lucene-general mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Grant Ingersoll <gsing...@apache.org>
Subject Re: [spatial] Cartesian "Tiers" nomenclature
Date Tue, 29 Dec 2009 13:25:09 GMT

On Dec 29, 2009, at 6:28 AM, Michael McCandless wrote:

> It's great that there's such a sudden burst of energy to improve
> spatial in both Solr and Lucene!
> 
> Isn't this concept the same as "trie" (for Lucene's numeric fields),
> but in 2D not 1D?
> 
> If so, I think "tiles" doesn't convey that they recursively
> subdivide.
> 
> Also: why does this notion even need naming so badly?  Why does this
> concept "leak" out of the abstraction?  Shouldn't this (cartesian
> tier, cartesian tier plotter) all be "under the hood"?  I make a
> SpatialField, I index it, I can then make SpatialShapeQuery, a
> SpatialDistanceSort, etc.?

To some extent, but there are tradeoffs between the Lucene numerics and the tiles/tiers in
terms of performance, etc. such that one at least needs to understand some high level notion
of what the data structure is in order to make an informed choice about when to use it.

> 
> Ie, "trie" is known within Lucene, but doesn't leak out -- the outside
> world knows it as "Numeric*".  Trie is an implementation detail,
> inside Lucene.

Not entirely true, in Solr, it's called a Trie*Field (TrieDoubleField, TrieIntField, etc.)
as numeric is too generic since Solr has other numerics.

> 
> (NOTE: I only know just enough about spatial to be dangerous...)
> 
> Mike
> 
> On Tue, Dec 29, 2009 at 2:49 AM, patrick o'leary <pjaol@pjaol.com> wrote:
>> Ah the language of math is the ultimate lingua franca -
>> Nice !
>> 
>> When you look at the coordinates entity from KML, ask why are the lat /
>> longs reversed to long/ lat?
>> Answer because the folks working on the display thought in terms of *display
>> not GIS*, the point is over Y degrees of longitude and down X degrees of
>> latitude.
>> 
>> But again that's not a convention used outside a little part of GeoTools or
>> KML, GML / GeoRSS are again just the regular lat,long (NS,EW), or projected
>> EPSG or other standard projections in  OGC 05-011.
>> To my knowledge google are the only real pushers of (EW,NS) these days.
>> 
>> So what does this diatribe mean? We're kind of at the bleeding edge of
>> defining the standard, hence the difficulty of finding data on it.
>> This is one reason why locallucene and localsolr became popular, it solved a
>> problem simply.
>> 
>> Doc's about it exist on gissearch.com
>> dzone are doing articles on it
>> http://java.dzone.com/articles/spatial-search-hibernate?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+javalobby%2Ffrontpage+%28Javalobby+%2F+Java+Zone%29
>> 
>> Locallucene in google has over 8,000 results
>> http://www.google.com/search?q=locallucene
>> 
>> Localsolr has over 4,000 results
>> http://www.google.com/search?q=localsolr
>> 
>> I've seen and help with installations all over the place, heck even codehaus
>> use it, as do folks on github with geonames db.
>> I see named it mathematically & scientifically correct, and  gaining enough
>> traction and popularity to start becoming part of the standard, not just
>> duplicating one.
>> 
>> I can't honestly see how a refactoring is bringing anything positive to
>> this, when there isn't a good standard out there yet.
>> 
>> 
>> On Mon, Dec 28, 2009 at 10:22 PM, Mattmann, Chris A (388J) <
>> chris.a.mattmann@jpl.nasa.gov> wrote:
>> 
>>> Hi Patrick,
>>> 
>>> Interesting. It seems like there is a precedent already in the Local Lucene
>>> and Local SOLR packages that define "CartesianTier" as lingua franca.
>>> 
>>> Like I said in an earlier email it depends on who you talk to regarding the
>>> preference of what to call these Tiles/Grids/Tiers, etc., and that seems to
>>> be further evidenced by your research.
>>> 
>>> I for one donĀ¹t really have a preference but precedent matters to me and if
>>> Tiers have been used to date then there should be strong consideration to
>>> use that nomenclature and +1 from me.
>>> 
>>> Cheers,
>>> Chris
>>> 
>>> On 12/28/09 9:25 PM, "patrick o'leary" <pjaol@pjaol.com> wrote:
>>> 
>>>> So trying no to drag this out, the most frequent generic term used in GIS
>>>> software is SRID
>>>> http://en.wikipedia.org/wiki/SRID
>>>> 
>>>> Again this provides just a basic nomenclature for the high level element,
>>>> somewhat the blackbird of objects rather than the defining the magpie
>>> (sorry
>>>> for the CS 101 reference)
>>>> 
>>>> But it should show that every implementation is unique in some format.
>>>> Perhaps as unique as CartesianTier's ( sorry Ted ! )
>>>> 
>>>> 
>>>> 
>>>> On Mon, Dec 28, 2009 at 5:26 PM, patrick o'leary <pjaol@pjaol.com>
>>> wrote:
>>>> 
>>>>> Hmm, depends, tiles indicate to me a direct correlation between the id
>>> and
>>>>> a map tile, which will depend upon using the right projection
>>>>> with the cartesian plotter
>>>>> 
>>>>> 
>>>>> On Mon, Dec 28, 2009 at 2:56 PM, Grant Ingersoll <gsingers@apache.org
>>>> wrote:
>>>>> 
>>>>>> 
>>>>>> On Dec 28, 2009, at 4:19 PM, patrick o'leary wrote:
>>>>>> 
>>>>>>> Hmm, but when you say grid, to me that's just a bunch of regularly
>>>>>> spaced
>>>>>>> lines..
>>>>>> 
>>>>>> Yeah, I hear you.  I chose spatial tiles for the Solr patch, but
>>> spatial
>>>>>> grid would work too.  Or map tiles/map grids.  That anchors it into
the
>>>>>> spatial world, since we're calling Lucene's spatial contrib/spatial
and
>>>>>> Solr's Solr Spatial.
>>>>>> 
>>>>>>> 
>>>>>>> On Mon, Dec 28, 2009 at 1:16 PM, Grant Ingersoll <gsingers@apache.org
>>>>>>> wrote:
>>>>>>> 
>>>>>>>> 
>>>>>>>> On Dec 28, 2009, at 3:51 PM, patrick o'leary wrote:
>>>>>>>> 
>>>>>>>>> So Grant here's the deal behind the name.
>>>>>>>>> Cartesian because it's a simple x.y coordinate system
>>>>>>>>> Tier because there are multiple tiers, levels of resolution.
>>>>>>>>> 
>>>>>>>>> If you look at it closer:
>>>>>>>>> - To programmers there's a quadtree implementation
>>>>>>>>> - To web users who use maps these are grids / tiles.
>>>>>>>>> - To GIS experts this is a form of multi-resolution raster-ing.
>>>>>>>>> - To astrophysicists these are tiers.
>>>>>>>>> - To the MS folks I've talked to they have quad something
or other.
>>>>>>>>> - To math folks Cartesian levels makes sense.
>>>>>>>>> 
>>>>>>>>> Can't make all the people happy all the time,
>>>>>>>> 
>>>>>>>> Right, but as far as I can tell (and I've only done, say
an hour of
>>>>>>>> research), I can't find anyone who calls them Cartesian Tiers
other
>>>>>> than us.
>>>>>>>> 
>>>>>>>> Personally, I think web users are the largest group (after
all,
>>> aren't
>>>>>> we
>>>>>>>> all web users?) out there and therefore will be the most
familiar
>>> with
>>>>>>>> either grid or tile.  FWIW, I have tentatively called the
Solr
>>>>>> FieldType to
>>>>>>>> support this "SpatialTileField" as in it represents a tile
in the
>>>>>> spatial
>>>>>>>> sense.  I'd be fine with SpatialGridField as well (GridField
seems a
>>>>>> bit too
>>>>>>>> generic).
>>>>>> 
>>>>>> 
>>>>>> 
>>>>> 
>>>> 
>>> 
>>> 
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> Chris Mattmann, Ph.D.
>>> Senior Computer Scientist
>>> NASA Jet Propulsion Laboratory Pasadena, CA 91109 USA
>>> Office: 171-266B, Mailstop: 171-246
>>> Email: Chris.Mattmann@jpl.nasa.gov
>>> WWW:   http://sunset.usc.edu/~mattmann/<http://sunset.usc.edu/%7Emattmann/>
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> Adjunct Assistant Professor, Computer Science Department
>>> University of Southern California, Los Angeles, CA 90089 USA
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> 
>>> 
>>> 
>> 

--------------------------
Grant Ingersoll
http://www.lucidimagination.com/

Search the Lucene ecosystem using Solr/Lucene: http://www.lucidimagination.com/search


Mime
View raw message