Google Earth interacts with ArcGIS data (iv)

The "Google Earth and ArcGIS Data Interaction" series is divided into four articles, which is the last article. The main solution is to download the DEM and use the downloaded DEM for three-dimensional modeling.

There are two kinds of free dem on the Internet, one is SRTM90, the other is Aster gdem.

SRTM Download website for:

http://srtm.datamirror.csdb.cn

ASTER gdem Download Website:

http://www.gdem.aster.ersdac.or.jp/

This article takes Aster Gdem as an example, on the merits of two kinds of data online has a lot of information, here is not to repeat.

The relevant parameters of the ASTER Gdem are shown in the following table:

　　

Each Gdem shard consists of two compressed files, a digital elevation model (DEM) file, and a quality assessment (QA) file. As shown in the following:

　　

The file name of each data file is generated according to the latitude and longitude of the bottom left (southwest) corner of the Shard Geometry Center. For example, the lower-left coordinate of the astgtm_n40e116 file is 40 degrees north latitude and 116 degrees east longitude. Astgtm_n40e116_dem and Astgtm_n40e116_num correspond to data for digital elevation model (DEM) and quality control (QA) respectively.

Detailed Download method

Open the website to register.

　　

Login, login and click Search to enter, there are four ways to download for users to choose.

　　

Take Beijing as an example, use the polygon file that was done before, and choose the Third way to download it.

Browse to the existing polygon and click OK. The polygon is loaded onto the DEM chart below, showing the need to download 6 shards.

　　

Click Next and a list of six files appears.

　　

Clicking Next will give the user the option to download the data.

　　

6, click Agree after download, separate download and bulk download.

　　

The speed is slow, only the first one is downloaded here, and the three-dimensional modeling is only demonstrated on this DEM.

Three-dimensional modeling

It's much easier to have DEM data for three-dimensional modeling. There are a lot of software to choose from, Arcscene for example. The steps are as follows:

In Arcscene, three-dimensional modeling data requires projected coordinates. So the first step is to set the projection for the data.

Load the data into the arcscene.

A three-dimensional effect is achieved by right-clicking on the data layer and setting it accordingly.

　　

The effect is as follows:

　　

Three-dimensional parts mainly provide basic ideas, to make a beautiful three-dimensional model also need to synthesize a variety of knowledge to render.

At this point, the "Google Earth and ArcGIS Data Interaction" series is complete, with a total of four.

Google Earth interacts with ArcGIS data (iv)