Precise SRTM .hgt file handling

And yes... I didn't use the right Resolution.

After you told me, that Locus uses the File-Size to "calculate" the Resolution, it was all clear. I have to use square resolutions in divided parts of 1arc second. Thank you much.

Hello Markus,

when you enable manual drawing that Locus should interpolate between the start/end points of the line for usage in Route planner. Usually, it should generate points every 100m. You see at the bottom chart only straight line? You may even slide up the bottom chart and then move with start/end point to see changes in the chart immediately! let me know if this works for you.

OK, I tested it. And YES, much better. I tested it by making a manual Route uphill out of a quarry. Let me describe: its a hole where are roads around in circle and Hill-upwards in steps.

And now i see the Steps of the Roads like in a real Cut of the Terrain. Just because of the limitation to 5m i sometimes don´t see one of the road-steps. (I need to play around with the 2nd Route point so that the Interpolation hits also this road)

So is there a reason why the minimum Value is limited to 5 m ?

I think its an Option, because allways changeable back to 5m or 100m.

If you give me the option to go down to 1 m interpolation, I try to make even better height Model of my Region.

At the moment i have about 3m stepping model, OK, locus is a little bit slower in panning around (when Hillshade is turned on), but i also switch off Hillshading sometimes, because i use LoMaps overlayed by a Grayscale-Hillshade-Map (more steep = more dark). As Overlay Method I use Multiply or Darken. So I normally don´t need the Hillshade Option in my Region. And Locus is really fast in overlaying this 2 maps. Panning and zooming is so REALLY FAST.

I need the .hgt data just for getting good Profiles and for measuring Height differences exactly. My Basis-Data is normally 30 cm exact in height. (75% of all the points, most of other points are 50cm exact)

At all now Locus is really close to be GREAT for my Task. Thank you really much for this Tool.

Because I want to show Friends in the Mountain-Rescue-Team what Great Maps are possible today, I have sometimes special tasks. But now most of them are done great.

(Now we see where to get out best, where is a possible route in Offroad-Terrain,...)

Hello Markus,

glad we have some progress. I choose 5 meters limit as the compromise and also some kind of security mechanism. The too low number may cause slow-down (in real-time interpolation when you move with one line point in Route planner), so I wanted to prevent setting of too low number. Anyway ok, let's try it to next version with the 1m option.

I'm surprised to read about elevation data with such huge accuracy mainly in mountains. Anyway, I'm always glad to read that Locus Map seems to be a helpful companion in useful professions.

Hello

OK, Now i get really realistic profiles. I attached some Screenshots. And its also very good to get fast access to switch overlay on or off, to switch Hillshade on and off,... Yes Locus is really Good for my tasks.

Hm... Just some little thing is...

Ok, when there is a Road and i plan an automatically Route with Walking-Profile, i get a Height-Profile and its also the same when i open the saved route-details and go to diagramm (profile)

BUT not when i save my mannually planned route. When go to details and profile, i get just the profile of my manally set route Points.

My Idea was first: if the 1m thing works well... why don´t we make it one step ahead.. and make the interpolation density dependable on the x-Axis zoom of the Height-Profile screen. (so interactively get the data from background .hgt data).

So that we get really more detailled when zooming in the x-axis. and less detailled when zooming out. So the problems with too much points is also solved. Maybe change the new option in Expert-Mode-Settings to a Factor-Variable, so with this factor we can choose the relation between x-Axis and interpolation-density.

Why is it working well in a automatically calculatet Route-Profile ?

But not in manually created.

Maybe you can helpe me with this also.

Hi Markus,

in case of the automatically computed route, the route itself is made from many trackpoints which are then also visible on the chart. So there is no interpolation between points. In case of manually draw route, in the final route are really saved only manually defined shaping points and interpolation we talked about before, is lost.

I had a similar request on old forum a few days ago, related to applying correct line style also to these manually drawn lines, which is the exact same problem.

Saving manually draw segments interpolated with 1 m is little overkill for huge lines. Understand your use case and agree that what you see in the route planner should be visible in saved track as well. I'm just not sure how to simply technically do it. Because it is more complicated to do and because it currently has a low priority, I'm sorry for now, but can't help here now.

ok, I think when going to route-details and to profile Page, there decide if its a Route or a recorded Track. (or in other words, if the route have recorded height-data or not). If its a Route without recorded height Data, then lets say get 800 height-Points of the whole "Route" and display it in the Diagramm. If you zoom in: then also take 800points but just of the visible Part of the Route (visible on Diagram x-Axis). So we get more detailled while zooming in. And Just if you export a Route to a Track, you can decide if you want to fill height data in or let it without height data. So its close to the thing when you analyze a segment of the Route. (Shift Start and End point along the Route while Zooming and Panning on the Height-Profile)

Just my ideas to this.

I think, the easiest way at Moment: Save all the interpolated Points. (Standard-Setting is to 100m, so no Problem)

Because: if i record a Track with Settings to 1m or 1s i also get much Points. And as you told, when planning a Route by any Kind of automatic Route-Calculation, locus also use many Points (all Points of the Road-Line ?).

I think it is no Problem to save also, for manually created routes, all interpolated Points for the Height-Profile. (Users can Always set the Interpolation-Step back to 100m or so)

One Other Question:

Can you add also a Parameter for "Heicht data multiplicator" as Standard set to 1.

My Problem: The height data Format is in 16-Bit integer values. So without making a Little "trick" my Software is just able to create Height-Grid in steps of 1m.

But, now i Exported my Data in "dm" Units. so i get 1000m instead of 100.0 m.

So Route-Calculated-Time is wrang and also other Parameters.

But if you add a factor to height-Data, then it will be perfect.

Thanks

Greets from Austria

Good day Markus,

give a try next beta version, it will be improved little bit and interpolated points will be saved in final generated route. We will see how this will work.

About your second request: sorry, but such special one-user options will only overcomplicate UI of app. Thanks for understanding.

ok, sure i understand. hm, i think its just a multiplication-facror of the height-data. if set to 1, there is not much cpu-extra load. And opens the possibility to use smooth height-data for everyone. In near future there will be available a worldwide high-precision height model.... ok, your argument for over-complication.

So thanks anyway. I can use 2 Files. 1 with Meters height data. (for standard use and for better time-calculation in routes) And one with deci-meter height-Values. (really smoothe display and smoothe %Uphill/%Downhill Graph)

Hello Menion

Thanks for adding this Parameter.

When I make a Manual-Route (Line of Sight) and i make shorter Route-Point distances than 100m, I don´t get the interpolated Height-Profile of this section.

But this is really neccessary, because when i plan a Manual Route i have often route-Point distances smaller than 100m, (And so no Interpolation between them)

So in the Software there is somewhere an additional Parameter which is fixed to 100m. (Minimum route Point distance for Interpolation)

Maybe you can set this Parameter equal to the "new" Parameter in Expert-Mode. (Interpolation-step)Reason: I think this can be same than route-Interpolation-step, because if someone wants tighter Interpolation steps, then the Minimum route-Point-distance also should be smaller.

At the Moment i Always have to make longer route Segments than 100m to get detailled Height-Profile. But in Terrain this is unusable. (I want to draw my Walking way down somewhere and get the height-Profile detailled)

Thanks

Hello Markus,

you are correct. Hard-coded 100m parameter found. Will be fixed in next version 3.37.1, thanks.

Hello

Yes it works perfect. so you have Meshed your data to a TIN? Then first thing is to export as .gmg file (greed) with cm as height units. And then you have to have also surrounding Data loaded in GlobalMapper. It can be tiles of SRTM. So for ecample, if you want to create a new N47E009 tile, then load your High resolution Data (can be any Area) inside N47E009. Then Load SRTM data of N47E009, N47E0010, N47E008, N46E008, N46E009, N46E0010. And also the 3 N48 tiles.

(Your High-Resolution Data Topmost)

Then click on File Export as Greeded Data, Select BIL.

Set your wished Resolution as Binary divided. So possible is 0,5" , 0,25" , 0.0125" , ... and so on.

AND exactly export a Region of N47 to N48, and E009 to E0010, (Exaxtly the Tile-Size of N47E009.) If posdible select Bicubic Interpolation.

I think you have to set the right projection first in Global Mapper. (Bevore u export to BIL, use the standard .hgt projection) If i remember right its Standard WGS84.

After this Process you (just) have high resolution Height-Data. So Locus can Show you the Height value and Hillshade.

But... for me much more important is to export the GlobalMapper Greeded Data to a Raster Map in .mbtiles format. Use in Globalmapper as Hillshade: Slope Shading. Set the Colors for 1° steepness to White and the Color for 89° steepness to a customized Gray-Tone. So that you get a Graytone Hillshade of your Height-Model.

Again use surrounding Height-Model to fill up missing Data to a Rectangle of any Size. Set your Projection in Globalmapper to the google Projection which is Standard for MBtiles format. EPSG:????

Then Export your High-Resolution Hillshade to the MBTiles Raster Map. (its like making a Screenshot of your actual Hillshade wiht actual Hillshade Settings)

After this you should have a perfect Raster Hillshade Map, which you can Overlay in Locus (Multiply) to each other selected Map. So Also to any OpenStreetMap.

LocusMap is much faster in overlaying a Raster Map (Multiply) than to produce a Hillshade.

This works perfectly if you have at least 5m resolution Height Data of your Region.

THX - working on it. Got some weird results, but will work more :)

i try to make a better help. Because i did asnswer without going to check. I plan to upload my created Files. And maybe i manage to make a Video about it.

Because i worked about 2 Month till i had the right Solution.

How dense is your Data. I mean the ground Resolution ?

In my Region i got Data with 1m and 0.5 meter ground resolution.. (points with Height values)

I did use the height Data without Trees (ground Points). This Data is calculated so that i see 1m thin walking ways also in forested Regions.

Yes, This Data provided by Sonny i use to Fill up surrounding to full Tiles. (Because Locus needs Fully filled Tiles)

But the data i use is much more dense. (1m or 0.5 m ground resolution)

1. Then i export my high density meshed model with cm as Height Unit. (no other resampling, bevore they have been in meters for height units) --> this results in much more Smooth Surface after export to .bil format.

2. I load Sonny´s Data for all Surroundings. AND also export them to "Global-Mapper Greed" with: cm height resolution. (can also be axported as one Tile or in Tiles)

3. Then i unload all Data and load the newly generated meshed Models. (My hires data and the Surroundings)

4. I then change the Workspace Projection to EPSG:4326 (=regular for .hgt files)

5. Then export whole Workspace to a .bil elevation data. There choose:

Elevation-Grid 2 Bytes (Signed)

Sample Spacing: 3.4722222222e-5 arc degree (= 0.125 arc Seconds)

Always generate Square Pixels

Resqampling: Bicubic interpolation

Vertical Units: Meters

Interpolate to fill small Gaps in Data

Motorola Byteorder !!!!

AND: as Export Bounds choose exactly a full Cell. (for example: to generate N47E009 export Bounds:

North: 48 ; West: 9

Sauth: 47 ; East: 10

Then you should get a .bil with Motorola Byteorder. This File can be renamed to N47E009.hgt and copied to SRTM Data in Locus folder.

This is just the 1st generated File. Now lets generate the more necessary Raster-Map from your Data....

Therefore let all data Loaded in Global Mapper and set Workspace-Projection to: EPSG 3857

Set the Hillshading to "Slope Shading" with White-Color at 1° and a custom made Gray-Tone at 89°

Then we are ready to export to .mbtiles Raster format. (Size of export Boundings as you wish)

upps did not see this part. Thx Michael and Markus. More stuff to look into - great :)

The hgt are working now. I did it like this:

Opened my geotiffs from the norwegian mapping authority in globel mapper. Reprojected ti Geographical Lat/Long in the configere menu under tools. Exported directly from there to BIL with the settings you recommended Markus. Works fine thx. Now on to the hill-shading

If i did so, i got "Steppy results". I did therefore first export to "cm" elevation units. (as global mapper Grid).

Then work with the "new" generated data and set in the Layer Options of the "new" File to Bicubic interpolation.

Then export to .bil File as i described.

This Step with setting the Bicubic Interpolation to Layer options to the Files is more significant if you export to .mbtiles Format, because its like making a Screenshot.

Did you also download the National Datasets ? If you klick on Download and select the Register ("National datasets") i find rich 1m DTM files. (DTM1 the 1m resolution).

And for filling up some missing spots i downloaded (DTM10, the 10m resolution of whole)

Yes, i also got stepped results, but only when trying to make the hillshade in global mapper, Not in the terrain model itself. So i tried to make the hillshade in golden Surfer, which seems to work better. I'm still not sure if i want this kind of hillshade, but i will try to evaluate it in very zoomed in cases...

My main aim is the elevation data to be precise, because , as i understand Menion, the next version of Locus will also give us the inclination between two points or between position and cursor. And to use that for avalanche assessment it is crucial that the elevation date is precise enough...

My maps (home made) allready are loaded with slope color shading to mark any terrain between 20 and 90 degress steepnes.

Tried to attach a file - dunno if its working. But there you can see the border between the 1m and 10m resolution as a brown line (because this is where the 1m model ands and "drops down to 0 meters). Brown is the color shading for steeper than 55...

Link to map: https://drive.google.com/file/d/1g2-bcayNA4DzB-X3sNBeKcWGso5keV2z/view?usp=sharing

Its funny though. Norwegian mapping really kept their data very pricy a long time after the EU had decided they should be free. But after 10 years or mor with legal threats the Mapping Authority caved in, but then announced it as a voulantary gift to the people. But mapp quality and availability have been booming since data was freed, and it shows out to be of huge public benefit to free data like that. And in a year or two we will have terrain model of every tree and every stone og drop or whatever feature that is either part off the terrain or on the terrain

I did make the Hillshade with Slope-Shading because if i Shade in any direction, i get "Shadows" in regions where are not so steep. And i can´t see some Details anymore.

With Slope-Shading in Graytones from White = 1° to Graytone (82 away from Black) i get a Hillshade which is just Dark in Steep Areas, and exactly this i want to have. (Where is it difficult to get down... )

I did choose 0.125 Arc Seconds as Resolution because its close to 3m Ground resolution. Thats enough for Elevation and Hillshade Data. (Locus is handling it good)

I just use this for what it is, Elevation-Data at cursor Position. (And sometimes as additionally Hillshade)

And that i get Profiles of line of Sight. (Terrain-Cut)

But if u try to Hillshade the 1m Data in Global-Mapper with Slope-Shading (1° White, 89° Dark-Gray),

and zoom in to where are ways in forested region, or Waterways going below some ways, you will find out, that you see really rich details of Terrain. (You can measure how wide a Road is, to see if its driveable by a car)

And exactly this view i wanted to get on LocusMap, and i got sucess with generating 0.5m/Pixel Raster Maps.

(yes in meters because Projection for .mbtiles is the (google) pseudo mercator) 0.5m/Pixel keeps nearby all details of 1m Height data.

And sure, the Trick is to overlay this Data to a LoMap (osm-Map) by Multiplication in LocusMap. (You can also try to Overlay Multiplicate "OpenStreepMap (basic)" in GlobalMapper, (you will get a good view of Map + Hillshade)

Greets from Austria (And yes i want to travel to Norway in some years... hopefully with really good Maps :-) )

I wil lwork with this ;:) thx. And welcome to Norway anytime..