Standards /

WCPS-Manual / crsTransformExpr

The element performs reprojection of a coverage. For each axis, a separate CRS can be indicated; for any axis for which no CRS is indicated, no reprojection will be performed. For the resampling which usually is incurred the interpolation method and null resistance can be indicated per range field; for fields not mentioned the default will be applied.

NOTE changes the cell values (e.g., pixel radiometry).

NOTE A service may refuse to accept some CRS combinations (e.g., different CRSs handling for x and y axis).

NOTE As any coverage bearing a CRS beyond its image CRS is stored in some CRS, there will normally be a parameter combination which retrieves the coverage as stored, without any reprojection operation required.

Let

C1 be a coverageExpr,
m, n be integers with 1 ≤ m and 0 ≤ n,
a1, ... , am be pairwise distinct axisNames with ai ∈ axisNameSet(C1) for 1 ≤ i ≤ m,
crs1, ... , crsm be pairwise distinct crsNames with crsi ∈ crsList(C1) for 1 ≤ i ≤ m,
f1, ... , fn be pairwise distinct fieldNames,
it1, ... , itn be interpolationTypes,
nr1, ... , nrn be nullResistances with fi ∈ rangeFieldNames(C1)
and (iti,nri) ∈ interpolationSet(C1,fi) for 1 ≤ i ≤ n.

Then,

for any coverageExpr C2
where

C2  =  crsTransform(
       C1,
       { a1:crs1, ... , am:crsm } )
       { f1,(it1,nr1), ... , fn(itn,nrn) }
)

C2 is defined as follows: