CGCS2000 Coordinate System Projection Transformation Tutorial
Note: To convert the projection into the cgcs2000 coordinate system, you need to download the satellite image without offset for conversion. The conversion with offset will cause the converted satellite image to be distorted, the coordinates are wrong, and the registration cannot be performed.
Step 1: Select the no-offset map source and download the satellite images you need.
Step 2: Select the toolbar on the right side of the BIGEMAP software, and select [Projection Conversion], as shown in the following figure:
2.1 Selection Description:
1. Source file: Select the downloaded satellite image file (the file with the suffix tiff in the download directory)
2. Source coordinate system: the projected coordinate system of the opened source file (automatically read, no need to fill in manually)
3. Output file: select the file path and file name of the file you want to keep after conversion
4. Target coordinate system: Select the target coordinate system you want to convert to, as shown below:
Select More from the above image, as shown in the following image:
1: Select -CGCS2000 2: Select the region 3: Select the band number corresponding to the graduation band (usually default, can also be manually modified)
Select the corresponding division zone or central meridian (please refer to: How to select the division zone ?), click [OK]
5. Resampling algorithm: Projection conversion needs to rearrange the pixels of the image. The efficiency of each algorithm is different at a time. Generally, [cubic convolution sampling] is selected to achieve the best effect. As shown below:
6. Specify the transformation parameters: If you don't know, you can leave this information blank. If √ is on, it will be as shown below:
This parameter is [three parameters] or [ seven parameters ], which are all national secret parameters. You need to go to the local surveying and mapping department or land department to sign a non-disclosure agreement in the name of the unit to purchase. This parameter varies from place to place and is strictly confidential. Please do not circulate freely.
Step 3: Click [OK] to start the conversion, as shown below:
Step 4: When done, open the output folder you just selected, which will contain the converted satellite images.
Step 5: If you need to fit the vector files you already have, please refer to: [ BIGEMAP Image Overlay Registration without Offset ]