Tim,
Ahh you hit the nail on the head. If these sitemaps contain just the indexing fields for records (and there is potentially more information available from another source) then there needs to be an unambiguous mechanism to link the things in the sitemaps to the things available via another means. i.e. GUIDs (could be URIs of various flavours including LSIDs).
LSID Authority plus sitemap would be good.
So we must mandate the use of GUIDs - your beer is practically safe.
Roger
On 14 May 2008, at 12:12, Tim Robertson wrote:
Hi Roger,
<Homer style>Hmmm free beer. Hang on, if worrying about trying to transfer large data is not a good incentive for standardising a transfer mechanism, is free beer any better? ;o)
But seriously,
If the proposal was along the lines of a Tab file:
- LSID kingdom phylum class order basis_of_record....
And then supporting files (star schema) with:
- LSID latitude longitude ....
If the wrappers generated these kind of structures using the same configuration generated when a user installed it, would you feel happier? This is really what Markus and I are proposing, and we fully support all the GUID generation work and I for one am desperate for it, including the BCI "datasource" level GUIDs.
The analogy to sitemaps is quite simple - these index files do not provide the full detail - they provide the means to build an index based on DwC concepts, that would then facilitate the accession of the full detail record
- e.g. through LSID. The LSID/GUID part is the same as the sitemap
URI - no?
Tim
-----Original Message----- From: Roger Hyam (TDWG) [mailto:rogerhyam@mac.com] Sent: Wednesday, May 14, 2008 12:58 PM To: Tim Robertson Cc: 'Markus Döring'; 'Hiscom-L Mailing List ((E-mail))'; tdwg-tapir@lists.tdwg.org Subject: Re: [tdwg-tapir] Fwd: Tapir protocol - Harvest methods?[SEC=UNCLASSIFIED]
Hi Tim,
The thing about the sitemaps is that they describe resources with URIs they are not just a dump of an excel file.
I will buy you a beer in Oz if any proposal that is put forward mandates the use of GUIDs for primary keys in the CSV files (other than perhaps the additional files Markus was proposing of one to many relationships). I'd buy you several beers if you manage to get it accepted :)
All the best,
Roger
BTW: Another way to represent a graph of data (other than a series of linked csv files) would be to do it in RDF as Turtle then zipped. This does way with the need of a separate dictionary to describe what the columns mean, has to be UTF-8, can include data types etc ... A script to explode this back to tables probably wouldn't be too slow but this is probably just fantasy on my part.
On 14 May 2008, at 11:21, Tim Robertson wrote:
Roegr writes "I worry that we are working out how to move data about quickly"
That is exactly what this is for, but why is it a worry (other than the likes of GBIF who really are worrying about moving data around quickly since everyone is shouting about latency problems)?
It is a 166 times (3meg versus 500meg) more efficient transfer of a data source for those wishing to transfer the whole thing. It is still standards compliant for the document passed across (DwC + flat extension schemas), and by incorporating it's generation into tools like a TAPIR wrapper, would ensure this. The reality is, many of the very large datasets have to come to GBIF like this - the transfer protocols existing just do not perform.
Furthermore, think how much easier it would be for someone like Catalogue of Life or ITIS to put up a service that says "hey, you give me the URL to your Locally generated DwC Index File and I'll give you back a report containing YOUR occurrence GUID, and MY LSID for your identification". Isn't that a good thing?
In my view these files are additional to any existing interfaces, only meet certain data type requirements and by no means detract from any of the important work (both technical and social aspects) on GUID assigning, document schemas etc. Therefore, like sitemaps became a requirement for large web sites, I think a more efficient standards based (than just dump your data and we'll handle it) approach is required for our community.
-----Original Message----- From: tdwg-tapir-bounces@lists.tdwg.org [mailto:tdwg-tapir-bounces@lists.tdwg.org] On Behalf Of Roger Hyam (TDWG) Sent: Wednesday, May 14, 2008 11:57 AM To: Markus Döring Cc: Hiscom-L Mailing List ((E-mail)); tdwg-tapir@lists.tdwg.org Subject: Re: [tdwg-tapir] Fwd: Tapir protocol - Harvest methods?[SEC=UNCLASSIFIED]
Generally if we are going to have csv files for data transfer we don't need to have software implementations just some documentation on what the csv files should contain. Something along the lines of:
- Make a report from your database as a csv file(s) with the
following columns... 2) Zip it up. 3) Either put it on a webserver and send us the URL or upload it using this webform.
We don't need to bother with TAPIR etc. You could even only produce a CSV file of the records that have changed so big data sets needn't be a problem.
I worry that we are working out how to move data about quickly and forgetting that the real goal is to integrate data and that will only come if people have GUIDs on the stuff they own and use other peoples GUIDs in their data. Solutions based around CSV files do nothing to move people in that direction and I would suspect lead to making matters worse.
Finding ourselves in hole digging quicker may not be the best option.
Roger
Roger Hyam Roger@BiodiversityCollectionsIndex.org http://www.BiodiversityCollectionsIndex.org
Royal Botanic Garden Edinburgh 20A Inverleith Row, Edinburgh, EH3 5LR, UK Tel: +44 131 552 7171 ext 3015 Fax: +44 131 248 2901 http://www.rbge.org.uk/
On 14 May 2008, at 10:21, Markus Döring wrote:
Interesting that we all come to the same conclusions... The trouble I had with just a simple flat csv file is repeating properties like multiple image urls. ABCD clients dont use ABCD just because its complex, but because they want to transport this relational data. We were considering 2 solutions to extending this csv approach. The first would be to have a single large denormalised csv file with many rows for the same record. It would require knowledge about the related entities though and could grow in size rapidly. The second idea which we think to adopt is allowing a single level of 1- many related entities. It is basically a "star" design with the core dwc table in the center and any number of extension tables around it. Each "table" aka csv file will have the record id as the first column, so the files can be related easily and it only needs a single identifier per record and not for the extension entities. This would give a lot of flexibility while keeping things pretty simple to deal with. It would even satisfy the ABCD needs as I havent yet seen anyone requiring 2 levels of related tables (other than lookup tables). Those extensions could even be a simple 1-1 relation, but would keep things semantically together just like a xml namespace. The darwin core extensions would be good for example.
So we could have a gzipped set of files, maybe with a simple metafile indicating the semantics of the columns for each file. An example could look like this:
# darwincore.csv 102 Aster alpinus subsp. parviceps ... 103 Polygala vulgaris ...
# curatorial.csv 102 Kew Herbarium 103 Reading Herbarium
# identification.csv 102 2003-05-04 Karl Marx Aster alpinus L. 102 2007-01-11 Mark Twain Aster korshinskyi Tamamsch. 102 2007-09-13 Roger Hyam Aster alpinus subsp. parviceps Novopokr. 103 2001-02-21 Steve Bekow Polygala vulgaris L.
I know this looks old fashioned, but it is just so simple and gives us so much flexibility. Markus
On 14 May, 2008, at 24:39, Greg Whitbread wrote:
We have used a very similar protocol to assemble the latest AVH cache. It should be noted that this is an as-well-as protocol that only works because we have an established semantic standard (hispid/ abcd).
greg
trobertson@gbif.org wrote:
Hi All,
This is very interesting too me, as I came up with the same conclusion while harvesting for GBIF.
As a "harvester of all records" it is best described with an example:
- Complete Inventory of ScientificNames: 7 minutes @ the limited
200 records per page
- Complete Harvesting of records:
- 260,000 records
- 9 hours harvesting duration
- 500MB TAPIR+DwC XML returned (DwC 1.4 with geospatial and
curatorial extensions)
- Extraction of DwC records from harvested XML: <2 minutes
- Resulting file size 32MB, Gzipped to <3MB
I spun hard drives for 9 hours, and took up bandwidth that is paid for, to retrieve something that could have been generated provider side in minutes and transferred in seconds (3MB).
I sent a proposal to TDWG last year termed "datamaps" which was effectively what you are describing, and I based it on the Sitemaps protocol, but I got nowhere with it. With Markus, we are making more progress and I have spoken with several GBIF data providers about a proposed new standard for full dataset harvesting and it has been received well. So Markus and I have started a new proposal and have a working name of 'Localised DwC Index' file generation (it is an index if you have more than DwC data, and DwC is still standards compliant) which is really a GZipped Tab file dump of the data, which is slightly extensible. The document is not ready to circulate yet but the benefits section reads currently:
- Provider database load reduced, allowing it to serve real
distributed queries rather than "full datasource" harvesters
- Providers can choose to publish their index as it suits them,
giving control back to the provider
- Localised index generation can be built into tools not yet
capable of integrating with TDWG protocol networks such as GBIF
- Harvesters receive a full dataset view in one request, making it
very easy to determine what records are eligible for deletion
- It becomes very simple to write clients that consume entire
datasets. E.g. data cleansing tools that the provider can run:
- Give me ISO Country Codes for my dataset
- The application pulls down the providers index file, generates
ISO country code, returns a simple table using the providers own identifier
- Check my names for spelling mistakes
- Application skims over the records and provides a list that are
not known to the application
- Providers such as UK NBN cannot serve 20 million records to the
GBIF index using the existing protocols efficiently.
- They have the ability to generate a localised index however
- Harvesters can very quickly build up searchable indexes and it
is easy to create large indices.
- Node Portal can easily aggregate index data files
- true index to data, not an illusion of a cache. More like Google
sitemaps
It is the ease at which one can offer tools to data providers that really interests me. The technical threshold required to produce services that offer reporting tools on peoples data is really very low with this mechanism. This and the fact that large datasets will be harvestable - we have even considered the likes of bit-torrent for the large ones although I think this is overkill.
As a consumer therefore I fully support this move as a valuable addition to the wrapper tools.
Cheers
Tim (wrote the GBIF harvesting, and new to this list)
Begin forwarded message:
> From: "Aaron D. Steele" eightysteele@gmail.com > Date: 13 de mayo de 2008 22:40:09 GMT+02:00 > To: tdwg-tapir@lists.tdwg.org > Cc: Aaron Steele asteele@berkeley.edu > Subject: Re: [tdwg-tapir] Tapir protocol - Harvest methods? > > at berkeley we've recently prototyped a simple php program that > uses an existing tapirlink installation to periodically dump > tapir resources into a csv file. the solution is totally generic > and can dump darwin core (and technically abcd schema, although > it's currently untested). the resulting csv files are zip > archived and made accessible using a web service. it's a simple > approach that has proven to be, at least internally, quite > reliable and useful. > > for example, several of our caching applications use the web > service to harvest csv data from tapirlink resources using the > following > process: > 1) download latest csv dump for a resource using the web > service. > 2) flush all locally cached records for the resource. > 3) bulk load the latest csv data into the cache. > > in this way, cached data are always synchronized with the > resource and there's no need to track new, deleted, or changed > records. as an aside, each time these cached data are queried by > the caching application or selected in the user interface, > log-only search requests are sent back to the resource. > > after discussion with renato giovanni and john wieczorek, we've > decided that merging this functionality into the tapirlink > codebase would benefit the broader community. csv generation > support would be declared through capabilities. although > incremental harvesting wouldn't be immediately implemented, we > could certainly extend the service to include it later. > > i'd like to pause here to gauge the consensus, thoughts, > concerns, and ideas of others. anyone? > > thanks, > aaron > > 2008/5/5 Kevin Richards RichardsK@landcareresearch.co.nz: >> >> I think I agree here. >> >> The harvesting "procedure" is really defined outside the Tapir >> protocol, is it not? So it is really an agreement between the >> harvester and the harvestees. >> >> So what is really needed here is the standard procedure for >> maintaining a "harvestable" dataset and the standard procedure >> for harvesting that dataset. >> We have a general rule at Landcare, that we never delete >> records >> in our datasets - they are either deprecated in favour of >> another record, and so the resolution of that record would >> point >> to the new record, or the are set to a state of "deleted", but >> are still kept in the dataset, and can be resolved (which would >> indicate a state of deleted). >> >> Kevin >> >> >>>>> "Renato De Giovanni" renato@cria.org.br 6/05/2008 7:33 >>>>> a.m. >>>>>>>> >> >> Hi Markus, >> >> I would suggest creating new concepts for incremental >> harvesting, either in the data standards themselves or in some >> new extension. >> In the case of TAPIR, GBIF could easily check the mapped >> concepts before deciding between incremental or full >> harvesting. >> >> Actually it could be just one new concept such as >> "recordStatus" >> or >> "deletionFlag". Or perhaps you could also want to create your >> own definition for dateLastModified indicating which set of >> concepts should be considered to see if something has changed >> or >> not, but I guess this level of granularity would be difficult >> to >> be supported. >> >> Regards, >> -- >> Renato >> >> On 5 May 2008 at 11:24, Markus Döring wrote: >> >>> Phil, >>> incremental harvesting is not implemented on the GBIF side as >>> far as I am aware. And I dont think that will be a simple >>> thing >>> to implement on the current system. Also, even if we can >>> detect >>> only the changed records since the last harevesting via >>> dateLastModified we still have no information about deletions. >>> We could have an arrangement saying that you keep deleted >>> records as empty records with just the ID and nothing else (I >>> vaguely remember LSIDs were supposed to work like this too). >>> But >>> that also needs to be supported on your side then, never >>> entirely removing any record. I will have a discussion with >>> the >>> others at GBIF about that. >>> >>> Markus >> _______________________________________________ >> tdwg-tapir mailing list >> tdwg-tapir@lists.tdwg.org >> http://lists.tdwg.org/mailman/listinfo/tdwg-tapir >> >> >> >> >> Please consider the environment before printing this email >> >> WARNING : This email and any attachments may be confidential >> and/ or privileged. They are intended for the addressee only >> and >> are not to be read, used, copied or disseminated by anyone >> receiving them in error. >> If >> you are >> not the intended recipient, please notify the sender by return >> email and delete this message and any attachments. >> >> The views expressed in this email are those of the sender and >> do >> not necessarily reflect the official views of Landcare >> Research. >> http:// www.landcareresearch.co.nz >> _______________________________________________ >> tdwg-tapir mailing list >> tdwg-tapir@lists.tdwg.org >> http://lists.tdwg.org/mailman/listinfo/tdwg-tapir >> >> > _______________________________________________ > tdwg-tapir mailing list > tdwg-tapir@lists.tdwg.org > http://lists.tdwg.org/mailman/listinfo/tdwg-tapir
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