[postgis-tickets] [PostGIS] #2312: [raster] st_circle

[PostGIS]

#2312: [raster] st_circle
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 Reporter:  nclay        |       Owner:  dustymugs     
     Type:  enhancement  |      Status:  new           
 Priority:  medium       |   Milestone:  PostGIS Future
Component:  raster       |     Version:  trunk         
 Keywords:               |  
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Comment(by nclay):

 I've implemented st_circle in plpgsql and I am not impressed with its
 speed.

 So I am considering modifying nMapAlgebra to accept a mask argument. A
 mask would have the following properties: height,width, and weighted. If
 weighted is marked the mask is used to weight the pixel values as: pixval
 * mask. If it is not marked then the pixel values are returned where the
 mask is not null.

 To this end, I think it would be best to modify nMapAlgebra by replacing
 rt_band_get_pixel with rt_band_mask_get_pixel this function would consider
 the mask when returning pixel values. Do you (dustymugs) have any
 suggestions or objections? Should I open another ticket for this?


 {{{

 struct rt_mask_t {
   uint16_t width;
   uint16_t height;
   bool weighted;
   void** data;
 };

 /**
  * Get Pixel from band with consideration of a masked extent returning
 nodata value
  * if mask position is null.
  *@param band : the band to get the pixel value from
  *@param mask : the mask to mask the band with
  *@param extent : array of values containing the bounds of the mask.
  *@param x : the x coordinate of the band to be sampled
  *@param y : the y coordinate of the band to be sampled
  *@param pixval : the value of the band to be returned
  *@param nodata : flag to indicate that the value is nodata or masked
  *
  *@return ES_ERROR on error
  */
 int rt_band_mask_get_pixel(rt_band band,
                            rt_mask mask,
                            int** extent,
                            int x,
                            int y,
                            double *pixval,
                            int* nodata
 )
 }}}

 Thanks,

 Nathan

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/2312#comment:12>
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