Re: [geomesa-dev] FS - SFT - ORC does not support `GeometryCollection` a

[Weidong Duan <misslzyan108@xxxxxxxxx>]

I’m sorry , to implement the ‘GeometryCollection’ with four-dimension lists of doubles . And the pre email is the implement of `Geometry`

在 2019年4月2日，下午10:42，Weidong Duan <misslzyan108@xxxxxxxxx> 写道：

I know the `MultiPolygon`  is implemented by lists of lists of lists of double values, To implement the `GeometryCollection`, I use one column to store the types of  Point,LineString,Polygon,MultiPoint,MultiLineString,MultiPolygon,and with the another six tuple to store the real  data.

e.g.

Type,  point_x,point_y, linestring_x,linestring_y,polygon_x,polygon_y,multipoint_x,multipoint_y,multiLinestring_x,multilinestirng_y,multipolygon_x,multipolygon_y

Is this OK? With the extra columns to make the  ` ORC is a structured data format`

Thanks for your reply,

Weidong

在 2019年4月2日，下午10:06，Emilio Lahr-Vivaz <elahrvivaz@xxxxxxxx> 写道：

Hello,

The main reason is that ORC is a structured data format. We can model points as two double columns (one for x, one for y), line strings as two lists of double values, polygons as lists of lists of double values, etc. However, geometry and geometry collection can contain arbitrary geometry classes, so they don't have a consistent model. We could do something like store the geometry as a single column of WKT text or WKB bytes, but then you would lose a lot of the benefits of using a structured file format in the first place (efficient columnar compression, dictionary encoding, push down predicates, etc). However, if you wanted to implement them anyway, you would need to add appropriate readers and writers here: https://github.com/locationtech/geomesa/tree/master/geomesa-fs/geomesa-fs-storage/geomesa-fs-storage-orc/src/main/scala/org/locationtech/geomesa/fs/storage/orc/utils

Thanks,

Emilio

On 4/2/19 9:54 AM, Weidong Duan wrote:

Dear All , 

               Geomesa-FS-ORC  does not  support `GeometryCollection` and `Geometry` types.   Could you analyze  the consideration  about the two types not supported ? And  If I want to add the two types ,  Do you have some suggestions ?

Cheers,

Weidong

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