Principle of map cutting based on ArcIMS, mapbar, Google, 51 Ditu, mapabc)

Recently, I just modified and sorted out some of the original text, mainly about the fixed range of map pre-generation technology based on ArcIMS, with a completeAlgorithmDescribe and post it for your reference. All content comes from your own project experience and learning relevant information on the Internet. Recently, many of my friends have been studying this issue, all those who wish to be able to do things will be more or less helpful to everyone's work.

This article briefly describes the map cutting, and briefly introduces the current situation of the Web Map Service Based on the pre-generated technology.

Due to the rush of time, there must be some inaccuracy or errors in the middle. I hope the experts will give us some advice so that I can better organize it!

Thank you! Related attachments

The buffer mechanism is required to increase the speed, which is a bit complicated. I am also doing image display, so it is necessary to use this online system, ArcIMS is very slow, with the help of pre-generation can save the time for the server to generate images.

This is already very popular in foreign countries, and some companies in China have implemented it, but they do not have complete Learning documents. So I have sorted out the materials collected at ordinary times, and I do not know whether to express them clearly, hope to correct more!

If you do not understand some issues related to projection and coordinates in this article, refer:
I don't know whether the 51ditu and other online map services can process data directly into images of different levels. Instead, we should first load the data into a database platform to generate image data of different levels. It is easier to use the platform to manage and maintain data. That's what I think now. I don't know how the general practice works?

 

The general idea is to pre-generate map images, but the storage and request mechanisms of map files are different.
For example, a map request for yahoomaps is as follows:
Http://maps.yahoo.com/#mvt=m&trf=0&lon=-94.619236&lat=40.22817&mag=6

A map request for googlemaps is as follows:
Http://mt3.google.com/mt? N= 404 & V = w2.43 & X = 2 & Y = 5 & zoom = 13

A map request for mapbar is as follows:
Http://img.mapbar.com/maplite/mapbank/baidu/7/56_14/9_0.png

A map request for 51ditu is as follows:
Http://bimg.51ditu.com/12/13194143727625.png

A map request of sogoumap is as follows:
Http://pic1.go2map.com/seamless/0/174/722/0/0/25_7.GIF

Etc...

As can be seen from the above, Google & Yahoo all request the map location parameters customized by the general or its system, and the domestic users all use the direct image URL link to obtain the image, this is slightly less secure (of course, Google Images are easy to download ).

The image response mechanism of the above-mentioned company servers is not clear, but Google's map server will soon be able to identify whether users are downloading maps in batches and soon block customers' IP segments, so that the computer in the LAN cannot request map images for the moment.

As for their respective buffer mechanisms, I have not systematically studied them. I have only tested map services such as 51ditu that can still browse the previously viewed images after the NIC is disconnected, indicating that they are indeed buffered on the client, hope you can advise me How to buffer it!

For simple raster of Vector Data, ArcXML cut graph using ARCIMS should be the best solution. For 3D data like ecity and metropolitan area, we need to use CAD & 3dmax and its plug-in. We are studying it. After that, we will write another article to share it with you.

The above is a pre-generated map tile with a fixed range. The fixed scale is just sorted out and uploaded for your reference. Thank you for your advice!

Attachment