Additional Assessment of Classified Image

By Glenn H Lawson, USDA/NRCS/NRI&AI

Additional Assessment results of classified TM image using NRI points as ground truth. In addition to the imagery accuracy assessment provided in the image processing software the final classified image was evaluated using photographic interruptions of aerial photography and digital ortho of the same date, 1992.

The final image had 10 classes of cover/use for 1992. They were out of scene, artificial/barren, tree, grass, water, cloud, barren, corn, and soybean.

The final digital layer was merged with a raster form (30X30 meters) of the tiger roads.

It was expected that a certain percentage of the first group would not match the classified image due to the problems of the NRI point data and raster image data earlier discussed. Other evaluations were completed for NRI points that did not exactly meet the map categories and map areas where the NRI was not used as signatures in classification. Some of these results using the group 1 file on the classified image were as follows.

Map values where NRI point was classified as Class 1 (NRI codes 001 thru 006)
1 corn
1 grass

Map values where NRI point was classified as Class 4 (NRI codes 142 & 212)
179 grass
25 tree
108 crop
18 artificial
1 water

This is encouraging as most of the legumes was in the grass map areas and the next highest was in cropland which would be expected.

Map values where NRI point was classified as Class 5 (NRI codes 143 & 213)
706 grass
156 tree
202 crop
63 artificial
2 water

This is encouraging as most of the grass/legume mixture was in the grass map areas and the next highest was in cropland.

Map values where NRI point was classified as Class 6 (NRI codes 111 thru 116)
127 grass
213 crop
15 tree
11 artificial

This is very encouraging as most small grain points were in cropland with the next highest being in grass.

Map values where NRI point was classified as Class 7 (NRI codes 700 & 730)
256 artificial
45 crop
39 tree
106 grass
3 water

This is encouraging as most of the urban coded points were in the artificial map class. The next highest occurrence was in map class grass, then crop and trees. In Iowa the urban areas are located in areas that have a high percentage of grass cover. There is much cropland, therefore this explains why the crop points were present due to small urban areas and large homesteads being surrounded by various crops.

Map values where NRI point was classified as Class 8 (NRI codes 810 thru 830)
178 artificial
116 crop
78 grass
19 tree

This is encouraging as most of these rural transportation coded points were in the artificial map class. The next highest occurrence was in map class crop, then grass and trees. In much of Iowa the roads and urban areas are located in areas that have a high percentage of crop cover. There is much grass cover next to roads. Therefore, this explains why the rural transportation points were present in the crop and grass map areas.

Map values where NRI point was classified as Class 9 ( NRI code 901, 912 thru 924)
109 water
10 grass
19 tree
5 crop
8 artificial

This is encouraging as most of the water points were in map areas classified as water. In many areas water is bound by trees and grasses, which were the next in occurrence. Several times water bodies will vary in size and leave much grass and tree cover.

Map values where NRI point was classified as Class 12 (NRI code 012)
3 crop
2 grass
1 artificial

This is encouraging as one would hope the majority of the grain sorghum points would be in cropland areas but there was so little of this cover and sampling for this cover in Iowa it was impossible to separate this into a separate category.

Map values where NRI point was classified as Class 19 (NRI codes 019 thru 021)
7 crop
2 grass

This is encouraging as one would hope the majority of these crop land points would be in cropland areas but there was so little of this cover and sampling for this cover in Iowa it was impossible to separate this into a separate category.

Map values where NRI point was classified as Class 20 (NRI codes 170 & 180)
18 tree
36 grass
135 crop
10 artificial

This is encouraging as one would hope the majority of points would be in cropland areas but there was so much variation, amount and sampling for this cover in Iowa it was impossible to separate this into a separate category.

Map values where NRI point was classified as Class 22 (NRI code 400)
123 crop
53 tree
122 grass
97 artificial

This is encouraging as one would hope the majority of the farmstead points would be in cropland areas but there was so much association of cropland and grass with farmsteads. However, because of the variation within this class and the sampling technique for this cover it is impossible to separate this into a separate category.

Map values where NRI point was classified as Class 23 (NRI code 401)
2 grass
1 tree
2 crop
1 artificial

This is encouraging as one would hope these points would be fairly even in occurrence with all the map classes. However, because of the variation within this class and the sampling technique for this cover it is impossible to separate this into a separate category.

Map values where NRI point was classified as Class 24 (NRI code 410)
1116 grass
128 tree
115 crop
41 artificial

This is encouraging as most of the CRP program land in IOWA is planted in grass. The remainder can easily be explained as some of he CRP land may not be established or because of a very close association of the location of CRP program land with land still in crop or having tree cover.

Map values where NRI point was classified as Class 25 (NRI codes 611 thru 630)
11 artificial
5 water
6 tree
3 grass

This is encouraging as one would hope the majority of the barren land points would be in artificial cover areas and the remainder be a fairly even occurrence of the other map classes. Because of the variation within this class and the sampling technique for this cover it is impossible to separate this into a separate category.

Map values where NRI point was classified as Class 26 (NRI code 640)
7 tree
7 grass
8 crop
1 water

This is expected as one would hope the majority of the marshland and other rural land points would be a fairly even occurrence of the major map classes. Because of the variation within this class and the sampling technique for this cover it is impossible to separate this into a separate category.

Some of the results using the group 2 file on the classified image were as follows.

Class 4 (landuse92 = 142 or landuse92 = 212 grass herbaceous > 90)
116 grass
10 tree
54 crop
5 artificial

This is encouraging as most of the legumes was in the grass map areas and the next highest was in cropland which would be expected.

Class 5 (landuse92 = 143 or landuse92 = 213 grass herbaceous > 90)
384 grass
41 tree
92 crop
14 artificial
2 water

This is encouraging as most of the grass/legumes mixture was in the grass map areas and the next highest was in cropland which would be expected.

Class 6 (landuse92 >= 110 and landuse92 <= 118 crop close grown > 90 secondary crop = 000
76 grass
7 tree
113 crop
3 artificial

This is very encouraging as most small grain points were in cropland with the next highest being in grass.

Class 7 (landuse92 = 700 or landuse92 = 730 artificial > 70)
7 grass
2 tree
3 crop
74 artificial

This is extremely encouraging as a very high percentage of the urban coded points were in the artificial map class. The next highest occurrence was in map class grass, then crop and trees. The urban areas in Iowa areas are located in areas that have grass, tree, and crop cover.

Class 8 (landuse92 >= 800 and landuse92 <= 845 artificial > 70)
1 grass
1 crop
6 artificial

This is extremely encouraging as most of these rural transportation coded points were in the artificial map class. The next highest occurrence was in map class crop and grass. In much of Iowa the roads and urban areas are located in areas that have a high percentage of crop, grass, and tree cover. Therefore, this explains why some of the rural transportation points were present in the crop and grass map areas.

Class 9 (landuse92 = 901 or landuse92 >= 912 and landuse92 <= 925 water > 70)
83 water
1 grass
2 tree
1 crop
4 artificial

This is extremely encouraging as most of the water points were in map areas classified as water. The remaining points were in the land cover they would be expected.

Class 12 (landuse92 = 012 crop row > 90)
3 crop
1 grass
1 artificial

This is encouraging as one would hope the majority of the grain sorghum points would be in cropland areas but there was so little of this cover and sampling for this cover in Iowa it was impossible to separate this into a separate category.

Class 19 (landuse92 = 019 or landuse92 = 020 or landuse92 = 021 crop > 90)
4 crop

This is extremely encouraging as all of these crop land points were in cropland areas. However, there was so little of this cover and sampling for this cover in Iowa it was impossible to separate this into a separate category.

Class 20 (landuse92 = 170 or landuse92 = 180 crop > 90)
77 crop
13 grass
4 tree
1 artificial

This is extremely encouraging as the majority of points were in cropland areas. However, there was so much variation, amount and sampling for this cover in Iowa it was impossible to separate this into a separate category.

Class 22 (landuse92 = 400 art > 90)
3 grass
1 tree
3 crop
4 artificial

This is expected as one would hope the majority of the farmstead points would be in artificial areas but there is so much association of cropland, trees, and grass covers with farmsteads that the remainder was split into these covers.

Class 24 (landuse92 = 410 grass herbaceous > 70 CRP cover = 1)
1007 grass
94 tree
77 crop
36 artificial

This is extremely encouraging as most of the CRP program land in IOWA is planted in grass. The remainder can easily be explained as some of the CRP land may not be established or because of a very close association of the location of CRP program land with land still in crop or having tree cover.

Class 25 (landuse92 >= 610 and landuse92 <= 635 barren > 70)
3 artificial
1 water

This is extremely encouraging as most of the barren land points were in artificial cover map areas.

Class 26 (landuse92 = 640 grass herbaceous > 50 or water > 50)
7 grass
6 tree
8 crop
1 water

This is expected as the wetland points were fairly well distributed in all map classes.

Class 27 (landuse92 = 170 or landuse92 = 180 grass herbaceous > 90)
6 grass
1 tree
4 crop
1 artificial

This is encouraging as most other agricultural land with wildlife cover of herbaceous was in the grass map class where as the next highest occurrence was in cropland.

Class 32 (landuse92 = 400 crop > 90)
1 grass
1 crop

This is valuable even though there were only two points that were given farmstead designations with over 90% earth cover cropland.

Class 33 (landuse92 = 400 tree > 70 or shrub > 70)
2 tree
1 artificial

This is valuable even though there were only three points that were given farmstead designations with over 90% earth cover tree.

Class 34 (landuse92 = 400 grass herbaceous > 70)
43 grass
8 tree
19 crop
16 artificial

This is encouraging as most farmstead points with wildlife cover of herbaceous were in the grass map class areas where as the next highest occurrence was in cropland then artificial.

Class 39 (landuse92 = 640 tree > 50 or shrub > 50 or water > 50)
46 grass
8 tree
10 crop
30 artificial

There was no classification for wetlands and the points were located in map areas where they would be expected.

Class 40 (landuse92 = 700 or landuse92 = 730 tree > 70 or shrub > 70)
3 grass
8 tree
2 artificial

This is extremely encouraging as most of the points designated as urban land with tree or shrub earth cover was in the map areas of trees.

Class 41 (landuse92 >= 800 and landuse92 <= 845 grass herbaceous > 70)
25 grass
4 tree
2 crop
18 artificial

This is extremely encouraging as most of the points designated as transportation land with grass or herbaceous earth cover was in the map areas of grass with the next highest occurrence being in artificial.

Class 42 (landuse92 >= 800 and landuse92 <= 845 crop > 70)
56 crop
8 grass
3 tree
55 artificial

This is extremely encouraging as most of the points designated as transportation land with crop earth cover was in the map areas of crop and artificial.

Class 43 (landuse92 >= 800 and landuse92 <= 845 tree > 70 or shrub > 70)
5 tree
1 grass
1 artificial

This is extremely encouraging as most of the points designated as transportation land with tree or shrub earth cover was in the map areas of tree.

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