First, each Landsat image was delineated into regions in an unsupervised classification. Second, each region was assigned a land cover type label in a supervised classification. Regions classified as conifer cover types were also assigned labels for tree size class and canopy cover. A total of 31 land cover type classes, 5 tree size classes, and 5 conifer canopy cover classes were labeled across the three scene area. Accuracies were estimated for the land cover type and tree size classifications of each Landsat image. Third, the regions from all Landsat images were edgematched together into the BLMSILC3Z database. Below is a description of how the original Landsat images were delineated into ground feature regions, how the regions were labeled to land cover type, tree size, and tree canopy, and how the Landsat images were edgematched into one database.
Image SILC Image-Date Covertype-Acc Treesize-Acc SCENEPOLY-ID ------------------------------------------------------------------------------- P40R28 3 7/26/96 72.2% 57.1% 50000001 .. P39R28 3 6/28/94 80.7% 69.6% 52000001 .. P39R29 3 6/28/94 72.1% 54.7% 53000001 .. P40R29 2 7/31/92 62.8% Not Assessed 48000001 ..
Each image was run through an unsupervised classification to classify the approximately 56 million pixels into 130-150 spectral classes. The SILC3 images used a potential natural vegetation (PVT) classification provided by Region One of the USDA Forest Service as a seed source in the unsupervised classification. Using an iterative classification process with spectral signature files and PVT seed, each pixel was assigned to a spectral class. The pixels were then merged into regions (raster polygons) through a multi-stage merge algorithm using a variable minimum map unit based on heterogeneity of the surrounding pixels. Regions larger than 202.4 hectares were divided until all regions in the grid were less than 202.4 hectares (500 acres). The final unsupervised classification resulted in the creation of regions ranging in size from 0.1 hectare to 202.2 hectares. Each region was assigned a set of attributes for TM channels 1-7 and panchromatic from the imagery, along with elevation, aspect, and slope from the 30 meter digital elevation model (DEM); these attribute values were calculated based on the mean values of the 30 meter pixels within each region.
Vegetation overstory (land cover type) was labeled using a supervised classification. The land cover type supervised classification was performed using a combination of manual and training data classifications. The following classes were manually labeled: urban, irrigated and non-irrigated agriculture, recently burned areas, water, mines, snow, and clouds. The other land cover types were labeled using training data and spatial classifiers. The training data were screened for data attribute accuracy, positional accuracy, and agreement with the imagery. The land cover type labels were filled into the COVERTYPE field of each scenes region grid.
COVERTYPE DESCRIPTION ------------------------------------------------ 1100 Urban or Developed Lands 2010 Agricultural - Dry 2020 Agricultural - Irrigated 3130 Very Low Cover Grasslands 3150 Low / Moderate Cover Grasslands 3170 Moderate / High Cover Grasslands 3301 Mountain Mahogany 3380 Low Cover Sagebrush / Xeric Shrublands (15-24% shrubs) 3390 Moderate Cover Sagebrush / Xeric Shrublands (25-34% shrubs) 3395 High Cover Sagebrush / Xeric Shrublands (>= 35% shrubs) 3550 Very Low Cover Sagebrush / Xeric Shrublands (5-14% shrubs/10-24% grass) 3560 Very Low Cover Sagebrush / Xeric Shrublands (5-14% shrubs/>= 25% grass) 3610 Mesic Shrublands 4101 Aspen 4150 Mixed Broadleaf / Cottonwood Forest 4203 Lodgepole Pine 4204 Whitebark Pine 4205 Limber Pine 4206 Ponderosa Pine 4212 Douglas-fir 4214 Rocky Moutain Juniper 4215 Western Larch 4216 Utah Juniper 4223 Douglas-fir/Lodgepole Pine 4230 Douglas-fir/Ponderosa Pine 4237 Subalpine Fir/Spruce 4241 Mixed Upper Subalpine Conifer Forest 4242 Mixed Lower Subalpine Conifer Forest 4244 Mixed Xeric Conifer Forest 4400 Burns 5000 Water 7300 Rock 7500 Mines/Quarries 9100 Snow 9800 Cloud 9900 Cloud Shadow
Conifer tree size and canopy cover labels were assigned using a training data classification. The training data were screened for data attribute accuracy, positional accuracy, and agreement with the imagery. Due to a high level of disagreement between the training data tree canopy call (see accuracy assessment), and the imagery, the tree canopy data was recoded based on MNDVI splits. The tree size labels were filled into the TREESIZE field and the tree canopy cover labels were filled into the TREECANOPY field of each scenes region grid.
TREESIZE DESCRIPTION ------------------------------------- 1 Sapling 1.0-4.9" DBH 2 Pole 5.0-8.9" DBH 3 Medium 9.0-14.9" DBH 4 Large 15.0-20.9" DBH 5 Very Large 21.0-99.0" DBH
TREECANOPY DESCRIPTION ------------------------------------- 1 1-9% Cover 2 10-24% Cover 3 25-44% Cover 4 45-64% Cover 5 65-100% Cover
A cross validation (leave-one-out), accuracy assessment for land cover type and tree size of each scene was performed using the entire training data set. No estimate of accuracy was performed on the manually classified land cover types.
Edgematching was done by selecting regions from only one of the scenes in overlap areas. First, the imagery was visually analyzed to select cloud free or snow free areas in overlap zones. Next, the images were ranked based on overall image quality. Finally, after the land cover type classification, regions were selected that created a consistant covertype pattern across the transition zone from one scene to another. The end result was a region grid with 4,820,703 regions.
Image Landsat SILC Date Priority Number of Regions Used ------------------------------------------------------------- P40R28 5 3 07/26/96 1 229,193 P39R28 5 3 06/28/94 2 87,378 P39R29 5 3 06/28/94 3 241,569 P40R29 5 2 07/31/92 4 18,796 ------------------------------------------------------------- Total Regions in Database 576,936
To help track similarities and differences in map legends between this classification and previous ones (SILC1 and MT-GAP) cover type names and codes numbers were not changed if the actual types were mapped using similar training data. Please see the individual scene report documents for further details.
Users accuracies of land cover types were:COVERTYPE P40R28 P39R28 P39R29 P40R29 ------------------------------------- 3130 81.9 83.2 82.0 69.6 3150 88.7 80.9 92.1 85.6 3170 78.6 81.0 82.7 74.4 3301 84.0 75.7 NA NA 3380 40.2 38.8 38.2 41.0 3390 28.7 71.6 38.9 30.7 3395 48.3 36.8 48.7 31.2 3550 48.3 44.1 48.7 37.5 3560 33.3 33.3 17.6 28.6 3610 75.2 80.7 63.0 64.5 4101 81.0 79.2 75.8 73.1 4150 80.0 86.0 97.3 99.9 4203 76.2 78.8 75.1 84.8 4204 73.6 92.5 87.5 76.9 4205 NA 70.8 NA NA 4206 79.1 71.4 NA NA 4212 79.7 93.7 87.4 90.7 4214 NA 72.4 NA NA 4223 61.0 79.5 16.7 NA 4230 63.6 79.2 NA NA 4237 58.9 61.9 55.9 NA 4240 55.8 77.6 53.3 25.0 7300 99.2 99.4 98.4 99.9 ------------------------------------- Overall 72.2 80.7 72.1 62.8
Users accuracies of conifer tree size classes were:
TREESIZE P40R28 P39R28 P39R29 P40R29 ------------------------------------------------------------------------ 1 Sapling 46.3 17.9 47.1 NA 2 Pole 60.6 82.3 54.2 NA 3 Medium 65.1 79.1 60.1 NA 4 Large 51.1 25.7 23.5 NA 5 VLarge 13.8 12.1 28.6 NA ------------------------------------------------------------------------ Overall 57.1 69.6 54.7 NA
MAKE_DEM: extracted a digital elevation model (DEM) from the WSAL database for use during labeling.
MAKE_HYDROGRAPHY: extracted a hydrography coverage from the WSAL hydrography database for use during labeling.
BUILD_VAT: built an ArcInfo value attribute table (VAT) to hold all items (fields) for which descriptive data could be developed for each region. Filled in VALUE, COUNT, LINK, HECTARES, PERIMETER, TM1, TM2, TM3, TM4, TM5, TM6, TM7, PAN, TM1STD, TM2STD, TM3STD, TM4STD, TM5STD, TM6STD, TM7STD, PANSTD, MNDVI, ELE, SLP, ASP, and SLPASP fields.
The Mixed Conifer type 4240 was recoded to 3 types using an aml based on the PVTCODE and ELEVATION for the region. The 3 types are:
4241 Mixed Upper Subalpine Conifer Forest 4242 Mixed Lower Subalpine Conifer Forest 4244 Mixed Xeric Conifer Forest
1 very low cover 0-9% MNDVI < 10 2 low cover 10-24% MNDVI >= 10 and MNDVI < 50 3 low/mod cover 24-44% MNDVI >= 50 and MNDVI < 85 4 mod/high cover 44-64% MNDVI >= 85 and MNDVI < 125 5 high cover 64-100% MNDVI >= 125
CREATE CAN-SIZE CODE: A combined conifer canopy/sizeclass code was developed by multiplying the conifer canopy code by 100 and then adding the conifer sizeclass code. Thus for a plot with conifer canopy 2 (low cover - from above recode) and conifer sizeclass 3 (medium) the combined code would be:
(2 * 100) + 3 = 203
A total of 25 different conifer canopy/sizeclass codes were developed.
3301 Mountain Mahogany 3380 Low Cover Sagebrush / Xeric Shrublands (15-24% shrubs) 3390 Moderate Cover Sagebrush / Xeric Shrublands (25-34% shrubs) 3395 High Cover Sagebrush / Xeric Shrublands (>= 35% shrubs) 3550 Very Low Cover Sagebrush / Xeric Shrublands (5-14% shrubs/10-24% grass) 3560 Very Low Cover Sagebrush / Xeric Shrublands (5-14% shrubs/>= 25% grass)
Training data and spatial classifiers were used to classify land cover types. Land cover types were classified using variables: TM1, TM2, TM3, TM4, TM5, TM7, MNDVI, ELEV (scaled elevation ELE / 25), SLP, and SLPASP; a Dudani distance-weighted classifier with a nearest neighborhood size of 10-15, and a mid inverser distance spatial classifer. The results of the classification were filled into the COV_CODE_1, COV_CODE_2, and COV_CODE_3 fields. The final land cover type label was filled into the COVERTYPE field from the MANLABEL field if it was > -1 or from the COV_CODE_1 field.
The Mixed Conifer type 4240 was recoded to 3 types using an aml based on the PVTCODE and ELEVATION for the region. The 3 types are:
4241 Mixed Upper Subalpine Conifer Forest 4242 Mixed Lower Subalpine Conifer Forest 4244 Mixed Xeric Conifer Forest
SCENE RANGE
------------------------------
P40R28 50408045 - 50767022
P39R28 52402964 - 52729600
P39R29 53040844 - 53473612
P40E29 48057437 - 48249136
COVERTYPE DESCRIPTION ------------------------------------------------ 1100 Urban or Developed Lands 2010 Agricultural - Dry 2020 Agricultural - Irrigated 3130 Very Low Cover Grasslands 3150 Low / Moderate Cover Grasslands 3170 Moderate / High Cover Grasslands 3301 Mountain Mahogany 3380 Low Cover Sagebrush / Xeric Shrublands (15-24% shrubs) 3390 Moderate Cover Sagebrush / Xeric Shrublands (25-34% shrubs) 3395 High Cover Sagebrush / Xeric Shrublands (>= 35% shrubs) 3550 Very Low Cover Sagebrush / Xeric Shrublands (5-14% shrubs/10-24% grass) 3560 Very Low Cover Sagebrush / Xeric Shrublands (5-14% shrubs/>= 25% grass) 3610 Mesic Shrublands 4101 Aspen 4150 Mixed Broadleaf / Cottonwood Forest 4203 Lodgepole Pine 4204 Whitebark Pine 4205 Limber Pine 4206 Ponderosa Pine 4212 Douglas-fir 4214 Rocky Moutain Juniper 4215 Western Larch 4216 Utah Juniper 4223 Douglas-fir/Lodgepole Pine 4230 Douglas-fir/Ponderosa Pine 4237 Subalpine Fir/Spruce 4241 Mixed Upper Subalpine Conifer Forest 4242 Mixed Lower Subalpine Conifer Forest 4244 Mixed Xeric Conifer Forest 4400 Burns 5000 Water 7300 Rock 7500 Mines/Quarries 9100 Snow 9800 Cloud 9900 Cloud Shadow
TREESIZE DESCRIPTION ------------------------------------- -1 NOT CONIFER 1 Sapling 1.0-4.9" DBH 2 Pole 5.0-8.9" DBH 3 Medium 9.0-14.9" DBH 4 Large 15.0-20.9" DBH 5 Very Large 21.0-99.0" DBH
TREECANOPY DESCRIPTION ------------------------------------- -1 NOT CONIFER 1 1-9% Cover 2 10-24% Cover 3 25-44% Cover 4 45-64% Cover 5 65-100% Cover
ASP Description -------------------- 0 Flat 1 North 2 Northeast 3 East 4 Southeast 5 South 6 Southwest 7 West 8 Northwest
COV_CODE_1 DESCRIPTION ------------------------------------------------ 3130 Very Low Cover Grasslands 3150 Low / Moderate Cover Grasslands 3170 Moderate / High Cover Grasslands 3301 Mountain Mahogany 3380 Low Cover Sagebrush / Xeric Shrublands (15-24% shrubs) 3390 Moderate Cover Sagebrush / Xeric Shrublands (25-34% shrubs) 3395 High Cover Sagebrush / Xeric Shrublands (>= 35% shrubs) 3550 Very Low Cover Sagebrush / Xeric Shrublands (5-14% shrubs/10-24% grass) 3560 Very Low Cover Sagebrush / Xeric Shrublands (5-14% shrubs/>= 25% grass) 3610 Mesic Shrublands 4101 Aspen 4150 Mixed Broadleaf / Cottonwood Forest 4203 Lodgepole Pine 4204 Whitebark Pine 4205 Limber Pine 4206 Ponderosa Pine 4212 Douglas-fir 4214 Rocky Moutain Juniper 4223 Douglas-fir/Lodgepole Pine 4230 Douglas-fir/Ponderosa Pine 4237 Subalpine Fir/Spruce 4241 Mixed Upper Subalpine Conifer Forest 4242 Mixed Lower Subalpine Conifer Forest 4244 Mixed Xeric Conifer Forest 7300 Rock
MANLABEL DESCRIPTION -------------------------------- 1100 Urban or Developed Lands 2010 Agricultural - Dry 2020 Agricultural - Irrigated 4400 Burns 5000 Water 7500 Mines/Quarries 9100 Snow 9800 Cloud 9900 Cloud Shadow
TREESIZE DESCRIPTION ------------------------------------- 1 Sapling 1.0-4.9" DBH 2 Pole 5.0-8.9" DBH 3 Medium 9.0-14.9" DBH 4 Large 15.0-20.9" DBH 5 Very Large 21.0-99.0" DBH
TREECANOPY DESCRIPTION ------------------------------------- 1 1-9% Cover 2 10-24% Cover 3 25-44% Cover 4 45-64% Cover 5 65-100% Cover