One big problem we have is that forLocation is not really pointing to one or
even two (lat + long) fields in Lucene. It's pointing to a user property that
leads to a set of Lucene fields (one per grid level + lat + long. That's why we
have shied away from naming it Field.
I guess LatLong is the most precise name but it's a rather nasty contraction
which is something we try and avoid as much as we can historically.
On 21 déc. 2011, at 15:30, Karel Maesen wrote:
> Hi Emmanuel,
>
> My preference:
>
> .forLocation("location")
> .forLatitudeField("lat").forLongitudeField("long")
>
> Btw, I quite like "LatLong" as an alternative for the term "Coordinates" or
> "Location". It makes clear what the meaning is of the coordinates/location
> interface/method, and conditions the reader as to the order of latitude and
> longitude. It is also used in the Google Maps JS API (well almost, the use
> the imo uglier "LatLng").
>
> Regards,
>
> Karel
>
> On 21 Dec 2011, at 14:59, Emmanuel Bernard wrote:
>
>> Which one do you prefer (line in bold for each sample)?
>>
>> builder
>> .spatial()
>> .onCoordinates( "location" ) or
>> .forCoordinates("location") or .forLocation("location") or something else
>> .within( 500, Unit.KM )
>>
>> .of().latitude(48.858333d).longitude(2.294444d)
>> .createQuery();
>>
>>
>>
>> builder
>> .spatial()
>> .onLatitudeField( "latitude"
>> ).onLongitudeField( "longitude" ) or .forLatitudeField( "latitude"
>> ).forLongitudeField( "longitude" ) or something else
>> .within( 51, Unit.KM )
>> .of().latitude( 24d
>> ).longitude( 31.5d )
>> .createQuery();
>>
>> On 5 déc. 2011, at 16:21, Emmanuel Bernard wrote:
>>
>>> Nicolas and I have made good progress on Geospatial queries for Hibernate
>>> Search.
>>>
>>> # Geospatial indexing and queries
>>>
>>> Our goal is to give a reasonable but pragmatic answer to geoloc queries. We
>>> do not try and implement the most obscure geo-projection favored by ancient
>>> greeks, we do not try and find matching elements within a triangular-shaped
>>> donut on Mars' surface etc. We have purposely limited the current
>>> implementation to:
>>>
>>> - find matching elements in a circle (we have plans to extends to matching
>>> elements in a rectangle if popular demands arise but in our opinion this
>>> will not be useful or rather be misleading)
>>> - use the internationally accepted geo projection as it is i18n neutral and
>>> not centered on one particular country. We can plan on opening to other
>>> projections if the need arise (esp if data points are provided in different
>>> projections).
>>>
>>> We made sure to expose as few gory details as possible.
>>>
>>> That being said, here are more information and questions.
>>>
>>> The JIRA is https://hibernate.onjira.com/browse/HSEARCH-923
>>> The branch is
>>> https://github.com/emmanuelbernard/hibernate-search/tree/HSEARCH-923
>>>
>>> ## How is geoloc data exposed to the domain model?
>>>
>>> We plan on supporting three approaches:
>>>
>>> ### Special interface and embeddable object
>>>
>>> Using a specific interface as the property return type:
>>> `o.h.s.spatial.Coordinates`
>>>
>>> @Indexed
>>> public class Address {
>>> @Field String city;
>>> @Spatial Coordinates location = new Coordinates() {
>>> public double getLatitude() { ... }
>>> public double getLongitude() { ... }
>>> }
>>> }
>>>
>>> ### Special interface implemented by the entity
>>>
>>> Using a specific interface implemented by the entity:
>>> `o.h.s.spatial.Coordinates`
>>>
>>> @Indexed @Spatial
>>> public class Address {
>>> @Field String city;
>>>
>>> public double getLatitude() { ... }
>>> public double getLongitude() { ... }
>>> }
>>>
>>> ### Use JTS's Point type
>>>
>>> Use `Point` as the spatial property type.
>>>
>>> ### (maybe) `double` hosted by two unrelated properties
>>>
>>> The problem is to find a nice way to bind these properties to the spatial
>>> data.
>>>
>>> ## How is geoloc data indexed
>>>
>>> There will be two strategies
>>>
>>> - index latitude and longitude as is and do a AND query matching both. This
>>> typically works nicely for small datasets.
>>> - index latitude and longitude as matching a 15 level grid (from most
>>> generic to most specific). this typically works nicely for big datasets
>>>
>>> ## Query DSL
>>>
>>> We have worked to make a fluent spatial API to the current query DSL.
>>> Before we go on implementing it, we would like your feedback. Some points
>>> remains open.
>>>
>>> ### General overview
>>>
>>> builder.spatial()
>>> .scoreByProximity() //not implemented yet
>>> .onField("coord")
>>> .boostedTo(2)
>>> .within(2).km()
>>> .of( coordinates )
>>> .createQuery();
>>>
>>> ### onField
>>>
>>> onField is not a good name. It has a slightly meaning than when it's used
>>> in range().onField(). We need to find a better name:
>>>
>>> - onField
>>> - onGrid
>>> - onCoordinates
>>> - onLocation
>>>
>>> This really represents the metadata set where the location will be stored.
>>> In the boolean approach, we store latitude and longitude. In the grid
>>> approach, we store latitude,
>>> longitude and the set of grids coordinates belong to.
>>>
>>> .onField() does accept a field name which can be the `Coordinates` property
>>> or the virtual field used by the class-level bridge (if lat and long are
>>> top level properties).
>>>
>>> When latitude and longitude are independent properties, we would use
>>>
>>> builder.
>>> .onLatitudeField("lat")
>>> .andLongitudeField("lat")
>>>
>>> ### Surface checked
>>>
>>> #### Option 1: centeredOn
>>>
>>> .centeredOn(double, double)
>>> //or
>>> .centeredOn()
>>> .latitude(double)
>>> .longitude(double)
>>> //or
>>> .centeredOn(SpatialIndexable)
>>> .centeredOn(JTS.Point) // hard dependency on JTS even for non spatial
>>> users :(
>>> .centeredOn(Object) //? to avoid JTS dep
>>>
>>> - Should we have a version accepting Object?
>>> - What is best, centeredOn(double, double) or
>>> centeredOn().latitude(double).longitude(double)?
>>>
>>> #### Option 2: in / within
>>>
>>>
>>> //query within circle
>>> b.spatial()
>>> .onField("coord")
>>> .within(2).km()
>>> .of(SpatialIndexable)
>>>
>>> .within(2).km()
>>> .of()
>>> .latitude()
>>> .longitude()
>>> .createQuery()
>>>
>>> //or with a different unit handling
>>>
>>> //query within circle
>>> b.spatial()
>>> .onField("coord")
>>> .within(2, Unit.km)
>>> .of(SpatialIndexable)
>>>
>>> .within(2, Unit.km)
>>> .of()
>>> .latitude()
>>> .longitude()
>>> .createQuery()
>>>
>>> My reason to support units is that a. it's explicit and b. when those
>>> geosuckers improve, we could support time units like mins or hours. Note,
>>> that's a very hard problem to crack and solutions are resource intensive
>>> and not very accurate. None really do it correctly, not Google for sure.
>>>
>>>
>>> We could support rectangles / boxes if really needed
>>>
>>> //query in box
>>> b.spatial()
>>> .onField("coord")
>>> .inBox()
>>> .from()
>>> .to()
>>> .createQuery();
>>>
>>> //more formal but more correct wrt projection
>>> b.spatial()
>>> .onField("coord")
>>> .inBox()
>>> .withUpperLeft()
>>> .withLowerRight()
>>> .createQuery();
>>>
>>>
>>> Please give us your feedback.
>>>
>>> ## TODOs
>>>
>>> - Implement fluent DSL
>>> - Implement Special interface implemented by the entity
>>> - Implement Use JTS's Point type
>>> - Implement bridge that supports indexing for boolean queries based on lat
>>> and long instead of the grid.
>>> - Implement @Spatial as a marker annotation for the spatial bridge
>>> - Implement variable score based on proximity
>>> Today we use constant score, ie in = 1, out = 0. We can think about a score
>>> that goes from 1 to 0 based on the distance from the center to the circle
>>> size
>>> We can imagine queries that should return close elements above far elements.
>>> Note we might need a score going from 1 to .5 or some other value. Need to
>>> think about that.
>>> - Write how to focused doc
>>> - Write doc on perf comparing grid vs boolean queries
>>> - Convert to JBoss logging
>>> - Add unit test using faceting + spatial queries
>>>
>>> Emmanuel
>>> _______________________________________________
>>> hibernate-dev mailing list
>>> hibernate-dev@lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>>
>> _______________________________________________
>> hibernate-dev mailing list
>> hibernate-dev@lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>
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