Tagged Questions

1
vote
2answers
76 views

How to add a polygon from GeoJson into Leaflet?

I try to use the following function to add polygons to my Leaflet map. function polygon(geojson) { alert(geojson); // alert for testing layer = L.geoJson(geojson); layer.addTo(map); } ...
2
votes
1answer
44 views

Can Geoserver return the raster value of a lat/lon point

I have a GeoTIFF published by Geoserver 2.2 and being used by Leaflet via WMS. How can I get Geoserver to return the raster value at a lat/long point? I'm guessing it has to do with using WCS, but ...
1
vote
0answers
54 views

Creating polygons for a choropleth map using PostGIS

I have a grid of points, each with a value to it as shown in the image below. The data was retrieved from PostGIS and rendered in Quantum GIS. The final result should be a polygons of a choropleth map ...
2
votes
1answer
72 views

Value at a particular spot on Geoserver Heatmap

Geoserver is drawing from a PostGIS database to generate a heatmap using this SLD extension. Leaflet then overlays the heatmap over the base layer. Question: How can you determine the value at a ...
7
votes
1answer
170 views

Generating Heatmap from PostGIS

I have GIS data in a PostGIS data base and would like to generate a density map and display them on a Leaflet/Google Maps. Question: What is the recommended/typical method for doing so, without ...
1
vote
1answer
179 views

Is it possible to use Leaflet, PostGIS and PGRouting for web mapping?

I am newbie at Open Source GIS. I have already create a web mapping using custom tiles and leaflet. I have used my my own database. Tilemill was used to create the tiles and leaflet was used to ...
1
vote
1answer
133 views

Polygon intersection with bounding box with polygon's holes intact

I am trying to serve GeoJSON FeatureCollection tiles with each feature's geometries trimmed to the tile boundary. I am working on a Leaflet plugin to re-assemble the geometries. It works by building ...
2
votes
1answer
284 views

formatting geojson from postgis data using node.js

I am trying to build a GeoJSON object from a SQL query to some GIS point data in a postgis postgresql database. A snippet of my node.js app.js is below. As it stands I understand building the type ...
2
votes
2answers
225 views

How to pull lat/lng from a map canvas and update a database

So if i want to pull out lat/lngs after user clicks on a map canvas (lat/lngs are pulled using any javascript API (leaflet, wax etc.) and add this to a postgresql database using a query, how do i do ...
35
votes
7answers
5k views

How to create Vector Polygons at the same amazing speeds GISCloud is able to render them?

EDIT (outlining new bounty added): I have added the largest bounty possible to this question in hope of getting a very detailed answer. Your solution should outline a step-by-step guide utilizing open ...