGS land cover classifications in the NLCD table and then the 16 original categories of NLCD? Why should NLCD have 40 categories?

I have also checked the module_physics_init.F and noticed that only PXLSM can use the NLCD fine resolution data. So, does that mean Noah should not be used with NLCD data in WPS?
 
Noah and PXLSM both work with NLCD.

When people in LSM group incorporated NLCD into the WPS system, I guess they considered to make it consistent with USGS and MODIS and thus made some adjustments. That is why the NLCD data in WPS_GEOG contains 40 land use types.
 
Unfortunately I am not 100% sure of the original work that incorporated NLCD into WPS. The person who did this work left several yeas ago. I am sorry for the confusion.
 
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