February 24
Today we will look at LiDAR data and various ways to respond to a practical request: analysis of the topography of Maumee Bay State Park and the surrounding area. The problem we had last week was due to Web security - you cannot download from an 'active' page (one containing executable code) to our student cluster computers (thank you, Big Brother). EIT tells me that this is a Microsoft feature (now you know who Big Brother really is) so I zipped up all the files and you should download and unzip them before class.
Before class Friday, download and unzip This File. Save the unzipped files to a single folder on your "H" drive or on a Flash drive - and bring it to class.
Additional links to image and Lidar data
We will meet (those of us not in the field) at 10 AM in BO 3051.
1. "Save as" data from each link in a storage area with lots of room - the largest of these files is about 16 megabytes in size.
2. Open ArcView.
3. Add Table. These data files are in text (.txt) format.
4. Open a View. Under View menu, Add event theme. Select the tile to open.
5. With a theme active Convert to Shapefile (under Theme menu). Save the new shapefile in the folder with the rest of your voluminous data.
6. Delete the event theme (why clutter up the page?).
7. Now we can use ArcViews Projection Utility to transform coordinates. These data are probably in State Plane Coordinates (Ohio North) and I think we should work in NAD83 UTM (meters).
Orthophotos: These ARE in NAD83 UTM (meters)
Once we have the LiDAR shapefiles in the same datum we can add them to the view with the orthophotos and begin classification and later, perhaps export the interesting parts to use in Surfer. Before we can export the LiDAR, however, we should add UTM XY values to their shapefile tables.
Select a LiDAR shapefile and 'begin editing". Open the table and delete the east and north coordinate fields (which still list the state plane coordinates). Do this for each LiDAR table.