Tuesday, April 27, 2010

Moving this GIS Blog to a New Geospatial Blog

As of January 1, I am no longer at Vassar College. I started the GIS at Vassar blog for myself, so that I could do my job better, to keep track of links to useful web sites, to remember Google Earth KML network links useful for teaching, to answer questions that faculty and students had around the college, and to remember projects that I found valuable. Over the three and a half years of running this blog (I started it in September 2006), I've had an average of about 50 page views a day. And though I really slowed down on my posting while I've been doing my Fulbright, I still get visitors. So the GIS at Vassar blog and the old posts will stay right where it is, but I will no longer add new posts to it. I will start more posting to a new blog called Geospatial Technologies in Education that I set up on Posterous. I migrated the old posts there but will keep adding new material. Please follow me there.

And if you're in the market for an educational and geospatial technology professional with skills in ArcGIS, Google Earth, field technologies like tablet PCs and GPS receivers, and spatial literacy, I'm available... stewart (dot) meg (at) gmail (dot) com

Wednesday, April 14, 2010

Final Map For Grenadines MarSIS Project: Some of the Details

I have finished up my Google Earth project for the Grenadines. If I didn't have grant proposals, papers, job searches and interviews, and other mundane tasks like that, I would have completed this project in about six weeks. That's the way it goes sometimes.

Here is the link to the Grenadines MarSIS geodata KMZ for your viewing pleasure. The link will launch Google Earth.

I also created (thanks to Valery Hronusov) a KMZ of a nautical chart for the Grenadines. Check it out. It’s big, about 10MB.

And check out the video that describes what’s in the file and explains how to make sense of the many layers of data.

After the first draft of this KMZ, I ran a post that gave a little how-did-I-do-it synopsis. Now I will discuss what the final issues were and how I resolved them.

The original database I was handed was compiled as an ESRI geodatabase. I'll admit it, I have been slow to the geodatabase lifestyle. When I exported shapefiles in my first draft, I had lots of '1's and '2's that looked like this: Island= 1. What I needed to do was export feature classes to a shapefile. I had to switch all the ‘1’s to equal the proper designation that the researcher applied back when the database was built. So now the file shows Island = Mayreau. It was a bear, I must say. But it made it so that the KMZ placemarks contained the information that the original layer contained. It had to be done.

I had to use an HTML editor. I don’t think I mentioned this in my other post, but it is required. That little HTML class I took back in 1996 at the community college still comes in handy. I used HTML-Kit. It is free and works like a charm.

The MarSIS logo used to not stay static. It would stretch and squish when the Google Earth window was resized. I used this helpful site that gave me the code to help me created the screen overlay for the MarSIS logo. This interactive KML code site is superb as it gives you the code to work up in your HTML editor.

I got the snippets, those extra lines of text under the folder or placemark (circled above), to go away. That was done with the HTML editor. Use this snippet code
after the folder or placemark name tag. Find the snippet code discussion here.

I added a legend for the habitats, both shallow water and deep water, using Adobe Illustrator and then creating a screen overlay, see above, with that raster but this time hard-wired to the lower left-hand corner of the screen.

I mentioned in another post that I had fabulous success with SuperOverlay. It bears repeating. I had a large raster file map that I wanted to bring into the project. SuperOverlay was the way to go because it automated the process of slicing up the map to create a smaller KMZ. It was still 10MB so we did not include it with the project KMZ.

Lastly, I had about 200 photographs and 200 videos with geolocations by latitude and longitude to include in the KMZ. Google Spreadsheet Mapper 2.0 made geolocating photos a breeze. Video are a different story. The first draft of the project had a simple screen capture taken from each of the 200 videos that I used as a placeholder until I uploaded each of the videos to a place. That place was YouTube, naturally. The problem is, Spreadsheet Mapper does not take video embed codes, unfortunately. What I did was meticulously copied each video’s embed code as the video finished being uploaded, saved those codes to MS Excel (could have used Google Docs but didn’t), then modified the original previously geolocated placemarks with screen captures that I had created in Spreadsheet Mapper. I erased out the tag for the image and copied in the embed code for the video. It worked very well. All of this was NOT a big deal and I spend more time dreading doing it than I needed to. In retrospect, using the Spreadsheet Mapper to geolocate the video locations was very useful for quickly and accurately finding where the videos belonged in the world.

And now I am done and popping some sparkling wine. On to the next project...organizing the CERMES department's GIS data library. Cheers!

Mashup image above uses a Creative Commons photo from titanium22’s photostream.

Friday, April 09, 2010

Talk on Tablet PCs in Field Classes and Research

I was invited to give a talk this afternoon as part of the CERMES brown bag lecture series. It was nice to show marine-based people the use of a tablet PC, where all of my examples are terrestrial. Their wheels were turning. Here are my slides; I linked to videos during the talk so check those out too.