Identify crops and placing crop cover in land cover map

[joe999]

Hello,

 

I don't know if the topic will fall under GIS or remote sensing, but I am trying to incorporate crop maps which are 10 KM resolution with 1KM crop land cover maps.  How would I use remote sensing to identify the type of crop.  Are there any steps involved.  

 

The GIS aspect would be able to disaggregate the data, if I have information on percentages for each 10 km cell.  Would anyone have any suggestions on how this should be performed.

 

Admin:  I apologize if this topic falls under multiple forums, I just wasn't too sure where to post it.

 

Thanks.

 

Shaffiq

[mamadouba]

There are two schools of thought on this topic, deriving crop types by phenology or spatial downscaling.

 

Phenology metrics: The researcher either develops or applies existing land cover maps to derive long-term time series statistics from vegetation indices (e.g. 250-meter MODIS NDVI).  These phenological temporal profiles can be used to derive broad category crop types, winter vs. summer crops.  For example, winter grains (wheat and barley) in the Middle East will show a start-of-season (emergence) around January to February, the greenup will peak around April, and the profile will begin to drop in May-June signifying senescence and harvest.  If the region is double-cropped, the same principles can apply to the summer crops.  Knowing the specific crop calendars will serve as guides.  There are a number of peer-reviewed research journals explaining variations of this approach.

 

Spatial downscaling:  This seems more in line with your current resources.  This requires allocating or disaggregating information to a different scale (i.e. 10KM to 1KM).  Cross-entropy and other techniques apply.  http://www2.toulouse.inra.fr/lerna/chercheurs/thomas/projets/ADD%20WP%203%20(RChakir)%20v2.pdf

[joe999]

Thanks so much