Changes between Initial Version and Version 1 of HowToGetBrowseImg

Timestamp:

11/01/05 08:54:38 (19 years ago)

Author:

joe

Comment:

--

HowToGetBrowseImg

@@ +1 @@
+= How can I get the browse images (jpeg, png, gif, etc) for observations? =
+
+== WARNING: Prototype ==
+
+The current implementation is much more obfuscated than it should be, as it is a prototype, and is not consistently implemented
+between data providers.
+
+The 'browse products' are served as metadata attached to VSO records -- the VSO message format allows User Interfaces
+to add extra elements to the request, which the VSO will pass on to the Data Provider that seem to be able to handle the
+request based on the elements that the VSO knows about.  The Data Providers can then vary their behaviour based on the
+new parameters.
+
+We ask those Data Providers who wish to do this to either prefix the element with their provider id, or to ContactUs, so that
+we can make sure two different Data Providers don't use the same name for different features.
+
+The only element currently in use is 'field', which is passed an array of strings, requesting extra fields to return with the
+metadata.  If the array contains an item named 'thumbnail', it will return one of the following with the rest of the returned record.
+
+ 1. Absolutely nothing.  Not all data providers have browse images to return, and even if they do, they may not have complete coverage.
+ 1. A complex type 'extra', with an element 'thumbnail'.  Please note that this is ''not'' part of the formal VSO API, and it might change as this is a prototype.
+
+The return structure looks like one of the three following, when deserialized using Perl's SOAP::Lite:
+
+{{{
+extra => {
+    thumbnail => 'url_string'
+}
+extra => {
+    thumbnail => {
+        lowres => 'url_string',
+        hires  => 'url_string',
+    }
+}
+
+extra => {
+    thumbnail => {
+        lowres => {
+            loc => 'url_string',
+            w   => 'width_in_pixels',
+            h   => 'height_in_pixels',
+        },
+        hires => {
+            loc => 'url_string',
+            w   => 'width_in_pixels',
+            h   => 'height_in_pixels',
+        },
+    }
+}
+}}}
+
+The first format is deprecated, and to the best of my knowledge, is no longer in use.
+
+Both 'lowres' and 'hires' are optional -- It is
+possible that they data provider may only have one size of images.  If they're both not there,
+the data provider hopefully won't send the structure, but it is a possibility.
+
+The 'lowres' should be somewhere near 128x128, and the 'hires' ones are
+something larger, but it's up to the individual data providers.  If they use the last format,
+they will specify the size of the browse images in pixels.