I need to get from overpass-api all the data about one, specific public transport line. Let's say it has a number 148 in my city.
I use something like this example below
but this gives me combined ways of forward and backward routes. How can I get them separately?
<osm-script output="json">
<union>
<query type="relation">
<has-kv k="ref" v="148"/>
<bbox-query s="54.21466404047702" w="18.270263671875" n="54.503143645746924" e="18.840179443359375"/>
</query>
<recurse type="down" />
</union>
<print mode="skeleton" order="quadtile"/>
</osm-script>
You could filter by role:
http://wiki.openstreetmap.org/wiki/Overpass_API/Overpass_QL#Recurse_.28n.2C_w.2C_r.2C_bn.2C_bw.2C_br.29
Here is an example for other route, which have forward and backward ways.
[out:json][timeout:25];
(
//get relation
relation["route"="bus"][ref=157]({{bbox}});
// get ways with particular role
way(r:"forward");
// you may also add ways with empty role if you want
// give role as an empty string
//way(r:"");
// get way nodes.
// We can't use >; operator, because it will recurse to
// all relation members.
node(w);
);
out skel qt;
Try it on overpass-turbo:
http://overpass-turbo.eu/s/a4F
Related
I need to implement a download feature. It will read the data in the react-data-grid (adazzle), respecting the current columns, filters and sort, and create an array json (or comma separated strings) I can then pass to the react-csv module.
I have a data structure populated from the backend but it is not filtered nor sorted. I need to be able to ask the grid for it's data on a row-by-row basis. Can anyone point me in the right direction?
Without code or some context, I can't answer with certainty...
You supply the rowGetter prop with the collection to display, or the method to get the rows to display...I'm thinking if you filtering, then most likely you've got some sort of mechanism supporting that... Either way, you can use this property's value somehow to get exactly what you see in the grid.
If you literally want to interrogate the grid, you could try adding a reference to the grid, and then see if you can ask it for the row data. I can't remember with certainty that I saw a rows prop in the grids available props via the ref, but I imagine you should be able to (**,)
...
handleExport = async => {
const exportRows = rows;
// const exportRows = getRows(initialRows, filters);
// const exportRows = this.state.gridref.CurrentRows DISCLAIMER:CurrentRows is just for giving the idea... check out the ref yourself to see if it's possible to get the rows via the grid refs props.
downloadCSV( exportRows )
}
...
<ReactDataGrid
ref={input => {this.state.gridref = input}}
columns={columns}
rowGetter={i => rows[i]} // or maybe rowGetter={i => getRows(initialRows, filters)[i]}
rowsCount={rows.length}
onGridSort={(sortColumn, sortDirection) =>
setRows(sortRows(initialRows, sortColumn, sortDirection))
}
/>
I've only ever [set / initialised] the this.state.gridRef prop in my constructor, but I guess you could also [set / initialise] it in your componentDidMount as well...
initialise like this:
this.state.gridRef = React.createRef()
function updateFirebase(){
const fb=firebase.database().ref()
//get field values
author = document.getElementById('uname').value
user_email = document.getElementById('umail').value
data = {author, user_email}
//update database
fb.child('Article/').update(data);
}
</script>
I have problem with my code. I want to update the data inside a table named "Article". Article has generated items with a unique key/id and each key has its own content. Lets say I want to be able to edit the "author" or change the "title", the problem is they each have a randomly generated key/id that I cant access. for example that "-LS39kReBHrKGqNj7h_". I can only save the data inside the "Article" tree but I cant change the "author" or the "title". How do i get a workaround this so I can change those properties?
Here is how my firebase looks like
It depends whether you have the record reference on the frontend before update or not (whether you have fetched it before you are trying to update it).
But generally, you have two options
You can store the key reference as an "id" field on the object.
To achieve that, you need two step process when creating the record at the first place
// Creates a new record in DB and returns it to you. Now you can get the "key"
const newRecord = firebase.database().ref('TABLE_NAME_REF').push();
newRecord.set({
id: newRecord.key
...
});
This is great if you fetch the list of records on the frontend and then you want to update one of them. Then you can just build the ref path like this
fb.child('Article/' + record.id ).update(data); // where record is the prefetched thing
You need to find the element based on its fields first. And once you have it, you can update it right away.
To achieve this, you can simply do something like:
firebase.database()
.ref('TABLE_NAME_REF') // let's say 'Article'
.orderByChild('RECORD_KEY') // Let's say 'author'
.equalTo('KEY_VALUE') // let's say 'zoranm'
.limitToFirst(1)
.once("value")
.then(res => {
// You need to loop, it always returns an array
res.forEach(record => {
console.log(record.key); // Here you get access to the "key"
fb.child('Article/' + record.key ).update(data); // This is your code pasted here
})
})
I have in my bucket a document containing a list of ID (childList).
I would like to query over this list and keep the result ordered like in my JSON. My query is like (using java SDK) :
String query = new StringBuilder().append("SELECT B.name, META(B).id as id ")
.append("FROM" + bucket.name() + "A ")
.append("USE KEYS $id ")
.append("JOIN" + bucket.name() + "B ON KEYS ARRAY i FOR i IN A.childList end;").toString();
This query will return rows that I will transform into my domain object and create a list like this :
n1qlQueryResult.allRows().forEach(n1qlQueryRow -> (add to return list ) ...);
The problem is the output order is important.
Any ideas?
Thank you.
here is a rough idea of a solution without N1QL, provided you always start from a single A document:
List<JsonDocument> listOfBs = bucket
.async()
.get(idOfA)
.flatMap(doc -> Observable.from(doc.content().getArray("childList")))
.concatMapEager(id -> bucket.async().get(id))
.toList()
.toBlocking().first();
You might want another map before the toList to extract the name and id, or to perform your domain object transformation even maybe...
The steps are:
use the async API
get the A document
extract the list of children and stream these ids
asynchronously fetch each child document and stream them but keeping them in original order
collect all into a List<JsonDocument>
block until the list is ready and return that List.
I have a User model which has an array inside of it. This array is used to store points the user has scored in various activities. It basically looks like this:
<ActiveRecord::Relation [#<User id: 1, fullname: "Kaja Sunniva Edvardsen", points: [0, 4170, 3860, 2504, 2971, 3859, 4346]>, #<User id: 2, fullname: "Alexander Lie Sr.", points: [0, 3273, 3681, 2297, 2748, 4202, 3477]>]>
I want to sort all Users by the different values in the points array to be able to create ranking list for each of the different activities, points[0], points[1], etc...
Sorting by points[1] should return Kaja first, 4170>3273, sorting by points[6] should put Alexander first, 4202>3859
How do I do this?
As far as I know, MySQL does not have an integrated array type.
Assuming you have a model like this:
class User < ActiveRecord::Base
# ...
serialize :points, Array
# ...
end
You cannot sort with order queries, but you can try another solution (less efficient), handling the resources as an array:
User.all.sort { |user1, user2| user2.points[1] <=> user1.points[1] }
Which will return an array instead of an ActiveRecord query. Also, bear in mind that this code will not handle nil values (i.e. What if an user only have 2 elements in points?).
I'm using an Express server with RethinkDB, and I want to send in multiple coordinates into my 'locations' table on RethinkDB and create an r.polygon(). I understand how to do the query via RethinkDB's data explorer , but I'm having trouble figuring out how to send it via JSON from the client to the server and insert it through my query there.
I basically want to do this:
r.db('places').table('locations').insert({
name: req.body.name,
bounds: r.polygon(req.body.bounds)
})
where req.body.bounds looks like this:
[long, lat],[long, lat], [long, lat]
I can't send it in as a string because then it gets read as one single input instead of three arrays. I'm sure there's a 'right in front of me' way, but I'm drawing a blank.
What's the best way to do this?
Edit: To clarify, my question is, what should my JSON look like and how should it be received on my server?
This is what RethinkDB wants in order to make a polygon:
r.polygon([lon1, lat1], [lon2, lat2], [lon3, lat3], ...) → polygon
As per the suggestion, I've added in r.args() to my code:
r.db('places').table('locations').insert({
name: req.body.name,
bounds: r.polygon(r.args(req.body.bounds))
})
Edit
Ok, I was dumb and had a typo in one of my coordinates!
Sending it as an array of arrays and wrapping it in r.args() on the server side works.
What you need is r.args to unpack the array into arguments for r.polygon. https://www.rethinkdb.com/api/javascript/args/
With assumption that req.body.bounds is:
[[long, lat],[long, lat], [long, lat]]
And you are submit a raw JSON string from client.
You first need to decode the JSON payload, and get the bounds field, wrap it with args as following:
var body = JSON.parse(req.body)
r.db('places').table('locations').insert({
name: req.body.name,
bounds: r.polygon(r.args(body.bounds))
})