Too narrow or too wide?

[SAR704]

This UTM overlay is easy to make out, and has reasonable, but not outstanding detail.

I did ask this before, and the response was to do with the route filter or something. I changed it to 8 tiles, and it's still barely 100 metres wide. I need it to be at least 700 metres wide, if not larger.



It seems like the higher the resolution the UTMs are, the narrower they get.

I must have done something wrong. But there looks to be two route filter check boxes. One via the DEM export option, and one associated with the UTM export option. I literally have no idea as to which one is relevant, as I'm still trying to make sense of this program, as I have been for the last 6 months.

I need the tiles to cover all areas near the track. Any ideas?

[geophil]

I need more information here. How does it look in the TransDEM main window? Rectangular mask and route set? And what are the UTM tile export dialog settings?

[SAR704]

I have no idea what you mean re regular mask. But this is what it looks like:



I am looking to get at least 5kms of UTMs with zoom level at about 19 or 20, for the area from Adelaide yard to somewhere near Goodwood to start with.

I need them as high definition as possible, whilst encompassing a catchment area that is at least about 2kms wide from left to right (assuming the track is dead centre). Been struggling with it for months. Now that I've switched to TRS22, the tiles are less out of wack, and more consistent. I haven't adjusted any KUID settings since the change.

Is it possible to achieve a very close zoom level, whilst having the UTMs at at least 1-2kms wide?

I have read the manual several times. I am perplexed as to how 'overlap' interacts with max rel point dist. I did look it up. But it was tricky for me to interpret. I have G 0gle Maps (key) enabled, orthopohto, width height 512 pixels, zoom level at 19, with zoom max (bar to the immediate left) at 10, overlap at 25, max rel point dist at 50.

I am under the impression that the closer one is zoomed in, the narrower the UTMS get. Is this the reality? If so, it makes it impractical to model this route for me. Because I am very dependent on aerial imagery.

[geophil]

So, the issue is on the geo data acquisition side, not the Trainz export side. Keep in mind that these two parts are completely independent of each other.

And you are right, the larger the scale, the "smaller" the map tile (Also referred to as tile map in digital cartography).

Again, not to be confused with the UTM tile as an asset for Trainz. A Trainz UTM tile is always either 1000x1000m is size or 4 times 500x500m. Its size in pixels varies and depends on the scale of the geo data content.

The map tile on the other hand, acquired from some geo map tile provider on the internet, is always 256x256 pixels. TransDEM can combine those tiles to a maximum of 4096x4096 pixels. However, spatial extent of such a tile, its physical size in metres, depends on scale. A larger scale needs more pixels to represent the detail. Accordingly the size in metres for a tile shrinks.

You acquire the map tile along a given path, polylines typically created with the build-in simple route editor. There is no option to laterally extend this path, though. To obtain more map tiles to the right and left of your route, you add additional polylines to your path. The easiest way to do that is to duplicate the polyline in the route editor (Ctrl + LMB) and move them to a suitable parallel distance. May require a bit of experimenting.

[SAR704]

Thanks for the summary Roland. I never once thought of duplicating the polylines.

The downside is the time it takes to render the tiles with 10 times the amount of data requested. But I did lower the tile res to 512 from 2048 pixels. So hopefully it shows something. It's basic logic. But it almost always eludes someone like me unfortunately.

[geophil]

But I did lower the tile res to 512 from 2048 pixels.

You are not referring to the setting in the map tile client? Because that's size in pixels, not resolution. In its minimum setting of 512, it combines 2x2 tiles of the standard 256px size, in its max setting of 4096 it combines 16x16 256px tiles. Bigger size means simpler path. Scale here is solely set by zoom level.

[SAR704]

I'm referring to 'Map size - Width and height'. There are options from 512 pixels to 2048 pixels. I'm a little perplexed as to what difference it makes. With it set at the 2048 value, it seems to take 4 times as long at the very least.

[geophil]

Sorry, the max is 2048, not 4096. That's 8x8 256 pixel tiles = 64 tiles for the map clipping. With 512, it's only 2x2 = 4 256 pixel tiles. The larger setting gets you a larger image. As the scale remains the same, the larger image will cover a larger area. And, of course, the amount of data to be transferred also increases. Depending on your internet connection speed and on server load on the provider side, it will take noticeably longer to transfer. On the other hand, you need fewer clippings in total.

Test this for yourself. Load some DEM. And the add a single map tile clipping, first with the 512 pixel size setting, and after that with 2048 pixel sitze, for the same spot. You will notice how mach larger the map area will become. And that will save you on necessary parallel polylines when acquiring map images along a path.

[SAR704]

Also wanted to ask. Is there any way to expand the coverage using the 'overlap' and 'max rel point dist' values?

I have read the manual. But it doesn't always provide a direct answer to a query I have in mind.

And also, I enabled a route filter of 18 tiles. All of a sudden in spite of several parallel lines drawn in TransDEM, the UTMs are now conveniently about 50 metres wide. Which is about 60 times less than what's desirable.

I am absolutely clueless as to what the route filter within the UTM generation field actually refers to. I know it's probably in the manual. But I tend to find a written explanation to be easier to interpret.

It gets tiring when one stagnates for literally 5 months, due to the 10 year learning curve for this program, that only applies to folks like me, who are slightly challenged cognitively.

[geophil]

Also wanted to ask. Is there any way to expand the coverage using the 'overlap' and 'max rel point dist' values?

Leave these at their default settings. They control the number of map clippings deemed necessary to cover the path.

All of a sudden in spite of several parallel lines drawn in TransDEM, the UTMs are now conveniently about 50 metres wide. Which is about 60 times less than what's desirable.

You said, you reduced tile size from 2048 to 512 pixels, making them smaller. Not a good idea, as I said in my previous postings.

I am absolutely clueless as to what the route filter within the UTM generation field actually refers to.

Export to Trainz only. If there is no data source for that, it doesn't have much of an effect.

UTM tiles are specific to the Trainz exporter in TransDEM. They do not affect any method of geo data acquisition. Again, UTM tiles and map tiles (or tile maps) are two different, completely independent concepts!