• find OES_texture_float dependency workaround
• max fragment uniforms below 64 to support iPhone

A lot of repeated code with glOperation="none". Make it more general to remove the current limit of 6 layers.

Currently transitions, hillshading and contours only work with glOperation="none".

The texture atlas used is currently quite large as it is also used to cache tiles for advanced hillshading. Find a better way to cache the tiles and the texture size can be reduced.

iOS does not support writing to float texture. Related to #29.

Currently using the 8 adjacent tiles to calculate advanced hillshading (3x3 grid). The shadows could stretch more than a tile away which would create artifacts. Ways to address this:

• Add option for using larger (5x5) grid to calculate hillshading. Advanced hillshading is already a heavy operation and this would make it much heavier.
• Raise the light source so the shadows do not stretch that far

Can get some weird artifacts if a new updateOptions is sent during a transition. Wait for transition to finish or abort before using new options?

Hi there,

I've got your library going on the https://hirdsexplorer.nz/ website, and it's worked quite well so far.

I'd like to be able to update the colormap after every scroll event, so that it spans from the lowest to the highest values that are currently visible, to allow the user to see the spatial variation in that particular area. This is a common feature in GIS software packages. At the moment I use a global minimum and maximum on each colormap, and the maximum is dictated by the mountains.

Is this a feature that you would be willing to have in your library?

I would be willing to help in some way, but I'm not sure how. I've had a look in src/shaders/index.ts to see how pixel values are calculated, but it seems to me the challenge will be in working out which parts of each tile is visible at any one time. Do you have any ideas on how it could be done?

Thanks, Cameron

Hi,

Thanks for this excellent plugin.

I have a single-band GeoTIFF file for elevation data. Would it be possible to fetch the file locally and get it to work with your module?
Please excuse my inexperience in this but I can't figure it out myself or if it is already possible with tileFormat = dem .

My thinking is to have the option for arraybuffer instead of url and/or tileFormat = tiff then modify the code for _fetchTileData to handle either arraybuffer directly or process through geotiff.js library like below.

              fetch("file.tif")
              .then(function (response) {
                return response.arrayBuffer();
              })
              .then(function (arrayBuffer) {
  		return GeoTIFF.fromArrayBuffer(arrayBuffer);
              })
              .then(function (tiff) {
                	return tiff.getImage();
              })
              .then(function (image) {
                	const width = image.getWidth();
                	const height = image.getHeight();
                	const extent = image.getBoundingBox();
                	const raster = image.readRasters();
                	const rgbImage = image.readRGB();
              })

Sorry about the code but I'm just listing the different values to get from geotiff.js.

Also, I found this code in here that can handle tiff files with an example file if it can be of help.

To reduce number of fragment uniforms send the colormap as a texture

Hi there,

Thanks for your module--I'm having a go at using in a project at the moment.

Your wiki page on tiles has a comment about Float32 tiles that says "Given access to the binary pixel data, producing these tiles is trivial. We just take a buffer full of 32-bit floats and hand that over to a PNG encoder, which assumes it's getting RGBA pixels." It may be trivial if you know how, but I don't and I'm definitely struggling!

I have a geotiff file of float32 data. I've written a Python script to convert this to 4 channels of integers, and then use gdal2tiles to convert it to tiles. The problem is that the data ends up all corrupted: instead of being read as values between 75 and 950 it's being read as -2.318841646091599e+38 and similar. I'm sure it's the Python script that's the problem. Can you give me some guidance on where I might be going wrong? And with respect to your package, it would be great if you could improve your documentation to explain to new users how to do that conversion process (eg with some sample code). I'm sure I'm not the only one who would find this process difficult.

If it helps to know, I'm using macOS.

Python (3.8):

import numpy as np
import rasterio

# Convert tiff with 1 channel of 32-bit floats to a file with 4 channels of
# 8-bit integers
with rasterio.open('example_input_file.tif') as src:
    floats = src.read()
    floats[floats==src.nodata]=0 # replace 'nodata' value with zero, as all
        # data values will be greater than zero
    print("Max",floats.max())
    print("Min",np.min(floats[np.nonzero(floats)]))

    treated_as_ints = np.zeros((4, floats.shape[1], floats.shape[2]))
    for channel in floats:
        for i, row in enumerate(channel):
            for j, cell in enumerate(row):
                a,b,c,d = np.frombuffer(cell, dtype=np.uint8)
                treated_as_ints[0][i][j] = a
                treated_as_ints[1][i][j] = b
                treated_as_ints[2][i][j] = c
                treated_as_ints[3][i][j] = d

    # Write to a new 4-channel 8-bit file.
    profile = src.profile
    profile.update(dtype=rasterio.uint8, count=4, compress='lzw', nodata=0)
    with rasterio.open('example_output_file.tif', 'w', **profile) as dst:
        dst.write(treated_as_ints.astype(rasterio.uint8))

gdal2tiles script:

gdal2tiles.py --xyz -w 'leaflet' -z '5' -s 'EPSG:27200' 'example_output_file.tif' tiles

Fallback to (un)packing float->rgba if not