I try to download the state borders of France (a few dozen states, not big data). Indeed I look for borders I can upload in my postgres database to localize POIs. OpenstreetMap seemed to be the good data source so I have tried to learn Overpass QL but it seems harder than I thought to do so... After some wiki reading I came to this:
way["name:en"="France"];
way["type"="boundary"];
way["boundary"="administrative"];
way["admin_level"="4"];
But the query endless runs... I am not sure about the query I made, is this the good syntax ? Thanks
There are several issues with your query:
Administrative boundaries are frequently modeled as relations, rather than ways in OSM. So querying for ways way[...] will not return the result you're looking for.
To fetch elements which have have several tags, you need to combine them like [key1=value1][key2=value2]. You current query would query ALL ways WORLDWIDE with type=boundary and then again WORLDWIDE all ways with admin_level=4. Obviously this is both very expensive and not what you're looking for.
out statement is mandatory to return some result. In your case, the query would in fact run, but it would never return anything.
My recommendation is to use the following query instead:
rel["ISO3166-2"~"^FR"]
[admin_level=4]
[type=boundary]
[boundary=administrative];
out geom;
Try it in overpass turbo: http://overpass-turbo.eu/s/lnv
Related
Is it possible to export all ways of piste:type and aerialway? Or maybe query these for a ski resort?
I would like to show these on a map in an iOS app. It would be nice to be able to export these sets either for each resort or whole country.
If this is not possible, can one query a resort or a country, in some way?
I have read some of the documentation, including on the API, but still is quite unsure how to correctly query the API or export these sets.
What I essentially need, is described with this query I have setup:
http://overpass-turbo.eu/s/wvo
Thanks
Pentaho version : bi server CE 6.1
I'm new to pentaho universe and I found myself stuck in finding documentation to create a cde dashboard. Just to be clear, I have no idea of what is the good way to create cde dashboard, but i tried many things based on tutorials found pretty much everywhere
What i have done so far
From this data model
I already created a dynamic chart with "sql over sqljdbc" datasource.
Here is my query (and the result behind in picture)
SELECT (select survey_type from survey where id = pr.form_type) as "form type",
pr.date as "Date",
count(pr.id) as "Form number"
FROM result pr
inner join district pd on pr.district_id=pd.id
inner join departement pdep on pd.departement_id=pdep.id
inner join region pre on pdep.region_id=pre.id
WHERE pre.region_text = ${region}
GROUP by date,form_type
ORDER by date;
Dashboard generated by the query - Form number by date, type and region (set dynamically)
What I want to achieve
I want to do this kind of chart : community.pentaho.com/ctools/ccc/#type=bar&anchor=small-multiple-bars or community.pentaho.com/ctools/ccc/#type=bar&anchor=stacked-bar (sorry i don't have enough reputation to post more than 2 links) with a "sql over jdbc" datasource
Can anyone give me an example of sql request to achieve that ? (preferably with the sql request given up on this post with some modification.I tried this but it does not work as expected:
SELECT (select survey_type from survey where id = pr.form_type) as "form type",
pr.date as "Date",
pre.region_text as region,
count(pr.id) as "Form number"
FROM result pr
inner join district pd on pr.district_id=pd.id
inner join departement pdep on pd.departement_id=pdep.id
inner join region pre on pdep.region_id=pre.id
GROUP by date,form_type,pre.id
ORDER by date;
)
And where can i put the code given behind this example to previsualize it in my own instance of pentaho ? I need to know how to reproduce it
What i want to know
The good way to do cde chart on pentaho :
how the query need to be formatted ? (how fields are organised on dashboard, number max of fields...)
what is the difference between mdx queries and sql queries and purpose ?
what is the best way to do chart between those two types (mdx and sql) ?
how can i transform my relational database in mondrian cube if i want to use mdx queries (or what i should do is to redesign the database in datawarehouse using kettle ?)
Thank you for your answers.
First of all you should realize that you're asking alot here. Having said that you've pretty much done what I did when I first started with Pentaho which was experiment. Alot.
Regarding your questions I have some links which should help you (if you haven't checked them already)
http://pentaho-bi-suite.blogspot.be/2014/01/inter-panel-communication-in-pentaho.html
http://holowczak.com/getting-started-with-pentaho-community-edition-dashboard-editor-cde/
The first link is a very good blog on which I have found several answers regarding dashboards.
The second link is more of an overal tutorial.
There is no general "best way" (apart from applying general best practices ofcourse) for creating dashboards. I suggest you keep trying (getting to know all of the properties and settings along the way) and find out what method works best for you.
Regarding your questions about MDX and Mondrian, I haven't had much experience in these area's but as I understand it MDX queries are based off of Mondrian cubes which you prepare in the Mondrian Schema Workbench of Pentaho.
http://mondrian.pentaho.com/documentation/olap.php
I believe this should answer (atleast some of) your questions. Trying many different things and experimenting will get you quite far as you'll catch up with plenty of small things one at a time.
I will elaborate a little bit on this.
As dooms stated, you ask a lot of things here but I am glad you are trying to create some great dashboards.
In order to format charts and tune them, I remembered I had to learn some JavaScript/JQuery.
The difference between SQL and MDX. They are completely different,
even when sometimes the syntax looks similar. You use SQL to query
relational databases whereas MDX is used to query Cubes. If you don’t
have cubes in place you need to use SQL of course. If not, you should
ask the cube developer to introduce you to this world. Basically
cubes are good at aggregating data and allows to easily interact and
perform ad-hoc analysis, it is intended for business analyst to let
them better explore the data. I am a MDX fan, but I would recommend
you to explore new alternatives to multidimensional cubes, like
tabular models or other in-memory technologies.
The best way to do a chart has nothing to do with MDX or SQL. It depends where your data is stored. The most important thing is to have a good data model behind.
Again, depending on your architecture, you should have a multidimensional model in your data mart, without snow flake if possible. That allows you either to build easy SQL queries and a straight forward cube design. Designing cubes required some extra skills. I would try to have a clean data model and then start to evaluate if a cube is required.
I hope I give you some lights, it is not easy to answer the broad questions you asked. Important is to define the scope of your project.
Kind Regards,
I want to understand if I can do the following thing with NoSql in any way. I will take flights as example.
Lets say I have table or collection of flights with the following info:
...
{ from:XXX, to:YYY, date:01-01-2016 }
{ from:YYY, to:XXX, date:02-02-2016 }
...
I need to be able to perform something like self join to find the full route :
{from:XXX, to:YYY, outbound:01-01-2016, inbound:02-02-2016}
the table should have a lot of from and to locations.
Is it possible to do it with no relational DB?
Is it possible to do it with no relational DB?
That's the wrong question to ask. The idea of NoSQL is to use specialized data stores for specific problems, instead of attempting to solve every problem with the same tool.
Your use case is unclear, however - depending on what data you use to query, you could simply do two queries and merge the result(s), or use a simple $or query (in mongodb) to query for paths back and forth. There's dozens of ways to solve this with all kinds of tools, but it depends on the exact problem you want to solve.
The example of flights is not even a good fit for RDBMSs, because this is usually a routing problem where it might be allowed (or necessary) to combine two or more flights for each direction - neo4j might be the simpler tool for graph problems (note that I'm not saying 'better', because that can mean many things...)
Here is an efficient way to do this in AWS DynamoDB.
Create a table with the following schema:
HashKey: From_City-To_City
RangeKey: Time
So in your case your table would look like:
HashKey RangeKey
XXX-YYY 01-01-2016
YYY-XXX 02-02-2016
Now given a flight from XXX to YYY on 01-01-2016, you can find the return flight by doing a DynamoDB query like this:
HashKey=="YYY-XXX" and RangeKey > "01-01-2016".
This query should be very efficient because the hash key "YYY-XXX" is already defined and range key is sorted/indexed. So you can have tons of flight info in your table, but your query execution time should stay (mostly) the same regardless of the growth in table size.
I'm trying to figure out what's the best solution to find all nodes of certain types around a given GPS-Location.
Let's say I want to get all cafes, pubs, restaurant and parks around a given point X.xx,Y.yy.
[out:json];(node[amenity][leisure](around:500,52.2740711,10.5222147););out;
This returns nothing because I think it searches for nodes that are both, amenity and leisure which is not possible.
[out:json];(node[amenity or leisure](around:500,52.2740711,10.5222147););out;
[out:json];(node[amenity,leisure](around:500,52.2740711,10.5222147););out;
[out:json];(node[amenity;leisure](around:500,52.2740711,10.5222147););out;
[out:json];(node[amenity|leisure](around:500,52.2740711,10.5222147););out;
[out:json];(node[amenity]|[leisure](around:500,52.2740711,10.5222147););out;
[out:json];(node[amenity],[leisure](around:500,52.2740711,10.5222147););out;
[out:json];(node[amenity];[leisure](around:500,52.2740711,10.5222147););out;
These solutions result in an error (400: Bad Request)
The only working solution I found is the following one which results in really long queries
[out:json];(node[amenity=cafe](around:500,52.2740711,10.5222147);node[leisure=park](around:500,52.2740711,10.5222147);node[amenity=pub](around:500,52.2740711,10.5222147);node[amenity=restaurant](around:500,52.2740711,10.5222147););out;
Isn't there an easier solution without multiple "around" statements?
EDIT:
Found This on which is a little bit shorter. But still multiple "around" statements.
[out:json];(node["leisure"~"park"](around:400,52.2784715,10.5249662);node["amenity"~"cafe|pub|restaurant"](around:400,52.2784715,10.5249662););out;
What you're probably looking for is regular expression support for keys (not only values).
Here's an example based on your query above:
[out:json];
node[~"^(amenity|leisure)$"~"."](around:500,52.2740711,10.5222147);
out;
NB: Since version 0.7.54 (released in Q1/2017) Overpass API also supports filter criteria with 'or' conditions. See this example on how to use this new (if: ) filter.
Is there such a concept as subcollections in mongo, something like a subdocument but supports the full crud api? I would like to organize my db to perform queries like this:
db.games.pong.leaderbords.find({score:{'$gt':99}})
In other words is there any hierarchy to collections or must I create a fully descriptive name for each collection, as in:
db.pongLeaderboard.find({score:{'$gt':99}});
EDIT: As Nicolas pointed out the dot notation is allowable. What I meant to ask is can I do this and have games and pong be proper collections in their own right so I could still do something like
db.games.find({name:'pacman'})
It's perfectly legal for collection names to contain the . character, so it's entirely possible to organise your data such that your first query is correct.
I'm fairly sure that creating the collection games.pong.leaderbords does not create games, games.pong or pong though, so this might not answer your problem.
This type of question is terribly easy to answer for yourself though - just type your query in MongoDB and see what happens. If it fails, it's not possible. If it doesn't, it's possible. MongoDB is good that way. Not only does that give you a definite answer, it also gives you an immediate answer without having to wait for someone to try and type your query and post the result.
What I meant to ask is can I do this and have games and pong be proper collections in their own right so I could still do something like
If I understand you right then no. Those two "subcollections" will have no reference to each other as such, unless you have actually created a games collection with data in (db.games.ping.xx doesn't count) then this will not work.