Sunday, September 23, 2007

Coast Guard Site Selection & ModelBuilder

I am teaching the spatial analysis course this semester, and the first two projects everyone is working on is based on a suitability site selection exercise. First, they need to identify the best locations for the development of a new Coast Guard facility on the Gulf Coast. Second, they need to develop an ArcMap Model to automate this suitability process.

Here is their exercise scenario (fictitious, of course) :
The U.S. Coast Guard is concerned about the possible damage to the environment and natural habitat along the Texas Gulf Coast if an offshore oil spill were to occur. The Coast Guard has obtained funds to build a new facility whose primary purpose is to protect the environment.
They are required to use at least one Census 2000 attribute by tract, and whichever data sources they deem necessary from the Texas General Land Office. There are some great Gulf Coast environmental and habitat resources at the GLO, including the Environmental Sensitivity Index Shoreline, In-Situ Burn Exclusion Areas, Offshore Oil/Gas Platforms, Priority Protected Habitat Areas, Wildlife Refuges, and much more. For our educational purposes, it is nice that some of the GLO's files, such as the TXDOT Roads/Highways, are undefined shapefiles to give everyone the challenge of defining it.

After the initial suitability site selection project, everyone will create an automated Model using ArcMap's ModelBuilder. Standard suitability analysis such as this is so straight forward that it works well in Models. However, I found a bug in the latest ArcGIS 9.2 SP3 service pack. Seems as if the Classify button is grayed out when the Reclassify tool is incorporated into a Model. Of course this only occurs when the reclassification scheme is a parameter. I never saw this before and can only assume this is the result of this latest service pack, which was released in August. Searched the user forums, but surprisingly could not find anyone else who come across this problem. I found a work-around, however, which has thus far worked well enough for me not to really complain about this. Found that if you also add the reclassification field as a parameter, then the Classify button become activated. Seems as if the Model is not accepting the reclassification field as specified by the developer, and is requiring the user to specify the reclass field. Good enough. Perhaps this is a new safeguard feature and not a bug.

With that said, their presentations for their initial possible site selections are next week. We've got some great students this semester and I am really looking forward to seeing what they came up with.

3 comments:

sephi said...

Hi
you may want to try and use the geoprocessing layer - it may be a way around the classification and reclassify issue.

mapz said...

Hey thanks for the tip! Soon as I gat back to the office I'll give that a shot.

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