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Archive Page 2 of 106

Real-Time Crowdsourced Mapping With Crowdmap

I first heard about the crowdmapping platform Ushahidi a few years ago; it’s an open-source app/platform that can collect/collate geotagged data in real-time from mobile observers, or delayed reports over the web. The data can then be mapped, viewed on a timeline, and analyzed. One significant obstacle to using the platform was the need to install it on a webserver with PHP/MySQL support – easy for some, but a challenge for others. I’m a bit late (about a year), but I just found out that Ushahidi has created a free service called Crowdmap that hosts the platform for you, lowering the technical barrier significantly. Examples of Crowdmaps include one for the English papal visit, and a Crowdmap for the Australian floods earlier this year (screenshots below).


The map above shows all Crowdmap reports in all categories, plotted by location; clicking on a red dot brings up the option to show more detailed reports for that region.


You can set up report categories, and clicking on a category will show reports for only that category. You can also filter by time and other parameters.


Timelines can be displayed showing the number of reports in any/all categories, like the plot of electricity disruptions above.

Data can be submitted a number of ways:

  • SMS text messages (geotagged)
  • Twitter (geotagged)
  • RSS feeds
  • Web forms
  • Mobile apps for both iOS and Android

As the Crowdmap site points out, while originally designed to provide real-time data tracking, there’s nothing to stop you from using this as a generic crowdmapping app.

There are still reasons why you might prefer to use the Ushahidi platform directly on your own webserver. Doing so gives you more control over the data, and how it will be used.  Ushahidi is developing a complementary open-source platform called Swift River that can filter, verify and analyze real-time data to make more sense of it, and I don’t believe that’s currently available on Crowdmap (though Crowdmap does have some basic analytical tools). I suspect that at least some aspects of Swift River will be integrated into Crowdmap in the future. Even without these advanced Swift River data tools, though, the ease of Crowdmap’s implementation makes it a good choice for many.

National Geodetic Survey Online Toolkit

The National Geodetic Survey has a set of links online conversion utilities for performing some basic geodetic conversions, including:

  • High-accuracy state plane coordinate system (SPCS) conversions
  • UTM/USNG/geographic coordinate conversions
  • Magnetic declination
  • Surface gravity prediction
  • Azimuth/distance to a second position (or second position from azimuth/distance data)
  • Position from a dual-frequency GPS data file

Plus many more. Some of these are also available as PC programs, but these tend to be old-school DOS-based conversion utilities, not always the most user friendly.

Convert A Shapefile Into A Google Fusion Table

Google Fusion Tables is a free service from Google that lets you visualize, map, analyze and combine data. Standard data formats for import are spreadsheet data (including direct export from Google Docs), CSV and KML files. But you can use the Shape to Fusion website to convert shapefile data directly into Fusion Table format, including not just points but also lines and areas. Note: You will need to have a Google account, and will also need to give the Shape to Fusion website permission to access your Google account to upload the data.

The first thing you’ll need to do is prepare a zipped file for upload that contains the .shp, .shx and .dbf files associated with the shapefile; you’ll also need to include a .prj file that specifies the coordinate system used by the shapefile. You’re limited to 200 MB in total uploaded data, and a maximum of 200,000 rows of data. For line and area shapefiles, you have the option of simplifying the geometry to reduce the total row count; you can also create a centroid point for areas.

Depending on the size of the file, it can take a while to process; this sample file of mines in Arizona with 10,512 rows took about 10 minutes. A regularly-refreshed text page will show you the status:


Once completed, you can directly access the Fusion Table data through the link at the bottom, or go to your Fusion Table data list and select the dataset; you can then analyze/visualize the data any way you choose, including maps. If you specify the data as public, you can embed it into a website. Here’s the active embedded map of Arizona mines used as sample data above; click on a point to get a pop-up with the name and products of the mine:

Note: Doesn’t seem to display properly in my copy of Internet Explorer 9; works fine in Chrome and Firefox.

Data can also be exported back out again in spreadsheet format, as a static KML file, or as a dynamic KML link that updates if the data changes.

Note: The source code for this app is available at this Google Code page.

GeoCommons Goes Into High Gear

Posted late last year about GeoCommons, a free service for uploading and displaying free publicly-accessible geographic data. Run by GeoIQ (formerly FortiusOne), this is the free public version of their commercial GeoIQ geographic data visualization service. If you haven’t been following their recent posts on their blog, you may have missed the huge number of new features they’ve added to GeoCommons and GeoIQ over the past six months:

Now they’ve just added a number of GIS-like analytical tools, already in their commercial GeoIQ product, to the free GeoCommons tool:

I’ve only played with this a bit, but it looks pretty damn cool; definitely crosses the border between neogeography tools and GIS. The free version is definitely worth a spin if your data can be freely distributed; if not, still worth a look as an example of what their paid/private GeoIQ service can do.

Free Books From The National Academies Press

SlashGeo posts on the June 2nd announcement by National Academies Press that all their PDF book titles are now freely available for download, or for online reading. National Academies Press is the publishing arm of the National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council. A search using geography-related terms (e.g. GIS, GPS, geography, maps, cartography, etc.) will bring up long lists of titles. They’re a bit of a mixed bag, though – most of them are more along the lines of committee reports, executive summaries, available resources and project planning than they are of more practical applications. Still, worth a look, especially at the price ;-). For many of them, you can also buy hard copies, and even embed a widget for them onto your website to allow people direct access to the book.

Here’s a few potentially interesting titles I picked out with random searching (assuming WordPress doesn’t trash the embed code, the way it sometimes does):

On The Road Again

Back in the field for the next few weeks; posting should resume after Memorial Day.

Free Marine Chart Views, Plus An Online Waypoint/Route Editor With GPS Export

The Marine GeoGarage site offers free online views of marine charts from the following countries:

  • USA
  • Bahamas
  • Argentina
  • Brazil
  • Netherlands

A  10-euro monthly subscription (free 14-day trial) gets rid of the ads, and adds charts for the following countries:

  • UK and vicinity
  • Canada
  • Australia

Choose the country from the list at upper-right:


The slider controls the transparency of the marine chart overlay in Google Maps; slide it all the way to the right, and the map disappears completely (more on this shortly). Map detail level scales with the zoom, so if you start zoomed out:


And then zoom in :


Map detail scales accordingly, if maps are available at different scales.

There are three checkboxes in the control section:

  • photos – shows geotagged panoramio photos. There’s usually so many of them near coastal areas that this feature is pretty useless.
  • fullscreen – Blows up the map interface to full size (but doesn’t get rid of ads in the free version).
  • coverage – Shows the coverage areas for all marine charts available at different scales, useful for seeing whether you can zoom in for more information:



There’s a scalebar at lower left, with the option to set the distance units used, and view the cursor coordinates (though the latter is a bit slow to update):


So far, useful mainly for mariners. But the site also has editing tools that let you create GPS waypoints and routes; while these are useful for marine navigators, setting the map transparency to 100% lets you create terrestrial GPS waypoints and routes anywhere in the world. For example, by using the waypoints and routes toolbar:


Plus setting the marine charts invisible, and setting Google Maps to Terrain view, I can create/edit waypoints and routes:


And then export them to a GPX file for use on my GPS:


If you own a Garmin GPS unit, and you have the free Garmin Communicator plugin installed on your browser, you can even export the data directly from the website to a connected Garmin GPS.  Logging in with either free registration, OpenID, Google login, or other credentials, lets you save this data online for future editing and use.

Generate Custom Color Code For Google Maps

The Google Maps Colorizr website lets you set alternate colors for various features in Google Maps, preview the results, and then generate the Javascript code to implement that color change on your own maps.

Start out with the original colors:


At left, you can add feature/color sets with the “+” button, select from all the features types using a dropdown menu, choose geometry/label/both, and then specify the color (RGB hex code, e.g. ff0000 is full red, ff00ff is magenta):


Color changes are updated on-the-fly in the map view:


And at right, the code that will create these changes on your site is displayed in a text box; just copy and paste it into your code:


Nineteen feature types are currently included in the dropdown. Source code for the site is available at github, so you can create your own custom version of the site if you like. A neat little tool to make your own Google Maps more distinctive and unique.