Unnecessary Resampling leading to poor pixel positioning

[staffordsmith83]

Dear Hongfaqiou,

there seems to be an issue with how TIFFImageryProvider maps the tiff values to the canvas. This occurs even when re-projection is not needed, e.g. for cogs in EPSG:4326 and EPSG:3857.

Using this Climate Data cog as an example (it is in EPSG:4326): https://nex-gddp-cmip6-cog.s3-us-west-2.amazonaws.com/daily/GFDL-CM4/ssp585/r1i1p1f1/pr/pr_day_GFDL-CM4_ssp585_r1i1p1f1_gr1_2015_01_25.tif

The data should look like this:

But TIFFImageryProvider renders it like this:

Note the following:

• The pixels are no longer square and appear to be resampled
• It does not retain the data integrity - we need users to be able to see the value of this scientific data at a single point on the globe.

Note in a more zoomed in example, how the pixels are clearly not square. This is TIFFImageryProvider in TerriaJS:

This is TIFFImageryProvider in your online demo:

Whereas the tru data is square pixels (shown in QGIS):

Please note, to be able to see what is happening at the pixel level we have changed the Cesium settings for _defaultMagnificationFilter and _defaultMinificationFilter to remove the blurring: https://github.com/TerriaJS/terriajs/blob/13fa4cfaabecdc82dff749836a1dcef602b0a1ae/lib/Models/Catalog/CatalogItems/CogCatalogItem.ts#L140-L141

If you like, we have put more details on the perceived error in out PR here: https://github.com/TerriaJS/terriajs/pull/7209

[hongfaqiu]

@staffordsmith83 I'm glad to see you continue to support TIFF in Terriajs. This issue is the same as #18 #22 , and I've been quite busy lately. I'll try to fix this issue next week, which seems to be related to resampling

[staffordsmith83]

Thats great, thanks @hongfaqiu, @nf-s watch this ticket