Author Archive

Senators Introduce Bill Requiring FCC to Collect “Consistent” Coverage Data

23/05/2017

DC Circuit Upholds FCC\’s Incentive Auction Rules

Source: Senators Introduce Bill Requiring FCC to Collect “Consistent” Coverage Data

Senators Introduce Bill Requiring FCC to Collect “Consistent” Coverage Data

23/05/2017

National Public Safety Telecommunications Council

May 11, 2017–A group of senators today introduced a bipartisan bill that would require the FCC “to collect broadband coverage data that is valid, consistent, and robust,” a news release noted. “This standardized data is necessary to ensure that policies to expand broadband deployment accurately target the unserved and underserved communities and account for the mobile coverage experience of those living in the most remote parts of the country,” the news release added.

The bill would give the FCC 180 days to adopt “regulations to establish a methodology that shall apply to the collection of coverage data by the Commission for” the universal service program and any similar programs.The bill says that the methodology would have to “(1) contain standard definitions for different speed tiers, such as the 2G, 3G, 4G, and 4G LTE tiers; (2) ensure that coverage data is collected in a consistent and robust way; (3) improve…

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Visualization tips for geoscientists – Matlab

21/05/2017

MyCarta

Introduction

In my last post I described how to create a powerful, nondirectional shading for a geophysical surface using the slope of the data to assign the shading intensity (i.e. areas of greater slope are assigned darker shading). Today I will show hot to create a similar effect in Matlab.

Since the data set I use is from my unpublished thesis in Geology, I am not able to share it, and you will have to use your own data, but the Matlab code is simply adapted. The code snippets below assume you have a geophysical surface already imported in the workspace and stored in a variable called “data”, as well as the derivative in a variable called “data_slope”.

Method 1 – with a slope mask and transparency

Some time ago I read this interesting Image Processing blog post by Steve Eddins at Mathworks on overlaying images using transparency. I encourage readers to take…

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New Matlab isoluminant colormap for azimuth data

21/05/2017

MyCarta

I recently added to my Matlab File Exchange function, Perceptually improved colormaps, a colormap for periodic data like azimuth or phase. I am going to briefly showcase it using data from my degree thesis in geology, which I used before, for example in Visualization tips for geoscientists – Matlab. Figure 1, from that post, shows residual gravity anomalies in milligals.

data cube1_final_shading_slope Figure 1

Often we’re interested in characterizing these anomalies by calculating the direction of maximum dip at each point on the surface, and for that direction display the azimuth, or dip azimuth.  I’ve done this for the surface of residual anomalies from Figure 1 and displayed the azimuth in Figure 2. Azimuth from 0 to 360 degrees are color-coded using Jet, Matlab’s standard colormap (until recently). Typically I do not trust azimuth values when the dip is close to zero because it is often contaminated by noise so I would use shading to de-saturate the colors where dip has…

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Color Palettes

21/05/2017

improved rainbow with sawtooth-shaped lightness profile

Source: Color Palettes

The rainbow is dead…long live the rainbow! – series outline

21/05/2017

How to Display Feature Collection GeoJson with Leaflet’s Marker Clusters

20/05/2017

Exploring Spatial

I enjoyed playing with Leaflet’s marker cluster plugin this weekend while writing a new demo, Demo 5, that shows how to load feature collection GeoJson into a Leaflet map layer.

Leaflet Marker ClusterIt was surprisingly easy to setup. First, I updated my GeoJson utility project to create feature collection GeoJson loaded with 768 of my runs from Garmin Connect. The features in the feature collection are summaries. They contain the same properties as the activity detail GeoJson from Demo 4, except that they use starting latitude/longitude instead of a polyline.   Next, I generated individual feature GeoJson files for each run with the full polyline. Finally, I added the new GeoJson files to my website at http://www.exploringspatial.com/activity/.

A Backbone Collection, Activities.js, uses AJAX to fetch the activity summaries. The collection is passed into the ActivitiesMapLayerView.js. The code in its render function is simple:

render: function() { var _self = this; geoJsonLayer = L.geoJson(this.collection.toJSON(),{ onEachFeature: _self.onEachFeature }); this.map.fitBounds(geojson.getBounds())…

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Quick Leaflet with GeoJSON demo

20/05/2017

Nelson's log

I’m exploring Leaflet as an alternative to Polymaps, mostly because Leaflet has some momentum and is faster to render on iOS. here’s a quick demo of drawing a raster map with a GeoJSON overlay.

“track” was preloaded as a JSONP script. ogr2ogr barfs on converting my GPX files from Runkeeper directly to GeoJSON, so I exported them out of PostGIS instead with

Leaflet uses SVG for the GeoJSON layer. Pretty simple structure, svg > g > path, I think one per GPS track.

With just a bit more work it was easy to load 65 walking tracks via Ajax (165k data total) and plot them all in a browser. Performance is pretty good on iOS; the main thing I don’t like is the way the GeoJSON layers disappear during a resize.

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Keep It Simple and Specific

17/05/2017

Source: Keep It Simple and Specific

Bird’s-eye-view reveals priority habitat for threatened shorebirds

16/05/2017

North Atlantic LCC’s Beach and Tidal Habitat Inventories

Source: Bird’s-eye-view reveals priority habitat for threatened shorebirds