Using dc.rasterLayer to draw lines


#1

Hi guys,

Currently, I need to use the function of dc.rasterLayer(“lines”) to draw lines on the map.

But is there any documentation that I can refer to? Now I just see the example of drawing points on the map in the github of mapd-charting. I really have no idea how to apply it to lines.

Thanks!


#2

Hi @Jason
OmniSci will support the rendering of LINESTRING objects on a geographic map in a soon to be released version of Immerse.
There is sample code for rendering LINESTRING using VEGA spec in this repo.

Regards,
Veda


#3

Hi @veda.shankar,

I’m developing an application now, so I need to build some custom functionality instead of just using Mapd Immerse.

Because I need to do the cross filtering like, between LINESTRING and time chart, and it seems that VEGA does not support the cross filtering, so I need to use mapdc.js.

I have checked the source code of mapdc.js and found that it supports drawing lines on a map using the raster chart, but I can’t find any detailed documentation about how to use it. Therefore, I am wondering if you can give me quick tutorial to this.

Thanks a lot


#4

Hi @Jason

I spoke with the developer, and we will update GitHub mapd-charting with an example on rendering LINESTRING object by next week.

Regards,
Veda


#5

Hi @veda.shankar,

That would be great. Big thank to your help!

Best regards,
Jason


#6

Hi @veda.shankar,

I just saw the update of the example on rendering LINESTRING object on Github mapd-charting, thanks for that.

BTW, I have seen your documentation on how to use VEGA, I think that is well written and comprehensive. However, I am wondering whether there are similar documentation with regarding to mapdc.js so that developer can refer to them soundly.

Regards,
Jason


#7

Hi @Jason,
I was going to notify you today that Linemap example has landed in mapd-charting repo, but you are ahead of me :slight_smile: I will check on the documentation.

Regards,
Veda


#8

Hi @veda.shankar,

I am just wondering whether there is any progress on the documentation?

Actually I have seen the documentation about mapdc, here is the link: https://omnisci.github.io/mapd-charting/docs/
However, you can see there is nothing about raster chart, which is needed to draw lines or points on the map. Looking forward to your help!

regards,
Jason


#9

Hi @Jason,

Yes, the docs need updating, looking into it.

Regards,
Veda


#10

Hi veda.shankar,

There is a server issue concerning about the linemap example.
https://omnisci.github.io/mapd-charting/example/exampleLinemap.html

Moreover, when I applied the code in the linemap example mentioned above, there was an error and I didn’t know how to deal with it, here is the screenshot:

image

Actually I think the line map is a crucial component of the geospatial visualization, so can you guys quickly fix this problem. It is been a month since I proposed this issue.

Best regards,
Jason


#11

Hi @Jason,

Sorry about the delay, I will discuss with the engineer and get back to you.

Regards,
Veda


#12

Hi @Jason,

Can you share the DDL of the table and also select a couple of rows of the data with the linestring data to help debug the issue.

Regards,
Veda


#13

Hi @veda.shankar.

Thanks for your reply.

Sure. Here is the screenshot of the structure of the table:
image

Screenshot of selection of rows:
image


#14

Hi @Jason,

I confirmed that the Linemap example (exampleLinemap.html) is working fine if you:

Regards,
Veda


#15

Hi @veda.shankar,

Thanks for your reply. I have updated the mapd-charting library and the OmniSci server. The good thing is that the previous error disappeared. However, there is still another error message. Here is the screenshot.

image

Regards,
Jason


#16

Hi @Jason

When I launch the app, the linestrings are rendered and there is no error. However, as soon as I zoom in I see the error:

Uncaught ReferenceError: wktString is not defined

We are investigating …

Regards,
Veda


#17

Hi @veda.shankar

I am just wondering how is the progress, and the approximate time would it take to address it.

Best,
Jason


#18

Hi Jason,

The assigned engineer was traveling this week and the backup on PTO. I expect to see some progress next week.

Regards,
Veda


#19

Hi @veda,

Any progress this week?

Best,
Jason


#20

Hi @Jason,

Still waiting to hear back from engineering who are busy in a release cycle.

Sorry!
Veda