TagGoogle Earth

Google Maps and Earth is the poor man’s GIS

For over four years, Google’s geography products have become the most popular geographic information systems on the Earth (no, the earth). Google is now as much a platform of GIS for computers and users as ESRI, the number one GIS software maker.

To continue its corporate goal of organizing the world’s information, Google has made sure to also organize the world’s (and other realms) geographic information.

Google’s free tools and products manipulate, map, reproduce and analyze geographic information:

  • Maps – the simplest source of satellite imagery for the public, although Microsoft’s TerraServer was probably first
  • Street View
  • Transit – including travel directions for trips on Transit
  • Ocean
  • Earth desktop software – includes Moon, Mars, Sky
  • My Maps
  • Yellow pages-style business listings
  • Driving and Walking Directions – including automobile traffic overlay
  • Keyhole Markup Language (KML) – a file format based on XML that allows for the easy sharing and portability of data about locations. I wrote about it here.
  • Maps API – this allows developers to include maps in their own applications and websites as well as build features on top of maps

These applications now allow anyone in the world with an internet connection* and a computer to start thinking about the world and neighborhood in which they live in terms of space, distance, the environment, land use, and most important of all the relationships between real life places and these greater themes. But not only will these instruments influence the thinking of individuals and the groups to which they belong, but they will give people tools to create.

What have people created with Google’s GIS tools?

I created a map that shows the locations of open grated metal bridges on bikeways (featured in the bike map) in Chicago. This is important to bicyclists because open grated metal bridges can be hazardous to them, especially those with high centers of gravity or narrow tires on their bikes. Bicyclists will most often encounter these bridges on trips into and out of the Central Business District. This map will help bicyclists find routes that avoid these bridges. Precipitation exacerbates the danger, especially if it’s actively raining, or snow isn’t melting.

UPDATE 12-03-10: I was looking for information on an upcoming Chicago Cyclocross meet and I found a great example of using the tools Google has created for everyone. See a screenshot of the map below:

I’m posting this image to show how easy it is to create a map that tells a story. The story here is a guide on how to be a participant or spectator at the meet. It points out places where people can park, cannot park, and where the restrooms are in relation to parking or the race course. See the full map.

What have you created? Leave a comment below.

Evolution of Google’s GIS toolbox

I believe that Google will continue to expand its array of GIS-related applications, and also expand their existing ones. I would like to see them create new connections between the applications they’ve already created. For example:

  • Google can mimic the attribute table essential in desktop GIS software (like ESRI’s ArcGIS, qGIS, or GRASS) by integrating their Docs web application with My Maps. I want to save my information in a Google Docs spreadsheet (either inputted directly online or uploaded from my computer), then create a custom map and assign a location to each of the records in my spreadsheet. Then, using tools shared between Docs and My Maps, I can automate the creation of colored points and lines for the records based on categories or numbers in my spreadsheet, much like the classification and symbology tools of desktop GIS software. For example, on my “open grated metal bridges” custom map discussed above, I want to create a spreadsheet with a column that has a yes or no value to the question, “Is the bridge treated?” All records with “yes” will have green dots, and all “no” values will have blue dots.
  • The reverse situation could also be made possible by an integration between My Maps and Google Docs. Let’s say I’m a clerk at my church and I need to group the congregants into geographically close clusters for purposes of assigning community service work. I’ve inputted all of their addresses into My Maps and added a point for every house. There’re only 40 houses on the map and I can see see about 5 clusters (to keep it simple I won’t introduce arithmetic means of finding clusters). I use a selection lasso in My Maps and select the points in my first cluster. Using a new Classify function I label these points part of Cluster 1 and color them purple – I also assign Cluster 1 to work at the nearest park. I continue for the remaining four clusters, assigning each cluster to help clean a different park. Once I’ve completed grouping the houses, I tell My Maps to generate for me a spreadsheet that lists the names and phone numbers and clean up time for all the congregants. Now I can quickly call everyone in Cluster 1 and give them their community service assignment which is convenient to where they live.
  • Google should open up its many data layers. Google has many data layers in its table of contents: They recently added real estate data, but they also have the locations of transit stations and bus stops (including timetables and route information), the addresses and phone numbers of businesses (like the Yellow Pages), as well as terrain in some cases and bike trails in others. If the data in these layers were open, map users could perform some basic analysis like counting the number of check cashing businesses within 1 mile for a study of banking behavior in low-income neighborhoods. Or a map users could find the gain in elevation on a bike trail over 4 miles to determine their ride’s difficulty. Another map user could use the transit information to calculate the level of bus service in a neighborhood by counting the number of stops available and the number of buses scheduled.

I’ll have to figure out a way Google can extract revenue from these features if I want to convince Google to produce them, but sometimes the company builds products and features before it figures out how to make money.

The importance of sharing data in KML format

The KML file is an important format in which to share locational data. KML was developed by a company called Keyhole, which Google purchased in 2004, and subsequently released Keyhole’s flagship product: Earth.

A Keyhole Markup Language file is a way to display on a map (particularly a 3D globe of Earth) a collection of points with a defined style. Google has added more functionality and style to the KML format, expanding the styles that can be applied and the information that can be embedded.

KML, like XML (eXtensible Markup Language), is extremely web-friendly. For a web application at work I developed, I included this PHP class that creates an KML file on-demand based on a predefined database query. The file contains locations and attributes of recently installed bike racks in Chicago. EveryBlock imports the file and its information into their location-based service, aggregating many news types around your block.

But a KML file is more important than being the native file for use within Google Earth. It’s an open source text file that can be manipulated by a number of software programs on any computer system on earth (or read on a printed page). It’s not encoded, like shapefiles, so I can read the file with my own mind and understand the data it would present in a compatible map viewer. I see lines of organized syntax describing points and polygons, listing their attributes in plain language.

Have you ever tried to see the “inside” of a shapefile? Only GIS programs can read them for you. KML provides data producers and consumers the opportunities to keep data open, available, and easy to use. We need locational data for our work, and we need tools to help us use it, not hide it.

Converting shapefiles and KML files

Google Earth Pro is a slightly more advanced version than the free edition of the popular satellite imagery application (okay, it does way more, but many people just use that feature). One major additional feature it includes is the ability to import GIS shapefiles and display their features on top of the imagery, including terrain. It’s useful to have your data as KML (Keyhole Markup Language) because KML (or KMZ) is easier to share and Google Earth standard edition is free. But then again, it’s useful to have your KML files as shapefiles because proper GIS software is more powerful at analyzing data. Also, someone might ask you for your data in shapefile format (but they could easily follow these instructions).

Good data management requires options. Options mean your data won’t be locked into a proprietary format. Data want to be free! Read on for ways to convert your KML and shapefile data:

Converting KML files to shapefiles

Like Google Earth Pro, Quantum GIS (QGIS) can convert KML or KMZ to shapefile, and best of all – it doesn’t cost $400 per year (it’s free!). QGIS is a cross-platform application meaning it will run on Windows, Mac OS X, and Linux.

Use QGIS to convert a KML or KMZ file to shapefile:

  1. Click on Layer > Add Vector Layer
  2. Find your KML or KMZ file.
  3. Right-click your new layer and click “Save as shapefile.”

Zonums provides online conversion tools. Or, use ArcGIS and this plugin to convert KML files to shapefiles.

Converting shapefiles to KML files

The freeware Shp2kml 2.o (Windows only) from Zonums will convert shapefiles to KML files. Want some free, interesting data to try it out? Check my ever expanding repository.

ESRI’s ArcGIS can convert KML files to shapefiles using this plugin and then import the shapefile as a layer onto your map.

Creating KML files online

As I described in this post, BatchGecode will generate a KML file for you by inputting a list of addresses and names. Additionally, Google Earth (part of the rising Google GIS platform) creates KML files. Google’s My Maps feature also allows you to generate KML files (for sharing or download) by clicking and drawing points and lines on a map and inviting you to describe the features you create. Use this to get a map of your church congregation, or a map of people who voted for your candidate.

GeoCommons Finder lets you upload geodata in many formats, save it to your profile, and then download it into multiple formats. You can upload a shapefile (.shp) and its accompany files (shx, dbf, and prj), verify that it read your data correctly,

More choices for converting

Additional software with conversion capabilities:

  • MapWindow (another free software choice; Windows only) – An alternative to QuantumGIS and ArcGIS.
  • ExpertGPS (Windows only, not free) – Ideal for GPS device owners, or for researchers using GPS devices in projects. But it can convert the GPS and shapefile data into KML, shapefiles, or a spreadsheet, amongst other functions.
  • Zonums, creator of the standalone Shp2kml software converter, now offers many online tools for KML users, including one that reverses the conversion and exports shapefiles from KML files. I found the link on FreeGeographyTools.com.
  • OpenGeo Suite – Commercial software with non-profit licenses.
  • uDig – Free GIS software, but I haven’t had good experiences with it on my computers.

GeoCommunity has a good article, with screenshots, on how some of these programs work.

Need to work with General Transit Feed Spec (GTFS) data?

GIS and mapping tools

Some of the work I do for school and my job requires that I make maps. I’ve never taken a class on how to make maps or analyze data sets featured in maps (what GIS does), so I learn as I go.

There’s no one around me I can call upon when I have questions that need immediate answers. Well, there’s me! Because of this, I must quickly find a solution or workaround myself.

Today I had to import a list of Chicago Transit Authority and Metra rail stations into ArcGIS so I could plot them on a map that also showed Chicago’s boundary and our bikeways. I could do this in Google Earth, but then I would have less control over the printed map I wanted to make, or the image output. ArcGIS has a built-in geocoder and I learned how to use it six months ago, but a skill not practiced is lost – and I forgot how to do it.

That’s okay – what follows is how I overcame this barrier:

Because I know how to use PHP to instantly create Keyhole Markup Language (KML) files (the format which Google Earth and Maps speaks fluently). Then, with this user-contributed KML to SHP plugin for ArcGIS, I was able to convert my KML files to Shapefiles and display them on my map. Unfortunately, my custom “fancy” icons were lost in the translation. Supposedly this alternate user-contributed script does the same thing.

Other tools I used to get my map created:

  • BatchGeocode.com – This site is indispensable for turning a list of addresses (with names, descriptions, and URLs) into the same list but with latitude and longitude coordinates! It will even create a KML file for you.
  • KML Generator (PHP class) – This class allows you to quickly and easily create KML files from any array and array source of coordinates. I store the transit stations in a database and run a query on the database and loop through them to generate the points in a KML file.

I’d like to thank James Fee’s GIS Blog for the links to the ArcGIS scripts/plugins I used in my project. To everyone else who must confront software, technology and mapping roadblocks, there’s almost always a solution for you.

Read about how I got around QGIS’s lack of geocoding.

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