Rapid Land Use and Land Cover Database Development

Transcription

1 Rapid Land Use and Land Cover Database Development

2 Utility of the Land Use and Land Cover Database Socio-Economic Climate Change Water Quantity Water Quality 2

3 Overview of the Mapping Approach Goal: Develop a LULC time-series database for years Produce crop type LULC data for years 2000, Utilize existing crop type LULC data for years 2001, 2005, Create value-added products from crop type LULC data Produce field level LULC representation (2001, completed) Map Irrigation Status (methodology developed; running pilot on 2005 data) 3

4 Filling Gaps in LULC Time Series (2000, ) A Hybrid Hierarchical Classification 1. Produce a general LULC map (Level I) using multi-seasonal Landsat TM imagery and an unsupervised classification (ISODATA) approach 2. Produce crop type map (Level II) using annual MODIS NDVI time-series imagery and a supervised classification approach (Decision Tree) Farm Market ID data used for image classification training and validation 4

5 1. Produce General Land Cover Maps Image Acquisition & Processing Image Classification Two Stage Generalization Multitemporal Landsat TM data Woodland Water Urban Grass/Crop Using MMUs Using CLUs Mosaic Maps Accuracy Assessment 5

6 Status of General LULC for 2002/2003 6

7 2. Produce Crop Type Maps Using a Decision Tree Classifier Extract Cropland Pixels from MODIS Imagery Supervised Classification 80/20% data split for model training & validation Independent sample used for formal accuracy assessment Process Training Data From Farm Market ID Reassign Crop Pixels to Crop Subclasses Accuracy Assessment Wardlow & Egbert, 2008 Resample & Generalization

8 Dominant Crop Types Average multi-temporal NDVI profiles for Kansas NDVI Jan. 1 Jan. 17 Feb. 2 Feb. 18 March 6 March 22 April 7 April 23 May 9 May 25 June 10 June 26 July 12 July 28 August 13 August 29 Sept. 14 Sept. 30 Oct. 16 Nov. 1 Nov. 17 Dec. 3 Dec. 19 Alfalfa Fallow Summer Crops Winter Wheat 8

9 Overview of Existing LULC Data In-house LULC: 2001 & 2005 derived from MODIS & TM imagery USDA NASS Cropland Data Layer (CDL): and ongoing Consistent, replicable methodology allows for inter-annual comparisons 9

10 Limitations of the Cropland Data Layer Noise in the data NASS does not generalize or smooth the data to remove speckling affects Cumulatively, the speckling produces misleading information of proportions of LULC or LULC change 10

11 Value Added LULC: Field Level Representation Original 2007 Cropland Data Layer 2007 Field Level Representation Stafford County 2001, completed, but models can be ran using newly acquired 2008 field boundaries from Farm Market ID. 11

12 Limitations of Existing LULC Data Irrigation Status Not Mapped NASS reports irrigation acreages at the county-level in tabular form Spatial representation provides opportunities for multi-scale analysis

13 Mapping Irrigation Status For each crop type, for each county: Use USDA NASS reported acreages to restrict the spatial extent mapped as irrigated Use Maximum NDVI over the growing season to identify irrigated cropland Use buffers around points of diversion and irrigation canals to restrict locations of irrigated lands 13

14 NDVI Jan. 1 Jan. 17 Feb. 2 Feb. 18 March 6 March 22 April 7 April 23 May 9 May 25 June 10 June 26 July 12 July 28 August 13 August 29 Sept. 14 Sept. 30 Oct. 16 Nov. 1 Nov. 17 Dec. 3 Dec. 19 Corn (Irrigated) Corn (Non-Irrigated) Winter Wheat (Irrigated) Winter Wheat (Non-Irrigated) 14

15 Example: Subset of Republic County Extract Points of Diversion and Canals Used for Irrigation Buffer Points of Diversion and Canals by 1000m 15

16 Extract Cropland Intersecting Buffer Extract peak NDVI Resample to 30-meter 16

17 Extract Corn From Cropland Map Calculate Mean Maximum NDVI for Corn Each Field 17

18 Identify Peak NDVI Thresholds Matching Reported Acreage County Reported Irrigated Corn * zmmx NDVI 240 zmmx NDVI 220 zmmx NDVI 201 zmmx NDVI , ,436 29,790 31,800 Apply NDVI Threshold To Create Irrigated Corn 18

19 Upcoming Year Finalize and apply methodology for mapping irrigation status Complete 2002/2003 General LULC Map Map Crop Types for years 2000,