Hello Julian,
I believe the geospatial support you are talking about is based on
SQL/MM right ?
For now I am just exploring Calcite (a few minutes each time when builds
are running), to see if we can use it's SQL parser and interpretor as an
alternative to OGC Filter/Expression queries.
Collaboration would be nice, we should start by using the same geometry
objets and library, if calcite has it's own that will be a problem.
The choice is limited :
- JTS : https://github.com/locationtech/jts
- Esri Geometry : https://github.com/Esri/geometry-api-java
Do you know any other ?
So far in SIS we didn't choose any library yet because both are limited
to two (and a half) dimensions and their API are completely locked, we
can't add new geometry types or operations. This is going to be a real
problem since we require 3D geometries more and more.
A idea would be to start a new project at Apache for N dimension
geometries but that won't be me, I don't have the time nor the math
skills to do it.
Thanks for the links
Johann
On 20/03/2018 18:05, Julian Hyde wrote:
Johann,
It’s great to meet someone from the SIS project.
As you may know, we have been adding GeoSpatial support for Calcite for a while
now[1][2][3][4]. We have a GEOMETRY data type and have implemented a
significant fraction of the OpenGIS SQL function set. The goal is to make
things work row-at-a-time to start with, but incrementally recognize particular
patterns that can be written to use particular “spatial indexes”.
I use the term “spatial index” very loosely. It doesn’t have to be an index or
any particular format. We aim to expose whatever data structures the underling
engine supports - and even make accelerated spatial queries possible on engines
without dedicated spatial structures - HBase-style key-sorted tables for
example.
So, please let us know how we can help with SIS, or if you would like to help
us build out our Geospatial support.
It looks like your specific questions about adapters are being answered
elsethread.
Julian
[1] https://issues.apache.org/jira/browse/CALCITE-1968
<https://issues.apache.org/jira/browse/CALCITE-1968>
[2] https://issues.apache.org/jira/browse/CALCITE-2031
<https://issues.apache.org/jira/browse/CALCITE-2031>
[3] https://issues.apache.org/jira/browse/CALCITE-1861
<https://issues.apache.org/jira/browse/CALCITE-1861>
[4] https://issues.apache.org/jira/browse/CALCITE-2160
<https://issues.apache.org/jira/browse/CALCITE-2160>
On Mar 20, 2018, at 4:33 AM, johann sorel <[email protected]> wrote:
Hello,
A quick presentation since I am new here :
My name is Johann Sorel, I am developer (and PMC) on Apache SIS
(http://sis.apache.org), and on some others GeotoolKit, Examind, GeoAPI,
...etc...
I work mostly on data models and decoder/encoders.
I have a few questions on Adaptors to use the SQL capabilities of Calcite in
Apache SIS.
- Where can we find a up-to-date tutorial or example to execute a basic SELECT
query in Java.
the short code at
https://calcite.apache.org/docs/howto.html#implementing-an-adapter is obsolete
with version 1.16.
and do not show how we loop on the result records.
- The above code use CalcitePrepareImpl which doc says it's for testing purpose
and unstable, is there a stable api somewhere ?
I'm sorry if those are newbie questions but I could not find the answers in the
doc.
Thanks
Johann Sorel
