People planning to walk on a GR or GRP in France are well catered for, with Topoguides (if one exists for their planned walk) and TOP 100 maps, which have GRs marked on them.
The larger scale TOP 25 maps are excellent, and all things being equal, are definitely the maps to use, but would require the walker to carry a huge number of maps for a long walk. To avoid this, you can take screenshots of your proposed GR or GRP walking track from the online TOP 25 map in Géoportail and then print them out.
However, if you plan to make up your own route, you can design it using Google Maps, make a KML file of that route, and then import it into the online TOP 25 map in Géoportail.
This TOP 25 map can then be used to make hard copy maps, or, for people who prefer using a mobile phone (not us), they can access their map while walking via a paid subscription to the IGN Outdoors App.
This process is very time-consuming and certainly not for everybody (you really need to enjoy playing with maps), but the method described here works very well for us, and we would never go back to using commercial maps.
The method described is more detailed than necessary because our aim is to produce a continuous line on the final IGN TOP25 map that we can insert into our website, which we have been doing since 2015. For general users, small gaps in their route are of no consequence and they can take a lot of time to accurately fix.
To begin, a KML file is created using Google Maps, you must have a Google account to follow this explanation.
The example given below designs a four-day walking route from Randan to Châtel-de-Neuvre, with overnight stops in Gannat, Bellenaves and St-Pourçain-sur-Sioule. This was actually part of our 2018 walk.
The first map we make will cover the first two days, from Randan to Bellenaves.
We start by clicking this Google Maps link. It will take you to your Google Maps which is on your Google Drive. You will see a list of any maps you might already have.
Click “CREATE A NEW MAP”, then click the “Add directions” icon, indicated by the red arrow on the right. Another Untitled Layer appears with two boxes, A and B.
The first stage of our walk is from the Hôtel du Centre, Randan, to the camping ground in Bellenaves. Enter Randan and Gannat.
A suggested driving route will appear, which is usually totally useless for walkers. Next click the word “Driving”, then the Walking icon, which gives an only slightly better route.
Drag the endpoints of the suggested route to exactly where you intend to stay (see left).
As we are comfort-loving walkers, we always use Google Street View to check on any bars/cafés (coffee shops) and boulangeries (bakeries) along the way for possible refreshment stops. Any that we find we mark on the Google map with an icon.
For this walk, there didn’t seem to be any, except at the start in Randan, which we marked with purple icons using the top Untitled Layer. Give suitable titles to the map and the two Untitled Layers.
Another use for Google Street View is to take a virtual drive on a particular road to see the state of a possible walking track as it crosses the road.
If there is a GR going our way, we may use it but we never follow them slavishly, as they are usually too circuitous for our liking.
You can check for GRs in the area by visiting the Géoportail website. On the home screen search (Rechercher un lieu, une adresse, une donnée) for Randan. The default view is aerial photographs (Photographies aériennes).
To display the TOP 25 map, click CARTES (Maps), indicated on the right by the top red arrow, then Voir tous les fonds de carte (See all the map types). Choose Cartes IGN classiques. Click CARTES again to hide this menu. To see the TOP 25 map, zoom in until a Scale (Échelle) of 1:17,055 is shown at the bottom left-hand corner.
A useful feature of Géoportail is that if you click vos cartes personnalisées (your maps) on the Home page, you will be taken to the last map you looked at.
So with all this in mind, drag the blue line on your Google Map and try to find a suitable walking route. What we decided on is shown on the Google Map to the left.
When we actually did this walk, we had a problem at the place marked by the orange icon. If you look at this spot on the TOP 25 map, or the satellite view in your Google Map, you will see it is in a bois (forest), and working forests do have their own unique problem – changed tracks due to forestry operations.
To add to our problems, the changed track was right on the edge of our home-made map. This meant that we had to go off our map into the unknown.
As always in these circumstances, we were saved by the MAPS.ME app (a set of offline maps) which we had downloaded onto our iPod before starting our walk.
For the time being, we are finished with day 1 of our walk. As Google is constantly saving your maps as you edit them, your map is already saved in My Maps on your Google Drive.
It is now time to find a route for the second day of our walk. We do this on our current map by clicking “Add directions” icon, and then using the same process, creating a walking route from Gannat to Bellenaves camping ground.
After checking on Google, we decided to go through Ébreuil because we could have a second breakfast there. You will notice on the TOP 25 map that the GR463 goes from Gannat to Ébreuil, so we could have used it, but decided to make our own way.
So our plan was to have breakfast on the way out of Gannat, find a way to Ébreuil, and then roughly follow the GR463 to Bellenaves.
What we decided on is shown on the Google Map to the right.
However, there is a problem that sometimes occurs on Google Maps – not all tracks that are on a TOP 25 map are shown on a Google Map!
Notice that the stretch of the GR463 just after Ébreuil (orange icon above), between the two red arrows on the TOP 25 map (left), is not shown between the two red icons on the greatly zoomed in Google map (below).
How to overcome this problem and bridge the gap? It is a two-step process.
The first step is to replace the suggested route with two routes; the first from Gannat to where the problem starts (B), the second starting from where the problem ends (A) to finish at Bellenaves.
The way to overcome the problem of no actual physical address on either side of the gap is to start and finish the first line at Gannat, then drag point B out to the gap, and then do the same for the second line, starting and finishing at Bellenaves, and then dragging Point A back to the gap.
Now delete the original suggested route. Your map at the gap should now look like the map on the right.
As the second step of the solution involves joining these two routes to make a continuous route from Gannat to Bellenaves, it is very important to get the sequence and direction of the two replacement routes correct. Otherwise, the final route will be incorrect and very messy!
To help find our way around the KML file when we come to edit it, it would be a good idea to rename the layer containing the line starting in Gannat to “Gannat to Bellenaves”. The control panel on your map should now look like the one on the left.
There is an important constraint with Google Maps. The maximum number of layers in each map is ten. Our map currently has four layers, so we have room for more. We could put the next day’s route on this map, but in order to show how to join two maps, we will now start using a new map.
To open a new map, either click the link you previously used above, or just click the three vertical dots menu on your current map (indicated by the red arrow on the image above), then click New map.
Day 3 of our walk goes from the camping ground in Bellenaves to the camping ground in St-Pourçain-sur-Sioule. Enter these names in the boxes, and go via Chantelle for a refreshment stop. The walking route we chose is shown right, and the control panel for the map is shown below.
Now we can find a route for our fourth and final day, St-Pourçain-sur-Sioule to Châtel-de-Neuvre, with a coffee stop in Contigny.
Comparing the suggested route above to what is shown on the TOP 25 map, you will notice that the GR300 goes along the bank of the Allier river on the edge of a réserve naturelle (nature reserve) from le Petit Bressolles to Châtel-de-Neuvre. The map below is a magnified view of the problem section.
Sounds like a good walk, but the GR300 track is not shown on the Google Map, hence the detour on the D2009, a very large road!
Once again we have to bridge the gap. However this time it is a lot easier because the gap is very close to one end of the suggested route.
Just drag the endpoint B that is now at Châtel-de-Neuvre to the start of the gap, and then create another line that goes from the end of the gap to Châtel-de-Neuvre (see below).
As before, to help find our way around the KML file when we edit it, it would be a good idea to rename the layer containing the line going to the gap as “St-Pourçain-sur-Sioule to Châtel-de-Neuvre”.
The control panel on this map should now look like the one on the left.
It is now time to create the KML files for the two maps you have created, and then do two simple edits to both files. We will start with our first map, Randan to Bellenaves.
Open the first map. The Icon layer is not required in the exported KML file. However, the information it contains may be useful to enter on your printed maps later on, so rather than deleting it, we will keep it on this map, but delete it from the KML file later.
On your map’s control panel, click the three-dot menu, then Export to KML/KMZ file (see right).
Select Export the KML file, then click Download. There now should be a KML file in your Download directory called Randan to Bellenaves, which we will now edit.
To edit a KML file you will need a text editor. If you don’t have one on your computer, you need to download one. There are many to choose from, I like both Notepad++ and Sublime Text.
Open the KML file with your text editor. Incidentally, you can look at and edit the KML file of any map on this website. To do this, click “View larger map” (icon in top right-hand corner of the map), then click the three-dot menu, then Download KML.
The KML coding is not difficult to follow. For example, to the left, you can see the document starts on line 3, and the name of the map (between <Name> and </Name>) is what we gave it, Randan to Bellenaves (line 4).
Also, <Folder> and </Folder> mark the start and end of a layer.
From line 6 to line 117 are line and icon formatting, which we can ignore. This is followed by the Icon layer which starts at line 118 (right).
The Icon folder ends at line 183 (see below), and then the Randan to Gannat layer starts. The huge string of numbers following are the latitudes and longitudes of each point on the Randan to Gannat route.
Eventually, this folder (layer) will be the only folder in our KML file.
We could edit some names in the editor, but it is easier and less confusing to do that in Google Maps later.
The first edit will merge the two folders into one. Scrolling down to the end of the first string of coordinates (below), we are going to delete the shaded lines of code.
This code is made up of markers for either end of the route (from lines 1097 to 1114), followed by three lines that are folder dividers (lines 1115 and 1116), and the name of the folder that is about to be deleted (line 1117). The deletion of these three lines causes the first folder to be extended to the next </Folder>, which is at the start of the gap.
The last piece of editing is to close the gap and extend the folder again. Scroll down to the end of the folder. From the end of this folder to the start of the next folder is the gap. (see below).
If you delete everything from line 1822 to 1851 then the last coordinates of the previous folder (3.08073, 46.12001,0) will now be adjacent to the first coordinates of what was the next folder (3.07557,46.12497,0). This means that when this file is loaded back into Google Maps a straight line will be drawn between these two points.
However, before you do this delete, you should be aware of another Google Maps limitation you might encounter. If you have a tidy mind, you might want to edit this straight line to the approximate route of the track as shown in the TOP 25 map.
This is quite possible because when you upload a KML file to Google Maps, the restriction that the route is confined to tracks/roads that are drawn on Google Maps is lifted – each point on the route can be moved to any point on the map.
But the limitation is that beyond a certain maximum number of points on a line, you can’t edit the points on that line. So what is the maximum number? About the number of points on a longish day’s walk, and this line, Gannat to Bellenaves, is just over the limit!
So firstly, for the non-tidy minds, do the delete, then save the KML file. Finally, create a new map as before, then import the KML file.
And now for the tidy minds. Rather than doing the delete, save the KML file, then create a new map as before, then import the KML file. Because the second day’s route is broken in two, the two parts are short enough to be edited.
Click a line on one side of the gap, drag the endpoint to the endpoint on the other side of the gap, and then shape the route by dragging the handle that is midway between two points. To help get a good match with the actual road, switch to Satellite View.
When you are satisfied, export the file, then edit by deleting all the coding in the shaded area above. Finally, create a new map as before, then import the KML file.
Now both tidy and non-tidy-minded people should have a control panel on their map that looks like the one on the right.
We can simplify the control panel by deleting the Icon Layer and any odd icons remaining, and also renaming the two lines as “Randan to Gannat” and “Gannat to Bellenaves” (see left).
Now go through the same process to create a KML file for the Bellenaves to Châtel-de-Neuvre route. This time the route with the gap, St-Pourçain-sur-Sioule to Châtel-de-Neuvre, is below the limit of points for editing, so tidy minds can do the same as the non-tidy minds when editing the gap.
When finished, your control panel should look like the above panel.
To finish, we want the coding for the four routes to be in the same folder, and in the correct order (as shown on the left). Copy the two lines from the second map’s KML file and paste them into the first map’s KML file, directly after the coding of its two lines.
In other words, copy everything between the <Folder> and </Folder> markers in the second file, and paste it directly before the </Folder> marker in the first file.
After simplifying, the control panel should look like that on the left with four lines in one layer, and the resulting map is shown below.
Export the KML file to your Downloads, as before. All that remains now is to import the KML file into Géoportail.
Go to the Géoportail website, and click the star in the top right-hand corner to create an account.
When you have an account, click Mes données (My data). Firstly, give the file you are about to import a name (Nom de la donnée). Now click Ajouter un import (Add an import). Click Choose file, then navigate to your Downloads, click your KML file, then Importer on Géoportail.
Your walking route should appear (in blue) on the Géoportail map. Mine is shown below (it can be slow to load).
Zooming into a scale of 500 m produces the TOP 100 map, and one more zoom (also with a scale of 500 m) shows the TOP 25 map. This is the best scale to use when walking.
If the map below is blank, click here
Using this scale, we take a screenshot of this map, crop it using Photoshop, and print it. We repeat this procedure, working our way along our route.
We usually set off with around 100 double-sided A4 pages of these maps, and discard them as we go along. This sounds a lot, but it is only the weight of six TOP 25 maps, whereas we would need at least 25 of them to cover the same distance.
With the opacity of the line at 100%, we have found that the detail of what type of track/road is on our route is lost, so we reduce the opacity to about 35%.
There a setting for this in the KML file, but Géoportail seems to override this. However, the opacity of a line can be set in Géoportail.
In the image above, click the pile of pages icon (indicated by the red arrow).
Then click at the bottom of the pane of your map, labelled 2018 Short Walk (indicated by the red arrow below). There is a bit of skill involved in finding the correct spot.
When you do click the correct spot, the opacity control appears (see below right).
A few more hazards you might encounter with Google Maps. Some very small tracks are shown on Google Maps, but only when you zoom right in.
If you look closely at the gap on your first map you will see that part of the gap actually had road marked, but only appeared at high zoom.
Also, Google won’t suggest a walking route through a large roundabout, presumably because of the danger factor. This can mean the suggested route may involve a very large, and unnecessary, detour when all that is required is some caution when negotiating the roundabout. When making our maps, we treat this as just another gap.
In conclusion, there seems to be no limit to the number of lines that can be loaded into a Google Map’s layer. For example, this is the Google Map of our 33 days of walking in 2018, and the Géoportail TOP 25 Map of the same walk.
I have developed this method of map-making over a period of a few years, and I would appreciate any feedback, particularly about the use of Géoportail, which works very differently from Google Maps, and I am sure that I still have a lot to learn.
Thanks
For further information you can contact me, Keith, at: