Hi
WCS has the ability to return a coverage as a GeoTiff file. Then if you want to display or process row data from this file in a Javascript web client, you need to have to ability to decode the “GeoTiff” part of this file.
I found a Tiff.js library compiled with Emscripten. I succeed to display a GeoTiff with this library as a Tiff file. But I still need to decode the GeoTiff tag and create the “PCSToImage” / “ImageToPCS” functions.
Two solutions :
compile GeoTiff with emscripten or rewrite some part of the GeoTiff function in javascript.
Another solution should be to ask the server to return the parameter from the image. Is there a way to do this without sending the full image to the server ?
Best regards
xavier lhomme
Hi Xavier,
there is a couple of options with WCS 2.
- you can request another format which is easier to handle by the client, such as PNG (builtin browser support).
- you can send a separate DescibeCoverage request and get an XML structure containing all metadata.
- you can direct the server (if it supports this - data formats are at its discretion) to deliver a multipart MIME document (same mechanism as email + attachment). Its first part will be the coverage description in XML, the second part the (TIFF or PNG or ...) image.To this end, use this request syntax (presented in GET/KVP and TIFF, for POST/XML see the protocol binding specs):
http://…/wcs?REQUEST=GetCoverage & ... &
FORMAT=image/tiff & MEDIATYPE=multipart/related
HTH,
Peter
On 10/03/2014 09:48 AM, xavier lhomme wrote:
Hi
WCS has the ability to return a coverage as a GeoTiff file. Then if you want to display or process row data from this file in a Javascript web client, you need to have to ability to decode the "GeoTiff" part of this file.
I found a Tiff.js library compiled with Emscripten. I succeed to display a GeoTiff with this library as a Tiff file. But I still need to decode the GeoTiff tag and create the "PCSToImage" / "ImageToPCS" functions.
Two solutions :
compile GeoTiff with emscripten or rewrite some part of the GeoTiff function in javascript.
Another solution should be to ask the server to return the parameter from the image. Is there a way to do this without sending the full image to the server ?
Best regards
xavier lhomme
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