Thanks Max, I’ve seen in Pharo 5 OrderedDictionary, OrderedPreservingDictionary and some others. I guess they have the same intent. I was actually trying them right now :) Cheers, Cédrik

Le 23 avr. 2016 à 13:57, Max Leske <maxleske@gmail.com> a écrit :

There was talk about an ordered dictionary implementation IIRC a couple of months ago on this list.

I’ve attached an implementation I found in a thread from 2010 (may not work out of the box).

Cheers, Max

<OrderedDictionary.st>

...

On 23 Apr 2016, at 13:46, Cédrick Béler <cdrick65@gmail.com> wrote:

A dictionary with keys being the timestamp or the spatiotemporal object would probably do it... I think I’ll do that but I wonder if there are better solutions out there ^^.

Cheers,

Cédrik

There are a lot of spatial access data structures: https://en.wikipedia.org/wiki/Spatial_database#Spatial_index <https://en.wikipedia.org/wiki/Spatial_database#Spatial_index>

But for a prototype I don't think you care; a simple linear search should be ok for testing

Yes sure but I keep that in mind for later « exploration ».

until you have thousands and thousands of records.

Potentially, on a person lifetime, adding hundreds information a day (and probably higher order of magnitude), I think we can easily reach millions of data quite easily :) 100 per day, in 10 years => 365 000 1000 per day in 100 years => 36 500 000 What I want is keeping track of all positions a person can have in his life (what can easily reach millions) and then rely on these « points » to index information added in the system.

It's probably more important to really explore what you need and how your constraints will influence the API

but I agree and I’ll work on that first.

(e.g. since we haven't invented teleportation yet, events for one person that are close in time are necessarily close in space)

yes… for now but in 50 years who knows :) This remark is nevertheless interesting as a premise that can be used to check the validity of data (geospatial resolver are not that precise). But yeah for now, an OrderedDic or another classic collection will do the job and will let me explore the API (and we might discuss it ^^). I start this discussion as I thing this is one central modeling concept of what I want to do. Cheers, Cédrik

On 23 April 2016 at 14:08, Cédrick Béler <cdrick65@gmail.com <mailto:cdrick65@gmail.com>> wrote: Thanks Max,

I’ve seen in Pharo 5 OrderedDictionary, OrderedPreservingDictionary and some others. I guess they have the same intent.

I was actually trying them right now :)

Cheers,

Cédrik

...

Le 23 avr. 2016 à 13:57, Max Leske <maxleske@gmail.com <mailto:maxleske@gmail.com>> a écrit :

There was talk about an ordered dictionary implementation IIRC a couple of months ago on this list.

I’ve attached an implementation I found in a thread from 2010 (may not work out of the box).

Cheers, Max

<OrderedDictionary.st>

...

On 23 Apr 2016, at 13:46, Cédrick Béler <cdrick65@gmail.com <mailto:cdrick65@gmail.com>> wrote:

A dictionary with keys being the timestamp or the spatiotemporal object would probably do it... I think I’ll do that but I wonder if there are better solutions out there ^^.

Cheers,

Cédrik

-- Damien Pollet type less, do more [ | ] http://people.untyped.org/damien.pollet <http://people.untyped.org/damien.pollet>

Sure, but 1) that's not a lot 2) do you even know if you need interactive stuff or if batch processing is ok?

interactive I would say… but hard to be certain right now as it depends on design choices… do we cache ? do we aggregate past data ? extra indexes ? I’ll see later. I want something simple, keep everything… and query according to time interval, areas (contexts)… But yes for now this is pointless to look for something optimal and I’ll use a dictionary as it will be small at start. Cheers, Cédrik

-- Damien Pollet type less, do more [ | ] http://people.untyped.org/damien.pollet <http://people.untyped.org/damien.pollet>

Hi Esteban, Thanks a lot, I think I’ll try your History package, it seems to be a very good starting point (instead of hacking it myself). I’ll try it soon. Thanks for all the information ;) Cheers, Cédrik

Le 23 avr. 2016 à 18:28, Esteban A. Maringolo <emaringolo@gmail.com> a écrit :

Maybe instead of having a Dictionary, you can use my History package [1]. It allows you to add elements to "the history", and the History class will provide certain "lookup" strategies depending on how you want to query it.

It is a trimmed down version of an utility class I used for years in commercial products where the History contained thousands of elements. This version uses linear search, my previous implementation used binary search which was significantly faster with lots of elements in the collection.

Of course it doesn't solve your spatial queries needs, I don't know if there is something in Smalltalk for that other than the distance between two coordinates[2], PostgreSQL 9.2 has some support for "temporal" data/tables which you could combine with PostGIS if you need to combine a spatial query with a temporal one [3].

Regards,

[1] http://www.smalltalkhub.com/#!/~emaringolo/History [2] http://pastebin.com/ThKDXCKK [3] http://clarkdave.net/2015/02/historical-records-with-postgresql-and-temporal... Esteban A. Maringolo

2016-04-23 12:13 GMT-03:00 Cédrick Béler <cdrick65@gmail.com>:

...

Sure, but 1) that's not a lot

2) do you even know if you need interactive stuff or if batch processing is ok?

interactive I would say… but hard to be certain right now as it depends on design choices… do we cache ? do we aggregate past data ? extra indexes ? I’ll see later. I want something simple, keep everything… and query according to time interval, areas (contexts)…

But yes for now this is pointless to look for something optimal and I’ll use a dictionary as it will be small at start.

Cheers,

Cédrik

-- Damien Pollet type less, do more [ | ] http://people.untyped.org/damien.pollet

Hi Robert,

Have you considered seeing if there are any Voronoi diagram packages in one of the repositories? I believe there is a fair bit of research into algorithms. You search use of spaciotemporal collated data sounds very interesting and there is a segment on computation over segments in this slide deck, that might be something, I don't know: http://graphics.stanford.edu/courses/cs368-06-spring/handouts/Delaunay_2.pdf. Certainly there is utility on the graphics side to use a 4D quadratic model (with GPU accel) and may well be modeled already in squeak/Pharo. Would't that be something!

Thanks for the links, very interesting read. I’ll have a closer look if I need to develop proper algorithms. Cheers, Cédrik

Regards, Robert

On 04/23/2016 01:29 PM, Cédrick Béler wrote:

...

Hi Esteban,

Thanks a lot, I think I’ll try your History package, it seems to be a very good starting point (instead of hacking it myself). I’ll try it soon.

Thanks for all the information ;)

Cheers,

Cédrik

...

Le 23 avr. 2016 à 18:28, Esteban A. Maringolo <emaringolo@gmail.com> a écrit :

Maybe instead of having a Dictionary, you can use my History package [1]. It allows you to add elements to "the history", and the History class will provide certain "lookup" strategies depending on how you want to query it.

It is a trimmed down version of an utility class I used for years in commercial products where the History contained thousands of elements. This version uses linear search, my previous implementation used binary search which was significantly faster with lots of elements in the collection.

Of course it doesn't solve your spatial queries needs, I don't know if there is something in Smalltalk for that other than the distance between two coordinates[2], PostgreSQL 9.2 has some support for "temporal" data/tables which you could combine with PostGIS if you need to combine a spatial query with a temporal one [3].

Regards,

[1] http://www.smalltalkhub.com/#!/~emaringolo/History [2] http://pastebin.com/ThKDXCKK [3] http://clarkdave.net/2015/02/historical-records-with-postgresql-and-temporal... Esteban A. Maringolo

2016-04-23 12:13 GMT-03:00 Cédrick Béler <cdrick65@gmail.com>:

...

Sure, but 1) that's not a lot

2) do you even know if you need interactive stuff or if batch processing is ok?

interactive I would say… but hard to be certain right now as it depends on design choices… do we cache ? do we aggregate past data ? extra indexes ? I’ll see later. I want something simple, keep everything… and query according to time interval, areas (contexts)…

But yes for now this is pointless to look for something optimal and I’ll use a dictionary as it will be small at start.

Cheers,

Cédrik

-- Damien Pollet type less, do more [ | ] http://people.untyped.org/damien.pollet

-- Robert . .. ... ^,^

I don't have a data structures book handy, but how about 3 SortedCollections? (Assuming 3 dimensions: latitude, longitude & time). It would support a reasonably efficient binary search, and allow for areas and time ranges. Regardless of which solution you choose I agree that it would be a useful general class, so please package it separately. Cheers, Alistair (Sent from my mobile) On 23/04/2016 1:47 PM, "Cédrick Béler" <cdrick65@gmail.com> wrote:

A dictionary with keys being the timestamp or the spatiotemporal object would probably do it... I think I’ll do that but I wonder if there are better solutions out there ^^.

Cheers,

Cédrik

On Sat, Apr 23, 2016 at 02:13:22PM +0200, Cédrick Béler wrote:

Hi Alistair,

Thanks, this sounds like a nice suggestion.

I have to think about it. Adding altitude would be also interesting in some cases but not as a start (quite limited usage).

When you say to package it separately, you’re talking about Geolocation, Spatiotemporal classes ? or also the collection ?

My impression was that the Geolocation & Spatiotemperal classes already exist (and presumably are already packaged), so I was thinking of the collection class (which would have the geolocation and spatiotemperal as dependencies).

I can try something but I think this will deserve more « computational thinking » power than I have ^^

Me too, but having something is still better than nothing, and maybe someone will provide ideas for improvements. Cheers, Alistair

I agree with Alistair; a pattern like EventSourcing works well for building efficient query structures for a set of data along different as-yet-to-be-determined dimensions. In Pharo terms, you can implement this using a EventStream that announces new entries, then install announcement handlers each updating a dimension-specific data structure. Also makes it easy to add new dimensions if you find you need them; simply add a new handler and replay the EventStream (with the other handlers temporarily disabled). Cheers, Henry

On 23 Apr 2016, at 2:13 , Cédrick Béler <cdrick65@gmail.com> wrote:

Hi Alistair,

Thanks, this sounds like a nice suggestion.

I have to think about it. Adding altitude would be also interesting in some cases but not as a start (quite limited usage).

When you say to package it separately, you’re talking about Geolocation, Spatiotemporal classes ? or also the collection ? I can try something but I think this will deserve more « computational thinking » power than I have ^^

Cheers,

Cédrik

...

Le 23 avr. 2016 à 13:57, Alistair Grant <akgrant0710@gmail.com <mailto:akgrant0710@gmail.com>> a écrit :

I don't have a data structures book handy, but how about 3 SortedCollections? (Assuming 3 dimensions: latitude, longitude & time).

It would support a reasonably efficient binary search, and allow for areas and time ranges.

Regardless of which solution you choose I agree that it would be a useful general class, so please package it separately.

Cheers, Alistair (Sent from my mobile)

On 23/04/2016 1:47 PM, "Cédrick Béler" <cdrick65@gmail.com <mailto:cdrick65@gmail.com>> wrote: A dictionary with keys being the timestamp or the spatiotemporal object would probably do it... I think I’ll do that but I wonder if there are better solutions out there ^^.

Cheers,

Cédrik

Hi Cedrick, welcome back in the community.

Thanks, I was not very far though ^^

...

For a project I’m starting to prototype, I need collections where objects are inserted according to an index that is a spatiotemporal object.

The idea is that each time a person add an « information" in this collection, he does it a a given place and time and I want to be able to query the collection easily according to place or time (or both).

I’m hacking it right now but I wonder if people have ideas on that subject. I’m also interested in collection that that are indexed by the timestamp of the insertion.

For the implementation of spatiotemporal classe, I choose to use a ZTimestamp and a Geolocation object. Geolocation is quite simple and is responsible among other to get the timezone, but of courses coordinates (or eventually areas).

For the collection, I’m still wandering… Something like an OrderedCollection with another internal array to store associated spatiotemporal(s)… Will hack something but I’d love to hear others ideas.

You mean something like a timeseries ? I start to work on a basic TimeSeries class quite similar to the one you find in Panda: http://pandas.pydata.org/pandas-docs/stable/timeseries.html <http://pandas.pydata.org/pandas-docs/stable/timeseries.html>

I don’t really know, more a geospatial timeserie but It might be interesting. We’ll exchange on that subject I guess. Cheers, Cédrik

-- Serge Stinckwich UCBN & UMI UMMISCO 209 (IRD/UPMC) Every DSL ends up being Smalltalk http://www.doesnotunderstand.org/