WCS vignette with error.

[ecor]

I rerun automatically all the chunks of the WCS vignette and the following error occurs (SEE BELOW) , when the SpatRast object should have been returned. Is it an issue of the WCS URL used?
Thank you
Best
Emanuele @ecor

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Restarting R session... > knitr::opts_chunk$set(echo = TRUE,eval=TRUE) > > library(ows4R) Loading ISO 19139 XML schemas... Loading ISO 19115 codelists... > > WCS <- WCSClient$new("https://ows.rasdaman.org/rasdaman/ows", "2.1.0", logger = "INFO") [ows4R][INFO] OWSGetCapabilities - Fetching https://ows.rasdaman.org/rasdaman/ows?service=WCS&version=2.1.0&request=GetCapabilities \|=============================================================================================================\| 100% > caps <- WCS$getCapabilities() > chla <- caps$findCoverageSummaryById("AverageChloroColorScaled", exact = T) > chla_des <- cov$getDescription() Error in cov$getDescription : object of type 'closure' is not subsettable > chla Inherits from: Public: attrs: list BoundingBox: list clone: function (deep = FALSE) CoverageId: AverageChloroColorScaled CoverageSubtype: ReferenceableGridCoverage CoverageSubtypeParent: NULL defaults: list element: AbstractObject encode: function (addNS = TRUE, geometa_validate = TRUE, geometa_inspire = FALSE, ERROR: function (text) getBoundingBox: function () getClass: function () getClassName: function () getCoverage: function (bbox = NULL, crs = NULL, time = NULL, elevation = NULL, getCoverageStack: function (time = NULL, elevation = NULL, bbox = NULL, filename_handler = NULL, getDescription: function () getDimensions: function () getId: function () getNamespaceDefinition: function (recursive = FALSE) getSubtype: function () getSubtypeParent: function () getWGS84BoundingBox: function () INFO: function (text) initialize: function (xmlObj, capabilities, serviceVersion, owsVersion, logger = NULL) isFieldInheritedFrom: function (field) logger: function (type, text) loggerType: INFO namespace: OWSNamespace, R6 verbose.debug: FALSE verbose.info: TRUE WARN: function (text) WGS84BoundingBox: list wrap: FALSE Private: capabilities: WCSCapabilities, OWSCapabilities, OGCAbstractObject, R6 description: NULL dimensions: NULL fetchCoverageSummary: function (xmlObj, serviceVersion, owsVersion) fromComplexTypes: function (value) owsVersion: 2.0 system_fields: verbose.info verbose.debug loggerType wrap element names ... url: https://ows.rasdaman.org/rasdaman/ows version: 2.1.0 xmlElement: AbstractObject xmlExtraNamespaces: NULL xmlNamespacePrefix: OWS xmlNodeToCharacter: function (x, ..., indent = "", tagSeparator = "\n") Restarting R session... > knitr::opts_chunk$set(echo = TRUE,eval=TRUE) > > library(ows4R) > > WCS <- WCSClient$new("https://ows.rasdaman.org/rasdaman/ows", "2.1.0", logger = "INFO") [ows4R][INFO] OWSGetCapabilities - Fetching https://ows.rasdaman.org/rasdaman/ows?service=WCS&version=2.1.0&request=GetCapabilities \|=============================================================================================================\| 100% > caps <- WCS$getCapabilities() > chla <- caps$findCoverageSummaryById("AverageChloroColorScaled", exact = T) > chla_des <- WCS$describeCoverage("AverageChloroColorScaled") [ows4R][INFO] WCSClient - Fetching coverageSummary description for 'AverageChloroColorScaled' ... [ows4R][INFO] WCSDescribeCoverage - Fetching https://ows.rasdaman.org/rasdaman/ows?service=WCS&version=2.1.0&coverageId=AverageChloroColorScaled&request=DescribeCoverage \|=============================================================================================================\| 100% Loading required package: sf Linking to GEOS 3.10.2, GDAL 3.4.3, PROJ 8.2.0; sf_use_s2() is FALSE > chla_dims <- chla$getDimensions() [ows4R][INFO] WCSCoverageSummary - Fetching Coverage envelope dimensions by CRS interpretation Unknown IO errorfailed to load external entity "http://crs.rasdaman.com/def/crs-compound?1=http://crs.rasdaman.com/def/crs/OGC/0/AnsiDate&2=http://crs.rasdaman.com/def/crs/EPSG/0/4326" Error : 1: Unknown IO error2: failed to load external entity "http://crs.rasdaman.com/def/crs-compound?1=http://crs.rasdaman.com/def/crs/OGC/0/AnsiDate&2=http://crs.rasdaman.com/def/crs/EPSG/0/4326" [ows4R][ERROR] WCSCoverageSummary - Error during CRS interpretation for srsName = 'http://crs.rasdaman.com/def/crs-compound?1=http://crs.rasdaman.com/def/crs/OGC/0/AnsiDate&2=http://crs.rasdaman.com/def/crs/EPSG/0/4326' > chla_time_instants <- chla_dims[[1]]$coefficients > cov_data <- chla$getCoverage( + bbox = OWSUtils$toBBOX(-10, -9, 40, 42), + time = chla_dims[[1]]$coefficients[[1]] + ) [ows4R][INFO] WCSCoverageSummary - Fetching Coverage envelope dimensions by CRS interpretation Unknown IO errorfailed to load external entity "http://crs.rasdaman.com/def/crs-compound?1=http://crs.rasdaman.com/def/crs/OGC/0/AnsiDate&2=http://crs.rasdaman.com/def/crs/EPSG/0/4326" Error : 1: Unknown IO error2: failed to load external entity "http://crs.rasdaman.com/def/crs-compound?1=http://crs.rasdaman.com/def/crs/OGC/0/AnsiDate&2=http://crs.rasdaman.com/def/crs/EPSG/0/4326" [ows4R][ERROR] WCSCoverageSummary - Error during CRS interpretation for srsName = 'http://crs.rasdaman.com/def/crs-compound?1=http://crs.rasdaman.com/def/crs/OGC/0/AnsiDate&2=http://crs.rasdaman.com/def/crs/EPSG/0/4326' ....\|-- lowerCorner: "2002-07-01T00:00:00.000Z" 40 -10 ....\|-- upperCorner: "2015-05-01T00:00:00.000Z" 42 -9[ows4R][INFO] WCSCoverageSummary - Fetching Coverage envelope dimensions by CRS interpretation Unknown IO errorfailed to load external entity "http://crs.rasdaman.com/def/crs-compound?1=http://crs.rasdaman.com/def/crs/OGC/0/AnsiDate&2=http://crs.rasdaman.com/def/crs/EPSG/0/4326" Error : 1: Unknown IO error2: failed to load external entity "http://crs.rasdaman.com/def/crs-compound?1=http://crs.rasdaman.com/def/crs/OGC/0/AnsiDate&2=http://crs.rasdaman.com/def/crs/EPSG/0/4326" [ows4R][ERROR] WCSCoverageSummary - Error during CRS interpretation for srsName = 'http://crs.rasdaman.com/def/crs-compound?1=http://crs.rasdaman.com/def/crs/OGC/0/AnsiDate&2=http://crs.rasdaman.com/def/crs/EPSG/0/4326' [ows4R][INFO] WCSGetCoverage - Fetching https://ows.rasdaman.org/rasdaman/ows?service=WCS&version=2.1.0&coverageId=AverageChloroColorScaled&subset=ansi(2002-07-01T00:00:00.000Z,2015-05-01T00:00:00.000Z)&subset=Lat(40,42)&subset=Lon(-10,-9)&format=image/tiff&request=GetCoverage \|=============================================================================================================\| 100% [ows4R][ERROR] WCSGetCoverage - Error while executing request 'GetCoverage' Warning: `/tmp/Rtmp3MwsDg/AverageChloroColorScaled_40,-10,42,-9.tif' not recognized as a supported file format. (GDAL error 4)Error: [rast] cannot open this file as a SpatRaster: /tmp/Rtmp3MwsDg/AverageChloroColorScaled_40,-10,42,-9.tif

[eblondel]

Thanks i will check. They mave have changed something in the Rasdaman test service I used for the Vignette.

[eblondel]

Something goes wrong in Rasdaman test server that is used in the examples. I've contacted their team.

[ecor]

Thank you and compliments for your package.

[falkmielke]

Hello!
I stumbled upon this issue when using ows4R with a new version of one of our local service API's, and thought the findings might be relevant to you and others.
The issue is that this specific API switched from returning geoTIFFs directly in version 1.0.0 to packing them in an mht container for version 2.0.1 (see here).

This is the API: https://geo.api.vlaanderen.be/DHMV/wcs?request=GetCapabilities
This affects queries with version=2.0.1 && format=image/tiff (yes, you get MHT despite asking for a tiff!)

When querying the latest version, ows4R received a file, as does the direct query, yet on my OS and browser the file had no extension.
I also receive a couple of error messages and warnings:
- Start tag expected, '<' not found
- cannot open this file as SpatRaster:…
- The raw file is not recognized as being in a supported file format. (GDAL error 4)

In fact, neither GDAL, nor terra/sf/python::rasterio, nor qgis were able to handle the file. When connecting qgis to the web service, it falls back to version 1.0.0.

The tif is contained within that MHT, and my colleague @hansvancalster figured out here how to extract it.

Here a working example:

require("httr")
require("stringr")
require("readr")
require("assertthat")


base_url = "https://geo.api.vlaanderen.be"
endpoint = "/DHMV/wcs"
url <- parse_url("https://geo.api.vlaanderen.be/DHMV/wcs")

# the query parameters which worked in QGIS
url$query <- list(
  SERVICE = "WCS",
  VERSION = "2.0.1",
  REQUEST = "GetCoverage",
  FORMAT = "image/tiff",
  COVERAGEID = "DHMVII_DTM_1m",
  SUBSET = "x,http://www.opengis.net/def/crs/EPSG/0/EPSG:31370(148000,149000)",
  SUBSET = "y,http://www.opengis.net/def/crs/EPSG/0/EPSG:31370(208000,209000)",
  SCALEFACTOR = "1",
  CRS = "EPSG:31370",
  RESPONSE_CRS = "EPSG:31370"
)

request <- build_url(url)


# get wcs data
mht_file <- tempfile(fileext = ".mht")

print(request)
print(mht_file)

response <- GET(url = request,
          write_disk(mht_file))

unpack_mht <- function(mht_filepath) {
  lines_raw <- read_lines_raw(mht_filepath)
  lines_char <- suppressWarnings(read_lines(mht_filepath))
  raw_vector <- read_file_raw(mht_filepath)

  #assert_that(any(str_detect(lines_char, "image/tiff")))
  start <- which(str_detect(lines_char, "^II\\*"))
  end <- length(lines_raw) - 1
  pos_start <- length(unlist(lines_raw[1:(start - 1)])) + start
  pos_end <- length(raw_vector) - (length(lines_raw[end + 1]) + 1)

  tif <- raw_vector[pos_start:pos_end]
  tif_path <- str_replace(mht_filepath, "mht", "tif")
  write_file(
    tif,
    tif_path
  )
  return(tif_path)
}

tif_file <- unpack_mht(mht_file)

require("terra")
raster <- rast(tif_file)
plot(raster, col = gray.colors(256))

Cheers,

Falk