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0
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1answer
16 views

Polygon area calculation in Ruby (on Rails, rgeo, PostGIS and GEOS) in sqare meters

In a Ruby-on-Rails application, I need the area in square meters (or any other surface measure, be it ares, hectares, square kilometers, but not in pseudo surface measure like square degrees) of a ...
0
votes
0answers
18 views

Refresh Openlayers vectorLayer every 5 seconds with jQuery and Ruby

Ich want to refresh my vectorLayer in OpenLayers every 5 Seconds using a jQuery. How do I have to do this? The data for the Layer is stored in a Ruby KML. Just look at the Code. Ruby method for the ...
0
votes
1answer
24 views

Create KML in Ruby with ruby_kml and use in Javascript

I want to create a KML in Ruby and use it with Openlayers. But Openlayers only wants a real KML file. It's complicated to explain. Just look at my Code: In my Controller I have the following method ...
0
votes
1answer
293 views

Phusion Passeger Error

so i am installing the cartodb platform locally i have followed all the procedures succesfully but i have a phusion passenger spawn error. I am looking for working solutions and i haven't any to be ...
0
votes
1answer
157 views

Running CartoDB Server Stack

We're attempting to download and run the CartoDB stack on an Ubuntu Amazon EC2 instance dedicated just for it. So we've begun from a bare bones OS install. We've gone through the install/configure ...
1
vote
1answer
91 views

Why are my points being flipped or mirrored when I convert from DMS to DD?

I have a collection of crash data that provides latitude and longitude in degrees, minutes, and seconds that I'm converting to decimal degrees using: (degrees + (minutes/60.0) + (seconds/3600.0)) ...
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vote
0answers
140 views

Building a road path using openlayers and shapefiles? [closed]

I'm looking to learn OSM and Openlayers. From what I can tell, I need OpenLayers to display the map on a website and I need shapefiles to do any manipulation on the map regarding its topographical ...
0
votes
0answers
185 views

error occured when importing file on cartodb local host

Logged in as development user. Not able to import a .zip or a csv file. Ruby console has this error log 1.9.2p320 :004 > DataImport[1].log 2014-01-07T05:44:44Z || Using database connection with ...
1
vote
0answers
133 views

Geocode incredibly quickly but inaccurately

I have a Rails 4 app that needs to be able to geocode a large number of places very quickly, but not with any high degree of accuracy. Accurate to a few miles would be fine, I really just need the ...
4
votes
1answer
258 views

intersection between two multipolygons yielding anomalous GeometryCollection object full of LineString's & Polygon's (trying to get intersect area)

Normally when I call the #intersection method on a multipolygon to find the intersection shape on another multipolygon I get a multipolygon returned back to me. Either that or something else I can ...
2
votes
2answers
2k views

Attempting to use ST_DWithin to locate objects within a given distance of meters using SRID 4326

I'm a Rails developer with minimal GIS experience, working with PostGIS and the RGeo gem. I'd like to find all of the cows within 500 meters of my current location. So, I'll create a model for my ...
0
votes
1answer
914 views

How to fix “Connection failed - Check settings and try again” when connecting to PostGIS?

I have Postgres running via Postgres.app on rails already and am trying to connect QGis to the database. PostGIS is working already. (questions already found online deal with this issue only) I do ...
3
votes
1answer
579 views

When trying to convert lon/lat (curved) coordinates to projected (flat) coordinates with ruby, the second (y axis) projected coords are inaccurate

So I have created a polygon using Google Earth pro. I've exported it into a kml file, which I can then parse using ruby's XML/HTTP-parsing Nokogiri gem into an array of WKT points (LinearRing) thats ...
2
votes
1answer
133 views

Which fields are standardized to describe a ShapeFiles feature?

I would like to store data into a database which is available here either as JSON or as ShapeFiles. The JSON looks something like this: { "type": "FeatureCollection", "features": [ { ...
8
votes
1answer
2k views

Pros and cons of using Ruby/Rails/RGeo or Python/GeoDjango for a web based GIS

We're at the investigation phase of creating a web based GIS. We're assessing options for an ORM to use in all of our backend import/export and processing routines. From my research, GeoDjango appears ...
1
vote
0answers
382 views

Can I use RGeo::Point data in PostGIS queries without multiple conversion?

How can I represent RGeo::Point ( CAPI implementation ) in some way where I don't have to convert it once more in Sql? Now I have something like this: class Poly scope :enclosing ->(geom) do ...
1
vote
1answer
350 views

Point plus distance along great circle using RGeo or WKT

I'm racking my brains (and google) trying to figure out how to get RGeo to do the following geospatial calculation: Imagine I start off at some arbitrary geographic point (let's say (45, 45) which ...
1
vote
2answers
106 views

Offline data and less space with Ruby

I have a very specific problem. I am trying to build an offline map on leaflet, rhomobile(based on ruby) and OSM data. The problem is that I am making now a offline layer images folder with the city ...
3
votes
4answers
883 views

Algorithm for finding population for a given center point and radius in US

Here is what I have The population data aggregated by zip code given by US Census. Here is what I am doing right now: Reverse geo code the center point to find the zip code of the center point. ...
11
votes
9answers
3k views

What are the advantages of using Rails for a GIS/mapping application?

I've heard some good things about Rails, but I don't know much about it yet. There are only a few questions about Rails on GIS.SE (and there's not even a Rails tag). Is it worthwhile to learn about ...