mapping tile lines with remote sensing and gis · mapping tile lines with remote sensing and gis...
TRANSCRIPT
Mapping Tile Lines with Remote Sensing and GIS
Jim Giglierano
Iowa DNR
Iowa Geological and Water Survey
How do you map something that by its nature is underground? And
mostly there are no 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
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 County Major rainfall events 4/25 and 4/26/2007 – orthos flown 4/29/2007
Test Area Year 2 – Repeatability Test - Wright County Major rainfall events 4/25 and 4/26/2007 – orthos flown
4/29/2007
Year 3 - Locations of 8 study
areas (based on townships) in the
Prairie Pothole Region of Iowa where aerial
imagery will be collected after
significant rainfall events (>1”) for
mapping buried tile lines.
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.
Year 1 Goal – test >1” rainfall on Greene Co test small plane, camera and gps
First flight to test area under dry conditions
Oblique photo index over Greene County test area
Using Google Earth as a viewer for geotagged oblique photos EasyGPS for extracting GPS track
GPicSync for syncing GPS time/position to camera time
Dry Conditions – some oblique pictures of recently installed tiles
Dry Conditions – some oblique pictures of recently installed tiles
Installing a new main tile for a new drainage district
Tried 7 times – flew only 3 times sick pilot, plane unavailable, too many clouds, drought
Last chance – 6/17/2012
6/15/2012 Nexrad rainfall totals Iowa Environmental Mesonet GIS data
6/15/2012 Nexrad rainfall totals Iowa Environmental Mesonet GIS data
Boone County soybean field
Boone County soybean field Rectified oblique photo – tiles mapped based on drying patterns
Spring 2013 – Greene County and Wright County test areas
• Goal is to develop a regional or statewide business plan for production mapping of tiles
• Two contractors hired for 2013: ASI and Geovantage
• Greene County test area priority 1 • Wright Count test area priority 2 • Targets of opportunity based on weather
cooperating – will the drought continue? • Enough funding for 4-5 test areas total – 20-30 sq
miles each • Use daily Nexrad rainfall total to determine targets
