3. System functions
3.1. Operations and viewing of maps
Users could view administrative area map and soil nutrient thematic maps of Jianshui County with the
system on Windows mobile phone or PDA. Some toolbars were designed at the bottom of the interface,
with which users could zoom, pan, and refresh maps. Mapcontrol widget provided by eSuperMap was
used to display maps. Map operations such as zooming, panning and other operations, were realized by
using the action method in mapping class.
Soil nutrient thematic maps such as total nitrogen, total potassium, total phosphorus, available nitrogen,
phosphorus, potassium, PH value, organic matter, fertility level, could be viewed by users. Soil nutrient
thematic maps were raster data generated by Kriging spatial interpolation of the sampling point in the
Deskpro 6. As the raster data was too large and storage space of embedded devices was limited, so raster
data was not used directly on embedded devices. We must convert raster data to a format supported by
embedded devices. Those raster data would be saved as image data, and then be compressed to sit format.
The data with sit format took up little storage space. The system accessed the sit format data in the
embedded device by the method of external data source. Users clicked the menu of viewing thematic
maps in the navigation interface to entry the interface of thematic maps. Figure 2a was the thematic map
of phosphorus. Users could switch the thematic map by selecting the name in the drop-down list widget at
the top of the interface. The legends of the thematic maps which could be on or off by clicking the legend
menu on bottom right corner of the interface. We also can choose the toolbar at the bottom of the
interface to operate the thematic map.
3.2 Information inquiring
Information inquiring function mainly provided users with inquiring for soil fertility and information of
villages in Jianshui County. There were two methods to inquiry information about soil fertility: map
query method and text query method. When uses chose map query method, users selected a place by
clicking on a location on the County map; fertility information of the location area would pop up in the
form of a message box to users. Figure 2b showed the results of map query method. Text query method
meant users need to input the town and country’s name firstly, and then clicked the query button to get
information. Map query method was realized by the way of calling the click method in mapcontrol class
from eSuperMap library to search the spatial data set for fertility information. Text query method mainly
used query-by-general method in Dataset Vector class to search spatial data sets. Information of townsand villages was inquired from the SQL CE database by SQL statement, and then the results searched
would be shown to users in text form.
3.3 Fertilizer Recommendation
According to soil nutrient balance method, the system realized fertilizer recommendation for potash
nitrogenous and phosphate fertilizer [6]. The nutrient uptake amount per 100 kg of common crops such as
rice, corn, potatoes, nutrient content and utilization ratio of commonly used fertilizer were stored in SQL
CE database. Soil nutrient data was obtained from spatial data. Users only need to submit the name of
crop and the target yield to the system. The system would automatically calculate the fertilizing amount
per acre according to the fertilizer formula. Figure 2c showed the submission interface of parameters for
fertilizer recommendation.
3.4 System maintenance
System maintenance accomplished data maintenance. Data included spatial data stored in PMF and
general data stored in SQL CE database. We could use Windows smart phone or PDA to add, delete,
move soil sampling points and edit attribute of sampling points on the map. We also could add, modify,
and delete the data stored in SQL CE with the system.
4. Conclusions
This paper shows a new soil fertility information system which uses the embedded GIS technology
to develop. It is easy to carry and use that the system runs on Windows mobile 6.5 smart phone or PDA.
Users could inquiry soil nutrient information, get fertilizer recommendation, view soil nutrient thematic
map and manage spatial data with the system on smart phone without restrictions of network and the
location. System is stable and reliable when it works, which solves the problem that the traditional soil
fertility is not convenient to use directly in the fields. The system can provide information services and
fertilizer decisions for farmers, and also provides the decision for governor when they make agricultural
policies. The System is successfully applied in Jianshui County, which proves that using embedded GIS
to develop soil information system is feasible.
3. System functions3.1. Operations and viewing of mapsUsers could view administrative area map and soil nutrient thematic maps of Jianshui County with thesystem on Windows mobile phone or PDA. Some toolbars were designed at the bottom of the interface,with which users could zoom, pan, and refresh maps. Mapcontrol widget provided by eSuperMap wasused to display maps. Map operations such as zooming, panning and other operations, were realized byusing the action method in mapping class.Soil nutrient thematic maps such as total nitrogen, total potassium, total phosphorus, available nitrogen,phosphorus, potassium, PH value, organic matter, fertility level, could be viewed by users. Soil nutrientthematic maps were raster data generated by Kriging spatial interpolation of the sampling point in theDeskpro 6. As the raster data was too large and storage space of embedded devices was limited, so rasterdata was not used directly on embedded devices. We must convert raster data to a format supported byembedded devices. Those raster data would be saved as image data, and then be compressed to sit format.The data with sit format took up little storage space. The system accessed the sit format data in theembedded device by the method of external data source. Users clicked the menu of viewing thematicmaps in the navigation interface to entry the interface of thematic maps. Figure 2a was the thematic mapof phosphorus. Users could switch the thematic map by selecting the name in the drop-down list widget at
the top of the interface. The legends of the thematic maps which could be on or off by clicking the legend
menu on bottom right corner of the interface. We also can choose the toolbar at the bottom of the
interface to operate the thematic map.
3.2 Information inquiring
Information inquiring function mainly provided users with inquiring for soil fertility and information of
villages in Jianshui County. There were two methods to inquiry information about soil fertility: map
query method and text query method. When uses chose map query method, users selected a place by
clicking on a location on the County map; fertility information of the location area would pop up in the
form of a message box to users. Figure 2b showed the results of map query method. Text query method
meant users need to input the town and country’s name firstly, and then clicked the query button to get
information. Map query method was realized by the way of calling the click method in mapcontrol class
from eSuperMap library to search the spatial data set for fertility information. Text query method mainly
used query-by-general method in Dataset Vector class to search spatial data sets. Information of townsand villages was inquired from the SQL CE database by SQL statement, and then the results searched
would be shown to users in text form.
3.3 Fertilizer Recommendation
According to soil nutrient balance method, the system realized fertilizer recommendation for potash
nitrogenous and phosphate fertilizer [6]. The nutrient uptake amount per 100 kg of common crops such as
rice, corn, potatoes, nutrient content and utilization ratio of commonly used fertilizer were stored in SQL
CE database. Soil nutrient data was obtained from spatial data. Users only need to submit the name of
crop and the target yield to the system. The system would automatically calculate the fertilizing amount
per acre according to the fertilizer formula. Figure 2c showed the submission interface of parameters for
fertilizer recommendation.
3.4 System maintenance
System maintenance accomplished data maintenance. Data included spatial data stored in PMF and
general data stored in SQL CE database. We could use Windows smart phone or PDA to add, delete,
move soil sampling points and edit attribute of sampling points on the map. We also could add, modify,
and delete the data stored in SQL CE with the system.
4. Conclusions
This paper shows a new soil fertility information system which uses the embedded GIS technology
to develop. It is easy to carry and use that the system runs on Windows mobile 6.5 smart phone or PDA.
Users could inquiry soil nutrient information, get fertilizer recommendation, view soil nutrient thematic
map and manage spatial data with the system on smart phone without restrictions of network and the
location. System is stable and reliable when it works, which solves the problem that the traditional soil
fertility is not convenient to use directly in the fields. The system can provide information services and
fertilizer decisions for farmers, and also provides the decision for governor when they make agricultural
policies. The System is successfully applied in Jianshui County, which proves that using embedded GIS
to develop soil information system is feasible.
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