Hyperspectral canopy sensing of paddy rice aboveground biomass at different growth stages

Non-destructive estimation of rice plant nitrogen status with Crop Circle multispectral active canopy sensor

Intelligent transportation systems (ITS) and navigation systems usually demand good timeliness on their used vector road network maps. Unfortunately, existing methods for road network map generation, such as the surveying method and the satellite image digitizing method, are difficult to generate up-to-date road network maps. This paper presents a method for automatic generation of road network map from massive GPS vehicle trajectories, which can generate the up-to-date road network map from the up-to-date GPS vehicle trajectory data that can be widely available. Given a set of GPS vehicle trajectory data, the input first is processed to construct a road network bitmap which depicts the road network. Then the road network skeleton on the bitmap is computed. Finally, the road network graph extraction is implemented on the skeleton to generate the vector road network map data. To evaluate the presented method, we implemented and tested it on the massive GPS vehicle trajectory data collected in Jilin City, China. The test results demonstrate that the presented method can be promising in applications.

Automatic generation of road network map from massive GPS, vehicle trajectories

Abstract Basin delineation is a major preliminary of hydrologic modeling and watershed management. An efficient method to delineate topographic basins from digital elevation models is presented. It is based upon mathematical morphology and it consists of two major steps. First, remove all the pits within the model by using an original morphological mapping, and second, delineate topographic basins by using morphological thinnings with specific structuring elements. The results are consistent with real terrain features. In a more general way, the proposed methodology illustrates the segmentation approach provided by the morphological watershed mapping.

Automated basin delineation from digital elevation models using mathermatical morphology

Timely nondestructive estimation of crop nitrogen (N) status is crucial for in-season site-specific N management. Active crop canopy sensors are the promising tools to obtain the needed information without being affected by environmental light conditions. The objective of this study was to evaluate the potential for the GreenSeeker active crop canopy sensor to estimate rice ( Oryza sativa L.) N status. Nine N rate experiments were conducted from 2008 to 2012 in Jiansanjiang, Heilongjiang Province in Northeast China. The results indicated that across site-years and growth stages, normalized difference vegetation index (NDVI) and ratio vegetation index (RVI) obtained with the GreenSeeker sensor could explain 73%–76% and 70%–73% of rice aboveground biomass and plant N uptake variability in this study, respectively. The NDVI index became saturated when biomass reached about ${\bf 4\nbsp\hbox{t}\nbsp\hbox{ha}^{ - 1}}$ or when plant N uptake reached about ${\bf 100\nbsp\hbox{kg}\nbsp\hbox{ha}^{ - 1}}$ , whereas RVI did not show obvious saturation effect. The validation results, however, indicated that both indices performed similarly, and their relative errors (RE) were still large ( $ {\bf \gt 40\% }$ ). Although the two indices only explained less than 40% of plant N concentration or N nutrition index (NNI) variability, the RE values were acceptable ( ${\bf \lt 26\%} $ ). The results indicated some potentials of using the GreenSeeker sensor to estimate rice N status nondestructively, but more studies are needed to further evaluate and improve its performance for practical applications.

In-Season Estimation of Rice Nitrogen Status With an Active Crop Canopy Sensor

It is very important to know the spectral characteristics for the sake of understanding the remote sensing data. The reflectance characteristics of paddy field canopies vary with time or observational conditions (solar zenith angle, solar azimuth angle, and view zenith angle). A number of field studies have clarified the effects of these conditions on grain canopy reflectance. Most of the field data used in these study, however, were conducted only through the growing season in one year or by grains planted in pots. A series of authors’ experiments were initiated in 1982 and continued from the spring to the autumn every year to 1987. In this study we describe that the remotely sensed spectral data measured on the ground are influenced not only by the grain type, observational conditions, and growing season but also by the solar zenith angle, solar azimuth angle and view zenith angle in relation to scene. In this paper we report the results from the investigation of these various fundamental prope...

Effects of solar and view angles on reflectance for paddy field canopies

Much local government has been using a large scale digital map with Geographic Information System (GIS). However, the updating method of a map is not established yet, and there are very few successful examples. The purpose of this study is the application of REAL TIME GIS using remote sensing and RTK-GPS for local government. REAL TIME GIS is the system for real-time mapping and updating at the field site using Real-time Kinematic Global Positioning System (RTK-GPS), GIS and cellular phone. This system has the problem that RTK-GPS positioning data is Japanese Geodetic Datum 2000 (JGD2000) of WGS-84, but most of the digital maps of local government are still Tokyo Datum of old geodetic system. It is necessary to transform an old geodetic system to a new one. We used Affine Transformation for this problem. In this paper, the parameters which were calculated by Affine Transformation were named "High-Accuracy Regional Parameter (HARP)". As a result, Affine Transformation has 2 cm errors using 4 control points at the corner of unit. In conclusion, the need of HARP with Affine Transformation was indicated. It is suggested that the process of REAL TIME GIS and HARP should be introduced to the work of local government

Application of REAL TIME GIS using remote sensing and RTK-GPS for local government

It is well known that in the Noto area in Hokuriku district of Japan, landslides occur in all seasons. Most small-scale landslides, which the authors have investigated, occur near streams in valleys with a gentle slope. Moreover, it is said that underground-water supplied by rainfall and snowfall strongly relates to these landslides. The objective of this study is to find areas where landslides may occur in the near future by using infrared band data and visible band data obtained from a Landsat TM sensor with Thematic-Mapper data related to landslide areas. As a result, at many landslide segments in investigated areas, the authors found that the surface temperature in landslide areas is higher than in non-landslide areas. >

Extraction of characteristic properties in landslide areas using thematic map data and surface temperature

Spatial features of watersheds are examined to clarify characteristic properties in areas where landslides may occur. In this study, first, a method for delineating watersheds from the digital terrain data is described. Next, the area (A), mean slope (S) and form factor (F=A/L2) of watersheds are estimated. Here, L is the length of the main stream in a watershed. As a result, it is shown that topographic features in landslide areas are successfully characterized by a linear combination of the normalized values of A, S and F.

https://ieeexplore.ieee.org/iel2/1014/12511/00578302.pdf

Extraction of Landslide Areas Using Spatial Features of Topographic Basins

The authors have already conducted an analysis of landslide areas with remote sensing data and thematic map data respectively. Estimation of landslide areas, however, has been considered very difficult because the principal factor of landslide complexly relates to some phenomena. The objective of this study is to find areas where landslides may occur in the near future by using satellite remote sensing data and thematic-map data related to landslide areas with GIS (geographic information system) techniques. The authors' research focused on the actual vegetation in landslide areas. The relationship between vegetation and landslide areas were extracted with the thematic maps including an actual vegetation map.

https://ieeexplore.ieee.org/iel3/4810/13413/00615841.pdf

M. Shikada

Papers

Effects of solar and view angles on reflectance for paddy field canopies

Application of REAL TIME GIS using remote sensing and RTK-GPS for local government

Extraction of characteristic properties in landslide areas using thematic map data and surface temperature

Extraction of Landslide Areas Using Spatial Features of Topographic Basins

An application of GIS information and remotely sensed data for extraction of landslide