Vladimir Rybalko vladimir-rybalko

Interpolate points along lines using QGIS virtual layers

Suppose we want to interpolate a number of points along each line in a layer:

We have a column called stations that specifies how many points to interpolate on each line:

How to setup a NASA WorldWind elevation server

Introduction

This guide shows how to create a WMS server on a local VM using Apache, MapServer and elevation data sets curated by NASA. This WMS server serves as a model for a production MapServer instance to be deployed on an a network.

The guide contains a brief overview of how the WorldWind clients make requests, followed by instructions for setting up the Apache web server, MapServer and the Apache caching.

	import json
	import geojson
	from shapely.geometry import shape

	o = {
	"coordinates": [[[23.314208, 37.768469], [24.039306, 37.768469], [24.039306, 38.214372], [23.314208, 38.214372], [23.314208, 37.768469]]],
	"type": "Polygon"
	}

	s = json.dumps(o)

	import asyncio
	import psycopg2

	# dbname should be the same for the notifying process
	conn = psycopg2.connect(host="localhost", dbname="example", user="example", password="example")
	conn.set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)

	cursor = conn.cursor()
	cursor.execute(f"LISTEN match_updates;")