New answers tagged

0

Surely, the preferred answer is (1), i.e., have clients do the "right thing". A good case to consider is the polygon representing the continent of Antarctica approximated by this kml file <kml> <Folder> <name>Antarctica</name> <Placemark> <name>Antarctica</name> <Polygon> ...


0

Mapzen has a really cool geocoding service that allows you to query the name of the place to get an XY coordinate. (https://mapzen.com/documentation/search/search/). You can get a free API key from their developers page which will allow you to make 30,000 queries per day at 6 per second. (https://mapzen.com/) Here's a function that will return the XY ...


4

Speaking purely from a data storage and analysis perspective, the geography type for PostGIS was designed with the antimeridian in mind (among several design goals). There are several functions specifically designed for the geography type. For instance, consider a LineString across Taveuni, Fiji (mapped with Great Circle Mapper), which straddles the ...


0

Here are a few sites you may want to check out: http://catalog.data.gov/dataset/fcc-geographic-information-systems http://www.cellreception.com/towers/ http://opensignal.com/ http://www.towerco.com/simplicityfound/


2

You could try using the Google Maps geocoding API (https://developers.google.com/maps/documentation/geocoding/intro). It works well, but there's a limit to 2,500 geocodes per user per day. Here's a function to help geocode using Google. If you go over the daily query limit, or over the per second limit of 10 per second you'll get an error message instead ...


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A good alternative to the official Scihub is the mirrored Sentinel-2 data on Amazon Web Services. Sentinel-2 on AWS This has the advantage of better uptime and the products are allready saved in their MGRS tiles, which makes downloading a lot faster. The data is stored in a public bucket with the scheme tiles/[UTM code]/latitude ...


2

I received help from an application developer at JNCC. I will post their answer here to help others. My problem was that I needed to escape the $ character before value. so the wget command should read (using the apihub, which you could replace with dhus): wget --no-check-certificate --user=username --password=usrpass ...


2

Though I used Leaflet in my webGIS application, OpenLayers has much more advantages over Leaflet. For example if you want to use your application in mobile devices, OpenLayers is a must for the time being. There are lots of resources related with OpenLayers, however I think developing application with Leaflet is easier than OpenLayers (it is easier to read ...


1

Putting it all together for those who are interested CREATE OR REPLACE FUNCTION foo.map_api() RETURNS trigger AS $BODY$BEGIN NEW.link:= 'http://www.openstreetmap.org/#map=17/' || ROUND(ST_X(new.geom)::NUMERIC,0)::TEXT || '/' || ROUND(ST_Y(new.geom)::numeric,0)::TEXT; RETURN NEW; END;$BODY$ LANGUAGE plpgsql VOLATILE COST 100; ALTER FUNCTION ...


1

Yes, I think accessing the WMS or WFS services of the Nationaal Georegister is the way to go. Just for reference, here is the link to the WMS service: https://geodata.nationaalgeoregister.nl/napinfo/wms? I had no trouble accessing it in QGIS, and using the Identify button, I could access the true NAP data for points. Your question is not so much about ...


1

You probably want to do something like: UPDATE foo set link= 'http://www.openstreetmap.org/#map=17/' || ROUND(ST_X(geom)::NUMERIC,0)::TEXT || '/' || ROUND(ST_Y(geom)::numeric,0)::TEXT


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taginfo counts 104000 nodes and 206000 ways tagged with leisure=playground. That is not a very huge amount of data, but you should query both data types. It would be best to prefetch them, put them in an extra database, and let the users query that online. You could build centroids on the closed ways to reduce the data amount. If the data can be "a few days ...



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