Geographic information system | August more challenges

This is the second day of my participation in the August Challenge. For more details, see:August is more challenging

GIS basics

GIS Data structure

  • The characteristics of geographical entities: attribute characteristics, spatial characteristics, and temporal characteristics
  • Types of geographic entity data: attribute data, geometric data, relational data

Data storage format in GIS

  • Vector data format: For GIS, points should be the essence of vector data. Points generate lines, lines generate planes… And thus constitute the vector space in the GIS world
  • Raster data format: Raster Data structure A data structure based on a raster model. It is a form of data organization that divides space into regular grids, called grid cells, and gives corresponding attribute values on each grid cell to represent geographic entities
  • Metadata: Description of geographic data and information resources. He describes and explains the content, quality, conditions and other features of geospatial data so that users can effectively locate, evaluate, compare, acquire and use geospatial data (generally speaking, data describing spatial data).

Data storage in GIS

  • SHP(Shapeflie)A Shape file consists of three files: a master file (.shp), an index file (.shx), and a dBASE(*.dbf) table
  • CAD: has some columns of data format: DWG file:DWG is the graphics file of AutoCAD, it is two or three dimensional graphics file. It and DXF files can be converted to each other. DXF file:DXF is a CAD data file format developed by Autodesk for CAD data exchange between AutoCAD and other software. DXF is an open vector data format. When using CAD data in GIS, standard CAD data will be marked with information such as the coordinate system used in the file
  • Tagged Image File Format (TIFF) is a File Format used to store images, including photos and art images. It was originally developed by Aldus in conjunction with Microsoft for PostScript printing
  • DEM: Digital Elevation Model (DEM) is a kind of physical ground Model that realizes the Digital simulation of ground topography (i.e., the Digital expression of terrain surface morphology) by means of limited terrain Elevation data. It represents the ground Elevation in the form of a group of ordered numerical arrays. It is a branch of Digital Terrain Model (DTM), and other Terrain feature values can be derived from it
  • GeoJSON: GeoJSON is a format for encoding various geographic data structures. A GeoJSON object can represent a geometry, a feature, or a collection of features. GeoJSON supports the following geometric types: point, line, plane, multipoint, multiline, multiface, and geometric collection. A feature in GeoJSON contains a geometric object and other properties, and a feature set represents a set of features. A complete GeoJSON data structure is always an object (in JSON terms). In GeoJSON, an object consists of a collection of name/value pairs, also known as members. The name is always a string for each member. The value of a member is either a string, number, object, array, or one of the following text constants: “True “,”false”, or” NULL “. Arrays are made up of the elements whose values are described above
  • Spatial database: the sum of the geo-spatial database related to the application of gis stored in computer physical storage media (the biggest difference from traditional database: Records spatial characteristics and data), common spatial databases include Postgresql (Postgis Extension), Mysql (Mysqlspatial Extension), Oracle (Oracle Spatial Extension), and so on

WebGis

What is the WebGis

  • WebGIS (Network Geographic Information System) : It is the extension and development of traditional GIS on the network. It has the characteristics of traditional GIS and can realize the basic FUNCTIONS of GIS such as spatial data retrieval, query, map output and editing. At the same time, it is the basis of geographic information publishing, sharing and communication collaboration on the Internet (generally speaking, it is web+ GIS).

conclusion

WebGIS is mainly used for spatial data release, spatial query and retrieval, spatial model service, Web resource organization, etc. WebGIS is the product of Internet technology applied to GIS development. With the expansion of Web functions, GIS has really become a tool used by the public. In the era of rapid development of science and technology, WebGIS plays an increasingly important role in our daily life and work, such as: Navigation, delivery, real-time bus, 5G car driverless, work in water conservancy, forestry, meteorology and other industries have great significance, add color to our life

The next phase of the beginning of actual combat code: Vue+ ArcGISAPI4.x

Thanks for watching, and if you have any questions, please leave them in the comments section