Implementation Principle of Map Component Drag circle (PART 1)
As long as you understand the implementation, the idea is the same regardless of which map rendering engine you use, adding (clearing) circles and adding (clearing) points to the map API. The following figure shows an example function
Leaflet draws the global data distribution of Novel Coronavirus and all provinces and cities in China
Map the distribution and heat map of COVID-19 infection worldwide. Map the distribution and heat map of COVID-19 infection in various provinces and cities in China
Arcgis Server publishing map service problems and solutions (continuously updated)
1. Map service startup failure When the service is stopping and you manually start the service, a message is displayed indicating that port 4000 is occupied. At this time, the program javaw.exe of the server is found to occupy the port, and you need to manually servre ArcGIS
GIS coordinate system mapping principle: geoid/datum/reference ellipsoid /EPSG/SRI/WKT
How does the geoid reference ellipsoid approach the earth surface step by step, and what are the differences of geocentric geodetic coordinate system and parameter-centered geodetic coordinate system caused by the difference between the center of the earth ellipsoid and the earth centroid? EPSG:4479 and EPSG:4480, Mercator projection and pseudo Mercator projection
Cesium is a solution for stalling when loading a large number of Label entities
The author contacted CesiumJS because of the company's project needs, directly learning while developing, two or three months have been quite smooth. As the volume of data grew and the number of entities on the map increased, the first screen would often lag when loading, the client's machine would perform poorly, and sometimes the browser would be unresponsive at the same time. The test classified the problem as a BUG that had to be fixed, which made my head go crazy. When I need...
OpenLayers-Control
This is the 16th day of my participation in the August Text Challenge. For example, control map size through buttons, add decoration on map map, etc. In Openlayer
Kernel density estimation (KDE) principle and implementation
In statistics, Kernel Density Estimation is used to infer the distribution of population data based on limited samples. In this paper, the principle of Kernel Density Estimation is discussed and implemented on this basis
Openlayers Offline Map (1)
This is the first day I participated in the August More Text Challenge, the activity details view: August more text Challenge Preface Based on the internal network restriction, so need to implement an offline version of the map. When it comes to offline maps, we should talk about online maps. Autonavi and Tencent maps can be seen in many software, like
Leaflets load tile maps with different projections
Since the vector data used in the project were unified as the Geodetic 2000 coordinate system (ESPG:4490), and the remote sensing image data adopted a variety of coordinate systems, a tile map solution of leaflets loading different projections was proposed according to the requirements
Tencent Map - Key word input prompt (with video at the end)
The keyword input prompt interface can be used to obtain the completion and prompt of the input keyword to help users enter quickly. The effect of Autocomplete can be achieved by combining with the front-end program.