Production technology of digital line drawing

The original data mainly include: field data collection, aerial photos, high-resolution satellite photos, topographic maps, etc. Production method:

1) digital photogrammetry and three-dimensional tracking stereo mapping. At present, the domestic digital photogrammetry software VirtuoZo system and JX-4C DPW system all have corresponding vector graph systems, with high accuracy. Among them, VirtuoZo system has workstation version and NT version, while JX-4C DPW system has only one NT version.

2) Analytical or computer-aided digital mapping. This method is to obtain DLG data by mapping aerial photos and high-resolution satellite photos on an analytical plotter or simulator. In this way, it is necessary to use graphic processing software such as GIS or CAD to edit the obtained data and finally produce the result data.

3) Scan the existing topographic map and vectorize its elements through human-computer interaction. At present, vectorization software, GIS and CAD software commonly used at home and abroad use vectorization function to vectorize scanned images and then transmit them to corresponding systems.

4) Digitize the elements of manual tracking framework on the newly-made digital orthophoto map. Screen tracking: You can use CAD or GIS and VirtuoZo software to insert the orthophoto map into the workspace according to a certain proportion, and then collect the corresponding elements on the map.

5) Field survey map. (See the basic flow chapter of digital mapping)