mapping tile lines with remote sensing and gis jim giglierano formerly with iowa dnr - geological...
TRANSCRIPT
Mapping Tile Lines with Remote Sensing and GIS
Jim GiglieranoFormerly with
Iowa DNR - Geological and Water Survey
Iowa State [email protected]
How do you map something that is by its nature, hidden underground? And
mostly there are no public records indicating their location!
Manually photo- interpreted and digitized GIS coverage of buried tile lines (blue) using 2007 CIR ortho as base map. Green lines are public
drainage district tile lines obtained from county maps.
Color-infrared orthophoto taken in spring of 2007, in Wright County, Iowa, a few days after
3” rain event. Tile lines are indicated by lighter pattern, where soils are draining faster
because of buried tile lines.
Need a 1” or greater rainfall event, wait 2-3 days for soil drainage to begin, drying pattern develops over working tile locations
No crops, springtime best after tillage
Example of recently installed drainage tiles
in Greene County, Iowa. Location of tiles was collected by tile contractor using GPS
during installation and provided by Greene
County drainage clerk’s office.
Some drainage tiles have been captured during installation with GPS
Some tiles are visible just after installation. But you have to get lucky with the image timing to catch these.
EPA funded project to develop a business plan for mapping tiles on a regional or statewide basis
Develop and test remote sensing and GIS procedures for mapping tiles
Test Area Year 1 - drainage districts, tile mains, GPSed tiles from Greene County
Develop and test remote sensing and GIS procedures for mapping tiles
Test Area Year 2 – Repeatability Test - Wright CountyMajor rainfall events 4/25 and 4/26/2007 – orthos flown 4/29/2007
Test Area Year 2 – Repeatability Test - Wright CountyMajor rainfall events 4/25 and 4/26/2007 – orthos flown
4/29/2007
Year 3 - Locations of 8 study areas (in red). These
locations are based on water sampling
projects.
Task 2 - Wetland basins are
identified using 1 meter lidar DEMs and ArcGIS “fill”
command. Subtracting
original DEM from the filled DEM calculates
the depth of the basin (various
colors on map), and turning the filled areas into
polygons creates the wetland basin outline
shape file (purple outline color).
Wetland basins outlines are in blue.
Imagery is from 2007. Numbers
indicate how many years (2004 – 2007)
land cover inside the basin outline is different from land cover surrounding outline. 2007 was “normal” year for moisture levels, so
most basins are cropped
continuously across wetland
boundaries.
Wetland basin outlines in blue, imagery from a very wet year, 2008. Many of
the basins in this photo were too wet to plant any crop. Numbers indicate total
number of years (2004-2008) land cover inside the
basin boundary is different from
land cover outside.
Go to ArcGIS
