Add bilinear resample method & supporting TypeScript types (plus bugfixes) #34
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Replaced the built-in resample method with a copy of geotiff.js's bilinear resample function, to see if it would improve accuracy. It does not. Also added TypeScript annotations to requestImage and supporting code so it'd be easier to understand what was going on.
Added optional resampleMethod prop to constructor options, to choose between existing resampleData function and the new geotiff.js based bilinear resampling. Added BBox type to reduce duplicated typings of [num,num,num,num]. Also found and fixed a few bugs, namely: - Missing blue in stringColorToRgba() - Filled in nodata value in reprojection() - Swapped sourceWidth & targetWidth in reprojection() - In the last commit, but I forgot to mention it
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@TheMrCam What a great update! Thank you for your contribution! |
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Dear @TheMrCam I've added a buffer parameter for the bilinear interpolation resampling method, which can ensure continuous changes at the tile seams. However, the buffer parameter has not yet been adjusted in the reprojection method, and the rendering performance doesn't seem to have changed much. I'll need to address this problem when I have some time. Additionally, I've moved the resampleMethod parameter into the renderOptions. |
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Overview
For accurately displaying elevation model rasters (DEM), we'd prefer bilinear resampling over the current nearest neighbor implementation. This PR adds the option to use bilinear resampling with the
resampleMethod: 'bilinear'constructor option.To help own understanding of what was going on, I removed a lot of the TypeScript ambiguity to the
resampleandreprojectionareas of the code. I removed (most) casts toany, mostly with geotiff.js'sTypedArrayand variations. I also fixed a few bugs while I was investigating the codebase.Primary changes
resampleBilinearmethod, based on the geotiff.js implementationresampleMethodtoTIFFImageryProviderOptionscopyNewSizeutility to maintainTypedArraytype throughout transformationsBugfixes
sourceWidth&targetWidthinreprojection()stringColorToRgba()usedgreenforblue, potentially missing a whole band of data.any(in the code I was looking at)ResampleDataOptions