[QGIS-Developer] [Qgis-user] Refresh layer at interval

Richard Duivenvoorde rdmailings at duif.net
Mon Nov 2 03:23:13 PST 2020


I think you hit an old issue:

https://github.com/qgis/QGIS/issues/28282
and
https://github.com/qgis/QGIS/issues/28744

Not sure if I can tackle it, but I can give it a try.
If a core-dev has a clue, please let me know...

I think this should work, as this makes it supereasy to have a 'moving map'..

Regards,

Richard Duivenvoorde


On 11/1/20 9:24 PM, nagyrobi_r at yahoo.com wrote:
> 
>     Hi All!
> 
>     I am trying to understand the behavior of Layer->Render-> Refresh layer at interval in QGIS
> 
>      1. I sat up a flask rest api which serves a geojson.
>      2. I added the geojson to QGIS via Add Layer-> 
>          1. a. Protocol HTTP/cloud/etc 
>          2. b. Type: HTTP 
>          3. c.URI: localhost/points.geojson The points are represented on the map correctly
>      3. I changed the layer->Properties->Rendering-> Refresh layer at interval (5 sec)
> 
>     I would have expected that there would be a call every 5 seconds towards the server and the map data would be updated accordingly. But the layer does not get refreshed. I don't see any changes neither when I remove a point from the json file on my local drive, nor if I change an attribute. If I press F5 then the canvas refreshes and it automatically loads the new data and I can see the changes. Is this the behavior that is wanted or am I misunderstanding the function of this tool? It seems like the data is cached somewhere?
> 
>     |from flask import Flask from flask_restful import Api, Resource import json app = Flask(__name__) api = Api(app) class point(Resource): def get(self): with open('C:/points/venv/src/points.geojson') as json_file: data = json.load(json_file) return data api.add_resource(point,"/points.geojson") if __name__=="__main__": app.run(debug=True)|
> 
>     |Robert Nagy|
> 
> 
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