This paper is an extended version of a contribution presented
at the Graphiñon 2025 conference.
Satellite images are now one of the most frequently used materials for studying natural objects. Analysts analyze satellite images to recognize natural or man-made objects and use the resulting data for analytics and forecasting. Artificial intelligence technologies based on machine learning and computer vision methods typically serve as tools in this research.
Combining artificial intelligence capabilities with geoinformation technologies solves several important interrelated tasks.
First, it visualizes the contours of studied objects on
a satellite image. Second, during regular observations, it accumulates
material for analytics and forecasting possible changes in the contours and areas of
target objects using only a computer workstation. Thus, one can observe changes in the contours of target
objects over a certain period and, after accumulating sufficient data, forecast the further territory
development. A high-quality forecast
is crucial for decision-making in managing both specific
resources and the entire study area.
In the last decade, many Russian and foreign scientists have dedicated research to exploring artificial
intelligence capabilities for recognizing natural and anthropogenic objects on satellite
images, visually highlighting their contours and occupied areas. Some focus on
highly reliable recognition and visualization of studied objects and their automated categorization
and typification. Researchers typically combine applied machine learning methods, often using
a neural network as the primary combination method. For example, [1] describes using the
Net deep learning neural network combined with the ES Net semantic neural network to study forest
conditions; [2] considers using time series and a multiscale geographically weighted regression (MGWR)
model, where the Random Forest method recognizes data from satellite images in crop research. Other
studies focus on forecasting situation development regarding changes in the contours of studied objects. The main subjects of study
are natural objects – forests, agricultural lands and cultivated plantations, watercourses and reservoirs,
coastal zones of rivers, seas, and oceans. For instance,
study [3] focuses on forecasting crop development,
particularly wheat, using five different machine learning algorithms (Random Forest, Gradient Boosting,
AdaBoost, LightGBM, and XGBoost); concluding on their performance, it considers
the XGBoost model the most successful. Furthermore, using data from multiple sources combined with machine
learning algorithms increases forecasting accuracy and adds
new capabilities to agricultural decision support systems. A similar conclusion appears in study
[4], which applies small area estimation methods
and statistical regression methods combined with data from open sources – the Landsat
8 satellite and the Google Earth Engine platform – for researching forest quality.
Work [5] describes the Segment Anything Model (SAM), which performs image segmentation. This article
shows how researchers can adapt such foundation models for Earth remote sensing
tasks. The authors of [6] focus on solving the problem of precise boundary
extraction in remote sensing images by using contextual information.
For the presented research, we selected natural objects located in the
Bolsheboldinsky District of the Nizhny Novgorod Region,
which hold substantial value for
this territory – forest areas. The significance of these natural objects and the applied
methods make the research relevant and in demand.
Experts widely use remote sensing data to study objects occupying large areas on the Earth's surface. Forest areas undoubtedly belong to such objects [7]. Most often, researchers
obtain this data from satellite imagery, aerial photography, and images
from unmanned aerial vehicles. Since the latter two sources require
specific tools and are not always freely accessible, we decided to use satellite image repository materials available
to a wide range of users. From existing open sources, we selected images of the
study area from 2014 to 2024, taken by Landsat 8 and 9 satellites during the vegetation period (May
to September) in good, clear, and cloudless weather, as such images required fewer preliminary processing procedures.
We could use these images to create a geoinformation model visualizing the contours
of studied objects on a raster image.
Processing remote sensing data of the earth's surface from satellite images in geoinformation systems allows specialists to
work with all the region's natural resources or focus on individual, most important objects. This work required a sufficiently efficient and relatively simple algorithm
for recognizing images of the studied natural objects on satellite images, visualizing their contours, and using the results for further solutions.
Forest areas belong to the
category of objects lacking typical contours, which visual analysis of the selected satellite image fragments confirms (Fig.1).
This complicates recognizing and visualizing their contours on satellite images using the recently widespread convolutional
neural networks (CNNs). We believe that using a classic "supervised" neural
network algorithm, which includes the error backpropagation method, is more acceptable
for recognizing forest area images. They also considered the requirement for resource
economy during algorithm development and implementation.
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|
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(a)
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(b)
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Fig. 1. Fragments of vector layers of an image with forest areas: (a) -- fragment 1; (b) -- fragment 2
The following stages of working with the selected
images within the considered approach
involved applying geoinformation technologies and took place in the QGIS geoinformation system:
- Assembling a raster image using the GDAL Tools module;
- Selecting image scenes containing the study area;
- Separating scene fragments containing forest areas;
- Modeling forest areas using QGIS plugins [6];
- Obtaining a labeled singl channel raster with images of forest areas.
During image assembly, we took data from channels 1 to 7 and combined
them in the GDAL Tools QGIS virtual environment. Then, on the
selected image fragments containing forest areas, we added vector layers for
labeling and classifying forest area images using reference polygons.
Within this research, visualizing forest area images means
performing a dichotomous classification of the selected satellite image scene
fragment, which produced singl channel rasters with two
types – belonging to forest areas and not belonging
to them. The primary research method – a neural network algorithm – performed
this classification. We prepared training datasets for
it using four wel known machine learning algorithms – Gaussian Mixture
Model, Random Forest, Support Vector Machines,
Nearest Neighbors, implemented in QGIS via buil in plugins [8]. After
preparing the datasets and training the neural
network, we performed recognition and
visualization of forest area contours on the selected satellite image fragments. The
visualization results of forest areas by the neural
network algorithm are shown for fragment 1 (Fig. 2) and fragment 2 (Fig. 3) with training
sets prepared by each mentioned method.
Note that in previous stages of the research
described in [9], the neural network algorithm used 14 input nodes
and two activation functions, ReLu and Softmax, as it needed to implement dichotomous
classification. We implemented the network in the Python
programming language, using functions from the Numpy, PirsGis,
and ensorFlow libraries.
However, when trying to implement the algorithm in the open
QGIS geoinformation system, we discovered that not all QGIS versions could run it correctly. Therefore, they modified the algorithm to eliminate these
problems as follows: to increase accuracy, they
used 64 nodes and the same activation functions, serving the Python libraries numpy, pirsgis,
sciki learn. This modification should allow its future use as a plugin for the ope
source GIS QGIS, expanding its application possibilities and potentially representing certain novelty in the conducted research.
Fig. 2. Visualization of forest areas on fragment 1 with training sets prepared by
methods: (a) -- Gaussian Mixture Model; (b) -- K-Nearest Neighbors; (c) -- Random Forest; (d) -- Support Vector Machines
Fig. 3. Visualization of
forest areas on fragment 2 with training sets prepared by methods: (a) --
Gaussian Mixture Model; (b) -- K-Nearest Neighbors; (c) - Random Forest; (d) -
Support Vector Machines
After training using datasets prepared with the mentioned machine learning methods, the neural network showed generally
acceptable results in the confusion matrix and corresponding metrics – robustness,
recall, and overall accuracy. This allows considering the predicted visualization values satisfactory and indicative of achieving
the set goals.
Table 1 presents the confusion matrix data for visualizing forest
area images on fragment 1; Table 2 shows data for fragment 2. The table data indicates that the
fragment with a larger number of forest areas recognizes as effectively and reliably as the fragment with
fewer forest areas, suggesting the algorithm independence from the number of pixels
of recognizable objects.
Table 1. Confusion Matrix Data for Fragment 1
|
Training Set
|
TN
|
FN
|
FP
|
TP
|
|
GMM
|
17657
|
115
|
299
|
5629
|
|
KNN
|
17747
|
427
|
104
|
5422
|
|
RendF
|
17371
|
122
|
516
|
5691
|
|
SVM
|
17243
|
268
|
263
|
5926
|
Table 2. Confusion Matrix Data for Fragment 2
|
Training Set
|
TN
|
FN
|
FP
|
TP
|
|
GMM
|
17276
|
33
|
680
|
5711
|
|
KNN
|
17567
|
180
|
180
|
5669
|
|
RendF
|
17792
|
523
|
95
|
5290
|
|
SVM
|
17264
|
268
|
242
|
5926
|
Metrics calculated on the basis of confusion matrix show sufficient accuracy and success
of the neural network algorithm with each
prepared dataset (see tables 2). However, one can discuss more or less successful algorithm runs with some
training sets and identify the set that is most stable with the developed neural
network algorithm. As Fig. 4 shows, the algorithm is most stable with the training dataset prepared using
the Support Vector Machines (SVM) method.
The neural network metrics are higher compared to those described in [7],
ranging within: accuracy 0.9-0.98, precision 0.9-0.98, recall 0.9-0.98.
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(a)
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(b)
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Fig. 4. Visualization of
neural network algorithm metric values: (a) -- fragment 1; (b) -- fragment 2
Since we obtained positive experience with
training datasets for the neural network by machine learning methods that
inherently introduce certain deviations, we further continued the series of
experiments with the neural network algorithm. For this, a raster obtained
through precise interpretation using the Google Earth Explorer base layer was
used as the second component of the training dataset.
Finally, we got a
single-channel raster. This, paired with a multi-channel raster of similar
dimensions for the selected territory, constitutes the training dataset for the
neural network algorithm (Fig. 5).
Fig. 5. Training
dataset prepared through precise interpretation
Subsequent work focused on selecting optimal
values for the neural network parameters: the number of training epochs and the
number of tests during training to determine the minimum standard deviation
value.
As follows from the test analysis the
algorithm with the number of training epochs set to 14 and 2 consecutive
experiments during the training configuration (Table 3) demonstrated the most
stable performance. This configuration also shows the most reliable prediction
result when compared with reference values (Fig. 6).
Table 3. Neural Network parameter definition
|
Training Epochs
|
Training tests
|
precision
|
recall
|
accuracy
|
|
12
|
2
|
0,979
|
0,991
|
0,97555
|
|
12
|
3
|
0,978
|
0,992
|
0,97610
|
|
12
|
4
|
0,980
|
0,991
|
0,97064
|
|
12
|
6
|
0,974
|
0,994
|
0,97608
|
|
14
|
2
|
0,974
|
0,994
|
0,97517
|
|
14
|
2
|
0,977
|
0,992
|
0,97681
|
|
14
|
2
|
0,969
|
0,996
|
0,97327
|
|
14
|
4
|
0,983
|
0,987
|
0,97712
|
|
14
|
4
|
0,980
|
0,991
|
0,97759
|
Fig. 6. A photo fragment and the output after processing it with a neural network
Analysis of the obtained results clearly
showed that the developed algorithm extracts contours of plane geometric shapes
with complex, irregular structures at an accuracy acceptable for subsequent
research stages. Thus, the standard training metrics of the neural network
algorithm with the final selected parameter values had the following stable
indicators: precision - 0.97, recall - 0.99, accuracy - 0.98. The standard
deviation varied in the range from 0.0001 to 0.0008.
At this research stage, the authors conclude
that automated methods for recognizing objects on satellite images require more
thorough preparation of initial data. Specifically, machine learning algorithms
can prepare the training dataset. This approach will yield a more accurate
geoinformation model of the study area, visualizing the contours and areas of
the studied objects. The modified neural network algorithm, with an increased
number of nodes and optimized library usage, showed stable and high
performance, particularly with the SVM-prepared training set. This success paves
the way for integrating the algorithm as a plugin into the open-source QGIS,
enhancing its accessibility for a broader range of specialists. The main focus
of the model's improvement is extending it to other types of objects of various
natures, not only in satellite but also in other images, as well as expanding
the capabilities of temporal analysis to detect and predict long-term changes
in objects. Several approaches in this direction hold significant interest. For
instance, work [10] addresses long-term change forecasting and describes modern
methods for monitoring forests using Landsat time series. Furthermore, modern
Transformer architectures [11], [12] for forest mapping, which are now
replacing purely convolutional networks, also show great promise.
1. Wang, Y., Zhang, Z., Xia, J., Zhao, F., & Dong, P. (2025). ES-Net Empowers Forest Disturbance Monitoring: Edge–Semantic Collaborative Network for Canopy Gap Mapping. Remote Sensing, *17*(14), 2427. https://doi.org/10.3390/rs17142427.
2. Xiao, P., Zhou, Y., Qian, J., Liu, Y., & Li, X. (2025). Spatiotemporal Mapping and Driving Mechanism of Crop Planting Patterns on the Jianghan Plain Based on Multisource Remote Sensing Fusion and Sample Migration. Remote Sensing, *17*(14), 2417. https://doi.org/10.3390/rs17142417.
3. Rufaioglu, S. B., Bilgili, A. V., Savasl?, E., Ozberk, I., Aydemir, S., Ismael, A. M., Kaya, Y., & Matos-Carvalho, J. P. (2025). Sensor-Based Yield Prediction in Durum Wheat Under Semi-Arid Conditions Using Machine Learning Across Zadoks Growth Stages. Remote Sensing, *17*(14), 2416. https://doi.org/10.3390/rs17142416.
4. Alegbeleye, O. M., Poudel, K. P., VanderSchaaf, C., & Yang, Y. (2025). Improving the Estimates of County- Level Forest Attributes Using GEDI and Landsat-Derived Auxiliary Information in Fay–Herriot Models. Remote Sensing, *17*(14), 2407. https://doi.org/10.3390/rs17142407.
5. Chen et al. (2023). "A Survey on Segment Anything Model (SAM) for Vision Foundation Models in Remote Sensing." IEEE Geoscience and Remote Sensing Magazine.
6. Wang et al. (2023). "Boundary-aware Contextual Network for Remote Sensing Image
7. Gabitova, A.A. Remote Sensing and GIS in Assessing Forest Encroachment on Unused Agricultural Lands. Advances in Current Natural Sciences, 2022, no. 11, pp. 42-46. Access mode: https://natural- sciences.ru/ru/article/view?id=37926.
8. QGIS Python Plugins Repository. Dzetsaka Plugin [Electronic resource]. Access mode: https://plugins.qgis.org/plugins/dzetsaka/#plugin-about.
9. Popov, E.V., Yurchenko, P.V. Using a Neural Network for Geometric Modeling of Natural and Anthropogenic Objects. Privolzhsky Scientific Journal, 2024, no. 4, pp. 336-341.
10. Segmentation." ISPRS Journal of Photogrammetry and Remote Sensing, Vol. 205, pp. 278-293.
11. Tucker et al. (2024). "Near-Real Time Global Forest Change Monitoring with Landsat." Remote Sensing of Environment, Vol. 304, 114066.
12. Tarasiuk et al. (2023). "ForestFormer: A Deep Learning Approach for Forest Cover Mapping Using Multi-Temporal Satellite Imagery." International Journal of Applied Earth Observation and Geoinformation, Vol. 125, 103568.