Resource: model_mask
| Resource | model_mask |
|---|---|
| Overview | Sets model data to mask a satellite image |
| Command Line | -mm=model,field,offset |
| Environment Variable | wxpmodmask |
| Possible Values | |
| Default Value | None or "ruc,init:2m_ag:temp:C,-10 if specified with no parameters |
The model mask is a way to make transparent parts of a satellite image that are perceived to be the ground. Since IR satellite images map pixel values to temperatures, it is possible to use surface temperature grids from a model to determine whether a pixel in the image is the ground and not a cloud.
If the model mask resource is specified with no parameters, the mask parameters are "ruc,init:2m_ag:temp:C,-10" which is the RUC model 2 meter above ground temperature analysis. An additional -10C offset is used to eliminate any possible variations between model and image data. For example, an offset of zero might not mask any of the image at all. Using 10C seems to eliminate any variances between IR temperatures and ground temperatures. So if the RUC surface temperature at a pixel location is 20C, the IR mask will only kick in for pixel values greater than 10C.
Last updated October 2013