How should I overlay a grid on a LeafletJs Map? - leaflet

I have a LeafletJs Map with a Lat / Lon graticule. However what I would like at this point is to overlay a grid on the map with a fixed number of rows & columns (say, 19 rows and 17 columns), where the little rectangles that make up the grid would not change size as I zoom in and out on the map. How would I do that?

There is a Leaflet plugin called leaflet-virtual-grid (based on L.Grid) which does what you want. The provided examples need a few fixes to work, here is the result.
I didn't see any option to make the x and y length different.

Related

Spacing between heatmap point

I tried to customise leaflet heatmap.js to render rectangles to generate a heatmap. I was doing good so far. But, there are spacing in between rectangles that I can't get rid of. As in the picture.
heatmap
Solutions that I tried: turn off antialiasing, add offset. While adding offset remove the space, it creates an area with "blended color" which I don't want to have. I wonder if there is a solution to remove the gap or remove the blending color in heatmap.js.
Thanks and regards.
Turn out it is precision problem of the leaflet latlong to screen coordinate function. I have fixed it by recalculate the coordinate.

Setting the CRS for non-geographical svg map

I'm trying to show a custom non-geographical map with CRS.simple as explained here:
In a CRS.Simple, one horizontal map unit is mapped to one horizontal
pixel, and idem with vertical
However, I wish to use an SVG vector image as an overlay, but I don't get how the map unit is decided in this case, since the vector images don't really have a resolution?
Also, how could set the CRS origin's location to a specific point?
Thanks for helping

Z Offset for Mapbox labels

I have a 5-floor indoor building on top of a Streets Style map in Mapbox Studio Style editor. It looks almost ok in 3D, all extruded poygons and lines are at the right base height and height with about 3m space betwee the floors.
But I cannot find any base hieght or z-offset option for Symbol types in order to show labels correctly at the place where they should be in 3D. Is there a z offset for labels at all?
It's not currently possible, but has been discussed as a possible enhancement: https://github.com/mapbox/mapbox-gl-js/issues/3993

Is there a way to check for markers whos icons intersect / overlap visibly?

I am building a map and want to use the leaflet markercluster plugin to cluster any markers that intersect visibly (the icons overlap each other). I can't seem to figure out a way to check whether the markers icons intersect though.
I've examined the documentation and the Marker objects. The marker object has no "bounds" object and has no function to return the bounds of the icon.
Yes, it's possible.
This is implemented in some Leaflet plugins, like Leaflet.LayerGroup.Collision - the technique involves fetching the computed style of each icon's HTML element to get the actual size in CSS pixels, offset those numbers by the relative pixel position of the marker's LatLng, and using a rtree data structure to speed up the calculation of the overlaps. Do have a look at the complete source for LayerGroup.Collision plugin.
Note that this technique only takes into account the rectangular bounding boxes of the icons; while it would be possible to check for the individual transparent pixels, that would involve more complex data structures and a different technique to fetch the opacity of each pixel.

Sigmaplot: How to scale x-axis for correctly displaying boxplots

I want to display overlapping boxplots using Sigmaplot 12. When I choose the scale for the x-axis as linear then the boxes do indeed overlap but are much too thin. See figure below. Of course they should be much wider.
When I choose the scale of the x-axis to be "category", then the boxes have the right width, but are arranged along each single x-value.
I want the position as in figure 1 and the width as in figure 2. I tried to resize the box in figure 1 but when I choose 100% in "bar width" than it still looks like Figure 1.
many thanks!
okay, I found the answer myself. In Sigmaplot, there is often the need to prepare "style"-columns, for example if you want to color your barcharts, you need a column that holds the specific color names.
For my boxplot example I needed a column that has the values for "width". These had to be quite large (2000) in order to have an effect. Why ? I have no idea. First I thought it would be because of the latitude values and that the program interprets the point as "1.000"s, but when I changed to values without decimals, it didnĀ“t get better.
Well, here is the result in color.
Have fun !