How to change size of grid

[mcp292]

MWE

import altair as alt
import numpy as np
import pandas as pd


x = np.arange(100)
source = pd.DataFrame({
  'x': x,
  'f(x)': np.sin(x / 5)
})

alt.Chart(source).mark_line().encode(
    x=alt.X('x').axis(tickMinStep=1),
    y=alt.Y('f(x)').axis(tickMinStep=1)
).save("grid_step.png")

alt.Chart(source).mark_line().encode(
    x=alt.X('x').axis(tickCount=100),
    y=alt.Y('f(x)').axis(tickCount=100)
).save("grid_count.png")

Problem

I would like to make a grid line appear at every single unit.

When using tickMinStep=1 nothing happens:

But the documentation makes it seem this is exactly what I want:

The minimum desired step between axis ticks, in terms of scale domain values. For example, a value of 1 indicates that ticks should not be less than 1 unit apart. If tickMinStep is specified, the tickCount value will be adjusted, if necessary, to enforce the minimum step value.

Using tickCount seems to work, but requires that you know the bounds of your data a priori:

Notes

I would prefer to use tickMinStep or similar because I would like to specify the interval/spacing of the gridlines, without knowing the domain min and max.

This answer might be related, but I don't know how to translate it: vega/vega#583 (comment).

[ChristopherDavisUCI]

What I’m suggesting feels hacky, but what if you specify both a large tickCount (like 1000) and tickMinStep=1. Does that produce what you want? I think you are hoping for a tickMaxStep rather than a tickMinStep, but it doesn’t seem to exist.

…

On Tue, Aug 15, 2023 at 10:04 PM mcp292 ***@***.***> wrote: MWE <https://urldefense.com/v3/__https://altair-viz.github.io/gallery/simple_line_chart.html__;!!CzAuKJ42GuquVTTmVmPViYEvSg!JbLjcBDn-cSdWqI0Oo7AZewM8V12w-od-XOrHtP8Sscu_dSYr5_1YhuNwHJjUsUq_JQsBKEgwZU563lrK5lVI6Q$> import altair as altimport numpy as npimport pandas as pd x = np.arange(100)source = pd.DataFrame({ 'x': x, 'f(x)': np.sin(x / 5) }) alt.Chart(source).mark_line().encode( x=alt.X('x').axis(tickMinStep=1), y=alt.Y('f(x)').axis(tickMinStep=1) ).save("grid_step.png") alt.Chart(source).mark_line().encode( x=alt.X('x').axis(tickCount=100), y=alt.Y('f(x)').axis(tickCount=100) ).save("grid_count.png") Problem I would like to make a grid line appear at every single unit. When using tickMinStep=1 nothing happens: [image: step] <https://urldefense.com/v3/__https://user-images.githubusercontent.com/49123398/260827081-45afb8ec-60e7-45c4-8f1f-108865f69ace.png__;!!CzAuKJ42GuquVTTmVmPViYEvSg!JbLjcBDn-cSdWqI0Oo7AZewM8V12w-od-XOrHtP8Sscu_dSYr5_1YhuNwHJjUsUq_JQsBKEgwZU563lrAa_Rolw$> But the documentation <https://urldefense.com/v3/__https://altair-viz.github.io/user_guide/generated/core/altair.Axis.html__;!!CzAuKJ42GuquVTTmVmPViYEvSg!JbLjcBDn-cSdWqI0Oo7AZewM8V12w-od-XOrHtP8Sscu_dSYr5_1YhuNwHJjUsUq_JQsBKEgwZU563lrYBt2NHA$> makes it seem this is exactly what I want: The minimum desired step between axis ticks, in terms of scale domain values. For example, a value of 1 indicates that ticks should not be less than 1 unit apart. If tickMinStep is specified, the tickCount value will be adjusted, if necessary, to enforce the minimum step value. Using tickCount seems to work, but requires that you know the bounds of your data a priori: [image: count] <https://urldefense.com/v3/__https://user-images.githubusercontent.com/49123398/260827161-89630d84-b1c3-4a26-a0f8-c3db6b96d984.png__;!!CzAuKJ42GuquVTTmVmPViYEvSg!JbLjcBDn-cSdWqI0Oo7AZewM8V12w-od-XOrHtP8Sscu_dSYr5_1YhuNwHJjUsUq_JQsBKEgwZU563lrl2aZ5C4$> Notes I would prefer to use tickMinStep or similar because I would like to specify the interval/spacing of the gridlines, without knowing the domain min and maxs. This answer might be related, but I don't know how to translate it: vega/vega#583 (comment) <https://urldefense.com/v3/__https://github.com/vega/vega/issues/583*issuecomment-322338211__;Iw!!CzAuKJ42GuquVTTmVmPViYEvSg!JbLjcBDn-cSdWqI0Oo7AZewM8V12w-od-XOrHtP8Sscu_dSYr5_1YhuNwHJjUsUq_JQsBKEgwZU563lrQwi4Bcw$> . — Reply to this email directly, view it on GitHub <https://urldefense.com/v3/__https://github.com/altair-viz/altair/discussions/3153__;!!CzAuKJ42GuquVTTmVmPViYEvSg!JbLjcBDn-cSdWqI0Oo7AZewM8V12w-od-XOrHtP8Sscu_dSYr5_1YhuNwHJjUsUq_JQsBKEgwZU563lrCJoc_mM$>, or unsubscribe <https://urldefense.com/v3/__https://github.com/notifications/unsubscribe-auth/ATXKWIFEIUOS5FH2ZKRBYY3XVPI3JANCNFSM6AAAAAA3RQT7IQ__;!!CzAuKJ42GuquVTTmVmPViYEvSg!JbLjcBDn-cSdWqI0Oo7AZewM8V12w-od-XOrHtP8Sscu_dSYr5_1YhuNwHJjUsUq_JQsBKEgwZU563lrGCzjuWg$> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[mcp292]

I agree, tickMaxStep is actually what I need. That does feel hacky, I wouldn't move forward with that.

[rambip]

@mcp292 I agree with you.

If you still think this is an important missing feature, maybe try to defend it over there: vega/vega-lite#9594