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
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 ?
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