Spatial Analyst - Identify Swimming Pools

[HeatherShearer]

I have a georeferenced raster aerial photo dataset (ecw) overlaid by a vector shape file. I want to identify all properties in the shapefile that have swimming pools (which can be clearly seen on the raster - I could do it manually, but there are 300K plus properties!) I'm sure this is easy, but I don't know Spatial Analyst at all. Any help or links to (simple) tutorials would be greatly appreciated!!!

[ToreBorvik]

One of several approaches: Split the probably 3-band raster into individual bands. Identify the range of pixel values that is typical for swimming pools in each band of the raster. then in raster calculator, make a new 1-band raster that includes the pixel range for each of the input bands (calculation could look like [layer1] > 85 & [layer2] < 205 etc)  Now if you are lucky you have the pools in this raster but probably also some small areas that are not pools. clean up the raster with appropriate tools to get rid of these. At last, convert raster to polygon.


if you have ENVI it is much easier to do it.

[StefanHaglund]

Well, you have some basic remote sensing tools in ArcGIS as well, they're just not that much talked about. Have a look at the Multivariate tools in Spatial Analyst (http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=An_overview_of_the_Multivariate_tools ).

Depending on your imagery it sounds like it should be a fairly simple task to catch the pools using these tools. Like Tore said, you will most likely need to do some clean-up afterwards to get rid of other water surfaces.

If you're on the beta program for 10, these tools have been package in the "Image analysis toolbar", or something similar.