40 results about "Mercator projection" patented technology

A navigational plotter for use with a selected navigational chart and its method for production include providing a generally transparent elongated planar straight edge member having each of a first and a second straight edges parallelly disposed opposite one another bounding a generally rectangular interior surface. A printed central axis bisecting the rectangular interior surface and at least one compass rose arranged to have its North / South ordinal points to lie upon the printed central axis thus to allow the user to maintain orientation of the plotter on the chart. A first distance scale is calibrated in accord with the scale of the selected chart along a selected line of latitude. The first distance scale is printed to span the East / West ordinal points on the compass rose and along the first straight edge. A second distance scale is calibrated in accord with longitude according to a Mercator projection.

The invention discloses a method for calculating the risk degree of a ship hitting a bridge considering the scale of the ship. By establishing a plane rectangular coordinate system and using the Mercator projection method to convert the geographical position of the bridge and the ship according to the warning range of the bridge area, the rectangular coordinates are designed. The method of projecting the ship on the bridge axis along the channel direction uses the distance between the projected point and the center point of the pier to construct the risk algorithm of ship collision with the bridge. This algorithm fully considers the influence of ship size on the risk of ship collision with bridge, and uses the geometric analysis method to obtain the risk interval of ship collision with bridge from the horizontal direction, so that the algorithm is more in line with the actual situation. , and further proposed an active early warning and prediction strategy for ship collision with bridges. Through the above early warning strategy, the accuracy of early warning can be improved, the reliability and practicability of the system can be improved, and the common safety of bridges and ships can be guaranteed.

The present application discloses a method and device for drawing a delivery area, wherein the method includes: using the Mercator projection method to convert the latitude and longitude coordinates of the delivery site into plane coordinates S 0 (x 0 ,y 0 ); According to the plane coordinate S 0 (x 0 ,y 0 ), the radius r of the preset delivery area and the preset boundary drop point number N, determine the plane coordinates of each drop point evenly distributed on the delivery area boundary of the delivery site; the plane coordinates of all the drop points The coordinates are converted into corresponding latitude and longitude coordinates; and the delivery area is identified on the map according to the latitude and longitude coordinates of all landing points. By adopting the present invention, the drawing efficiency of the distribution area can be effectively improved and the accuracy is high.

The invention provides a global map data storage and organization method and a calling method. The global map data storage and organization method includes the steps of projecting a global map to a global coordinate frame, establishing a global geographic grid frame according to the global coordinate frame, slicing the global map to obtain tile data corresponding to the global map, and packaging and storing the tile data according to the geographic grid frame. The calling method includes the steps of receiving a map displaying request carrying longitude and latitude coordinates and displayinggrades, determining tile packets corresponding to the longitude and latitude coordinates according to the longitude and latitude coordinates and the displaying grades, and obtaining the tile data corresponding to the longitude and latitude coordinates from the tile packets. The complete global map is established by means of the Mercator projection in low-latitude areas and the ortho-axis azimuth projection in high-longitude areas; when the packaged and stored tiles are called, the target tile packets are retrieved from a relatively small number of tile packets, then the target tile data is retrieved from the target tile packets, the time consumed for retrieval is short, and the calling speed and efficiency of mass tiles are improved.

The present invention proposes a large data analysis method for farmland areas based on satellite remote sensing images, which analyzes point and polygon overlay, line and polygon overlay, and layer overlay analysis through overlay analysis to form a map database; The spatial data in the data files, including point layer files, line layer files, and surface layer files, are released uniformly according to the Mercator projection to form a planar map database; the aggregation function is used to realize dynamic vector slicing of spatial data, and the planar map database Data information is encoded into vector slices, saved as vector block data of various scales, forming a vector slice map; the front end displays the vector slice map, and provides catalog and metadata services, map services, feature services, image services, and 3D maps Service, place name address service and spatial data service to support the application of big data in farmland areas.