What kind of products are needed to support the basic data for making digital orthophoto maps?

The production of digital orthophoto map needs the support of basic data, which generally includes the following contents:

1. High-precision terrain data (DEM/DTM): The production of digital orthophoto map requires high-precision terrain data, including digital elevation model (DEM) and digital terrain model (DTM), which can be obtained by global positioning system (GPS) or lidar.

2. Aerial image data: The production of digital orthophoto map needs aerial image data with high resolution and precision. These data can be obtained by aerial remote sensing or satellite remote sensing, including aerial images and satellite images.

3. Ground control point data: Ground control point data refers to some known coordinate points needed in image processing for image positioning, correction and registration. These points can be obtained by GPS survey, ground survey and so on.

4. Other auxiliary data: including geographic information data such as administrative divisions, highways, water systems and topography, which can be used for the classification and labeling of digital orthophoto maps.

Data acquisition method of digital orthophoto map

1. aerial photography: aerial photography is the image data obtained by shooting with airplanes (such as airplanes and helicopters) and processing on the ground. Aerial photography can provide high spatial resolution and ground resolution, which is suitable for the acquisition of small and medium-sized objects.

2. Satellite remote sensing: Satellite remote sensing is a technology that photographs, records and transmits data on the earth's surface through satellites. Satellite remote sensing can obtain large-scale and large-scale image data, which is suitable for large-scale monitoring and analysis of the earth's surface.

3. UAV remote sensing: UAV remote sensing is the use of drones for aerial photography to obtain high-resolution image data. Unmanned aerial vehicle (UAV) remote sensing has the advantages of flexibility and low cost, and is suitable for small-scale and high-precision ground object acquisition.

4. Public data: Many countries and regions provide digital orthophotomap public data free of charge. For example, the USGS in the United States, Copernicus in Europe, the National Basic Geographic Information Center in China and other institutions have provided the download of digital orthophotomap data.