topic Re: Create Line Map visualization from coordinates in App Development

Create Line Map visualization from coordinates

Enriquemmesteo — Sat, 16 Nov 2024 01:44:22 GMT

Hello everyone,

The case is this:

We have a file with many fields with the information of train stations. Some of those fields relevant to this issue are "Station","Line","Latitude","Longuitude".

These coordenates belong to each of the stations. A line is conformed by various stations. Here is a little example:

What I currently do is add this line in the script GeoMakePoint([Latitude],[Longitude]) as Coordinates

and then in the map visualization I add Coordinates as point layer. If I have Coordinates in the data of the visualization it shows all the points. If I use the Line as dimension, it only shows a few of the points.

But really what I need to do is create a line layer instead of a point layer on the map visualization. I need a visualization showing lines joining all the dots for each "Line". In the previous example it would show a 3 lines conformed by joining the coordinates of their stations.

Anyone can help me with this?

Thanks in advance!

Re: Create Line Map visualization from coordinates

lironbaram — Wed, 05 Aug 2020 10:33:50 GMT

you can create the line in the script or in the map

for calculating the line in the front end, use this expression and line as dimension

='[[' & concat(Coordinates,',',Station) & ']]'

Re: Create Line Map visualization from coordinates

Enriquemmesteo — Wed, 05 Aug 2020 10:50:40 GMT

Im kinda lost here. Where should that expression go to create the line layer for the map visualization?

I guess some intermediate steps could be required to join all stations from the same "Line" with their coordenates to display a line in the map, and I suppose this can't be done if we don't know the order. In the example :

To create a line for the "Line" 1: we need to join the coordinates for A, B,C in that order because A,C,B would be a different line.

Re: Create Line Map visualization from coordinates

lironbaram — Wed, 05 Aug 2020 10:53:29 GMT

you put this expression in the location field of the line layer

as for the order the line is built using the station name for the order

Re: Create Line Map visualization from coordinates

Enriquemmesteo — Thu, 06 Aug 2020 09:40:31 GMT

Hi Liron, I've tried this but it says Invalid dimension and no lines are shown in the map. I've tried some teaks to the formula but nothing works.

Any ideas what is going on?

Re: Create Line Map visualization from coordinates

lironbaram — Thu, 06 Aug 2020 13:38:25 GMT

as the dimension you should use the line field

then use this expression in the location field

Re: Create Line Map visualization from coordinates

Enriquemmesteo — Tue, 15 Sep 2020 06:47:15 GMT

Thanks Lionbaram, it worked but needs more work from our part to prepare the data correctly. These stations needs to be ordered to form the lines correctly in the map visualization

Re: Create Line Map visualization from coordinates

sfbi — Wed, 16 Sep 2020 13:59:01 GMT

thank you... helped me a lot!

Re: Create Line Map visualization from coordinates

snowman — Wed, 14 Oct 2020 04:47:40 GMT

Hi,

I have the same requirement, and may I know if your expression should be added to the Location field (under Location section) of both Start point and End point or somewhere else ?

Thanks

Re: Create Line Map visualization from coordinates

snowman — Wed, 14 Oct 2020 05:59:52 GMT

Sorry, I got it. The expression should be added in the Line geometry field.

However as @Enriquemmesteo said the stations are not all in right sequence. Can the expression be modified if a new column of station sequence (SEQ) is added so that the line would be in the right sequence of stations ?

Thanks

Re: Create Line Map visualization from coordinates

snowman — Wed, 14 Oct 2020 09:25:53 GMT

I got the solution. To modify the expression advised by @lironbaram , can add a column from the data file for station sequence (eg. Seq), then use Seq instead of Station as the sort order for concat():

='[[' & concat(Coordinates,',',Seq) & ']]'

Re: Create Line Map visualization from coordinates

Trick17 — Tue, 24 May 2022 09:22:58 GMT

thanks a lot this was really helpful !!

Re: Create Line Map visualization from coordinates

Trick17 — Tue, 24 May 2022 09:23:19 GMT

thanks, that was really helpful!