Development direction

Recently, the development and application of Geographic Information Systems (GIS) have increasingly focused on the Web side. Web side development indeed has more advantages than C/S development represented by C # ArcGIS Engine, and can easily achieve cross platform development through H5. Having been in this industry for a while, I remember that when I was in school, there was no one to guide me in development. I struggled to explore, but achieved half the result with twice the effort. Write this blog post to introduce the general route and introductory knowledge of WebGIS development to GIS students in school.

Firstly, there are four main types of development platforms for WebGIS:

1.Business Platform

ArcGIS, hypermaps, MapGIS, and other commercial platforms, among which ArcGIS JS is the most widely developed and applied, with stable performance and abundant learning materials and code.

2.Open source platform

There are many open source WebGIS platforms, such as OpenLayers, Leaflet, etc. Among them, OpenLayers has the most extensive applications, the most powerful functions, and has been constantly updated with a large number of users. Interestingly, when I opened the web development code of MapGIS earlier, I unexpectedly found the JS file of OpenLayers.

3.Map platforms such as Baidu and Gaode

Although these platforms are not born for GIS, their regularly updated maps save the trouble of building map servers during development. Many non GIS developers can also easily develop. For personal or non commercial applications, it is free of charge. In the actual development process, there are also many companies that do not focus on GIS development and are developing map platforms such as Baidu.

4.Underlying development based on WebGL or other graphical languages

The first three are all about secondary development. One time, a company that emphasizes its brand and status will develop lower level graphics based on WebGL or other technologies, which requires high GIS knowledge and algorithm preparation from developers. The development cycle is long, there is a lot of investment in the early stage, and there are fewer personnel involved in such development.

Development Skills Mastery

If you are a person who wants to enter WebGIS development, or a GIS student wandering in front of a book, here are the skills you need to prepare for WebGIS development

Knowledge structure

Before developing WebGIS, you must have a clear model of how WebGIS works and how maps are presented. You need to understand the following nouns and their relationships:

• Map server
• Map services (OGC, WMS, WFS, TMS, WMTS)
• GeoJson
• Map Slicing
• Background

Fundamentals of Development

• Html5, CSS, JavaScript - Common Foundation for Web Development.
• ES6- The new generation standard for JavaScript, and the new version of WebGIS platform mostly relies on ES6.
• Based on certain background development experience or knowledge, after all, it is necessary to query spatial data information from HTML pages in the background.

Introduction to the development of commercial platforms such as ArcGIS

Although there are many commercial platforms, let's talk about the most widely used ArcGIS JS development. When writing this article, the latest version is the ArcGIS API for JavaScript 4.8.

ArcGIS Desktop Basic Operations - Proficient in simple data processing and coordinate system conversion.

ArcGIS Server - can publish various map services.

ArcGIS API for JavaScript can call various map services.

You can use ArcGIS Server to publish spatial processing services (higher level requirements)

OpenLayers and other open-source platform development

GeoServer - Similar to ArcGIS Server, open source map server, usually paired with open source map platforms.

Udig - used to configure map styles in GeoServer.

PostgreSQL and PostGIS - open source spatial database, storing data and simple analysis.

Gaode and other map platforms

If you know the first two types of development, Baidu, Gaode, Tencent Maps, etc., you won't find it difficult anymore. Knowing JavaScript language and comparing it with official development documents and tutorials, it is easy to write it out.

Summary

The low-level development based on WebGL or other graphical languages is not suitable for GIS novices. It requires you to work for a few years and summarize some things yourself. If you do it again, it will be more practical and you will know where to optimize during the development process.

GIS developers, when they don't understand, development documents and official demos are the best teachers. I often encounter many people who ask about official development documents and demos, but in doing so, no one is willing to tell you too much.