Change camera parameters in the grammar to have meaningful values

[GMMULLER]

This is how the camera is currently specified in the grammar:

"camera": {
                    "position": [
                        -9753739,
                        5117375.5,
                        2216.08675
                    ],
                    "direction": {
                        "right": [
                            14146.2158203125,
                            100883.421875,
                            2216086.75
                        ],
                        "lookAt": [
                            14146.2158203125,
                            100883.421875,
                            2213086.75
                        ],
                        "up": [
                            0,
                            1,
                            0
                        ]
                    }
                }

Even though that is the parameters used internally they should be exposed in a more friendly way to the user. One way to do that, for example, is using lat/long (EPSG:4326) instead of EPSG:3395 for the camera position. Internally the system still manipulates 3395

[sajal1123]

I can look into this. Would you like to change the EPSG for the entire project, or just the grammar(and convert it to EPSG:3395 for internal manipulation)?

[sajal1123]

Hi @GMMULLER, if we add a coordinate conversion from EPSG:4326 to EPSG:3395 in ../dataLoading/data.py, will it work?

[GMMULLER]

Hey Sajal, sorry for the late reply I didn't see the notification. The idea is to change the EPSG just for the grammar and convert it to 3395 for internal manipulation. I'm not sure if I understand what you mean by adding the conversion to data.py. There are two flows of data: (1) the user changes the grammar (2) the grammar is automatically changed by the "link" functionality. Both changes will probably involve GrammarPanel.tsx. But (1) is 4326 to 3395 and (2) is 3395 to 4326. On the end of the day camera.tsx has to receive 3395 and the user see 4326.

[sajal1123]

I see, by "adding a conversion" I meant inserting a function that converts the EPSG to/from 3395.

I'm currently going over the logic flow in GrammarPanel.tsx file, it looks like we can convert the EPSG from the user friendly format to 3395 in applyGrammar.

Also, did you mean camera.ts at the end?

[GMMULLER]

Yep, that is probably the way to go. Sorry I meant camera.ts haha

[sajal1123]

Hi @GMMULLER, since the 4326 coordinate system will have only the x and y coordinates, how should the value for the z-coordinate be assigned after converting the input to 3395?

[GMMULLER]

So the z coordinate is not considered in the conversion. It is in meters so you can just attach it to the output. If the input is (x,y,z) the output will be (x',y',z)