projection extension best practices?

[cholmes]

I'd like to include proj shape and transform in one of the examples, and I realized I have no idea how to generate that.

Which makes me think we should have a best practice recommending the use of 'proj', and why it's good to include shape and transform - so that virtual catalogs don't have to open the geotiff (in my understanding). And how to generate it.

Is there a rasterio and/or gdal command that can get it for me easily?

[kylebarron]

They're both included as part of the rio info command. To use a 6-item transform you just discard the last three numbers.

> export AWS_REQUEST_PAYER="requester"
> rio info s3://usgs-landsat/collection02/level-2/standard/oli-tirs/2020/072/076/LC08_L2SR_072076_20201203_20201218_02_T2/LC08_L2SR_072076_20201203_20201218_02_T2_SR_B1.TIF | jq
{
  "blockxsize": 256,
  "blockysize": 256,
  "bounds": [
    142185,
    -2673615,
    369915,
    -2442885
  ],
  "colorinterp": [
    "gray"
  ],
  "compress": "deflate",
  "count": 1,
  "crs": "EPSG:32601",
  "descriptions": [
    null
  ],
  "driver": "GTiff",
  "dtype": "uint16",
  "height": 7691,
  "indexes": [
    1
  ],
  "interleave": "band",
  "lnglat": [
    -179.3819753343787,
    -23.115073747911566
  ],
  "mask_flags": [
    [
      "nodata"
    ]
  ],
  "nodata": 0,
  "res": [
    30,
    30
  ],
  "shape": [
    7691,
    7591
  ],
  "tiled": true,
  "transform": [
    30,
    0,
    142185,
    0,
    -30,
    -2442885,
    0,
    0,
    1
  ],
  "units": [
    null
  ],
  "width": 7591
}

[cholmes]

Sweet, thanks @kylebarron! That's easy. Just updated my example 1f1023e

Will write this up and add it. If there are other tools (gdal, etc) that others know let me know and I can add them too.

[kylebarron]

gdalinfo also prints related information, though it doesn't give the transform directly. From the gdalinfo output you could construct the transform using the origin and pixel size.

> gdalinfo /vsis3/usgs-landsat/collection02/level-2/standard/oli-tirs/2020/072/076/LC08_L2SR_072076_20201203_20201218_02_T2/LC08_L2SR_072076_20201203_20201218_02_T2_SR_B1.TIF
Driver: GTiff/GeoTIFF
Files: /vsis3/usgs-landsat/collection02/level-2/standard/oli-tirs/2020/072/076/LC08_L2SR_072076_20201203_20201218_02_T2/LC08_L2SR_072076_20201203_20201218_02_T2_SR_B1.TIF
Size is 7591, 7691
Coordinate System is:
PROJCRS["WGS 84 / UTM zone 1N",
    BASEGEOGCRS["WGS 84",
        DATUM["World Geodetic System 1984",
            ELLIPSOID["WGS 84",6378137,298.257223563,
                LENGTHUNIT["metre",1]]],
        PRIMEM["Greenwich",0,
            ANGLEUNIT["degree",0.0174532925199433]],
        ID["EPSG",4326]],
    CONVERSION["UTM zone 1N",
        METHOD["Transverse Mercator",
            ID["EPSG",9807]],
        PARAMETER["Latitude of natural origin",0,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8801]],
        PARAMETER["Longitude of natural origin",-177,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8802]],
        PARAMETER["Scale factor at natural origin",0.9996,
            SCALEUNIT["unity",1],
            ID["EPSG",8805]],
        PARAMETER["False easting",500000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8806]],
        PARAMETER["False northing",0,
            LENGTHUNIT["metre",1],
            ID["EPSG",8807]]],
    CS[Cartesian,2],
        AXIS["(E)",east,
            ORDER[1],
            LENGTHUNIT["metre",1]],
        AXIS["(N)",north,
            ORDER[2],
            LENGTHUNIT["metre",1]],
    USAGE[
        SCOPE["Engineering survey, topographic mapping."],
        AREA["Between 180°W and 174°W, northern hemisphere between equator and 84°N, onshore and offshore. Russian Federation; United States (USA) - Alaska (AK)."],
        BBOX[0,-180,84,-174]],
    ID["EPSG",32601]]
Data axis to CRS axis mapping: 1,2
Origin = (142185.000000000000000,-2442885.000000000000000)
Pixel Size = (30.000000000000000,-30.000000000000000)
Metadata:
  AREA_OR_POINT=Point
Image Structure Metadata:
  COMPRESSION=DEFLATE
  INTERLEAVE=BAND
Corner Coordinates:
Upper Left  (  142185.000,-2442885.000) (179d32' 1.37"E, 22d 3'14.84"S)
Lower Left  (  142185.000,-2673615.000) (179d28'47.50"E, 24d 8' 4.17"S)
Upper Right (  369915.000,-2442885.000) (178d15'39.41"W, 22d 5' 9.62"S)
Lower Right (  369915.000,-2673615.000) (178d16'50.09"W, 24d10'11.08"S)
Center      (  256050.000,-2558250.000) (179d22'55.11"W, 23d 6'54.27"S)
Band 1 Block=256x256 Type=UInt16, ColorInterp=Gray
  NoData Value=0
  Overviews: 3796x3846, 1898x1923, 949x962, 475x481, 238x241, 119x121