Differences

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--- en:help:v2:elevations [2018/01/25 16:32] – alpinequest
+++ en:help:v2:elevations [2018/12/07 17:44] – alpinequest
@@ Line 1: / Line 1: @@
-<sub>[[en:help|Online Help]] > [[en:help:v2|AlpineQuest 2.x]] > [[en:help:v2:maps|Maps & Layers]]</sub>
+<sub>[[en:help|Online Help]] > [[en:help:v2|AlpineQuest 2.x]] > [[en:help:v2:maps|Maps & Layers]] > Digital Elevation Model (DEM)</sub>
 ====== Digital Elevation Model (DEM) ======
@@ Line 5: / Line 5: @@
 The application is able to download and store elevation values of remote locations and let you use them in various ways, even while being offline.
-Those elevations come from various sources including the SRTMGL1(v3) database and are currently available between latitude 56°S and 60°N with a precision of 1 arc second.
+Those elevations come from various sources including the SRTMGL1(v3) database and are currently available between latitude 56°S and 60°N with a precision of 1″ (1 arc-second).
 \\
@@ Line 32: / Line 32: @@
 \\
-If you have troubles downloading elevation values areas, you can check that:
+If you have troubles downloading areas of elevation values, you can check that:
   * Your Internet connection is active;
   * The option ''"**Auto download elevation data**"'' is checked (you can also access it directly from the ''"**Maps**"'' menu, in the ''"**Options**"'' section);
@@ Line 43: / Line 43: @@
 When the use of elevation data is activated, a new set of maps and layers is added to the installed maps list. Those maps and layers are generated by the application based on the stored elevation data, they do not require any additional download.
-The list contains:
+The set contains:
-  * ''"**DEM Height**"'' {{:icon_01.png?nolink}}: a map associating each elevation value with a different color;
+  * ''"**DEM Heights**"'' {{:icon_01.png?nolink}}: a map associating each elevation value with a different color;
   * ''"**DEM Terrain**"'' {{:icon_02.png?nolink}}: a map with more close to reality elevation colors, hills-shading and grayed cliffs (>45°);
-  * ''"**DEM Hillshade Layer**"'' {{:icon_03.png?nolink}}: a layer emphasizing relief;
+  * ''"**DEM Hillshade Layer**"'' {{:icon_03.png?nolink}}: a layer that can be added over any map, emphasizing relief by simulating hill shades;
+  * ''"**DEM Slopes (+30°) Layer**"'' {{:icon_04.png?nolink}}: a layer that can be added over any map, emphasizing steep slopes: yellow (>30°), orange (>35°), red (>40°) and purple (45°);
+  * ''"**DEM Heights (sensitive)**"'' {{:icon_05.png?nolink}}: a map showing the smallest elevation variations;
 {{ :en:help:v2:maps:elevations-maps.jpg?nolink }}
@@ Line 55: / Line 57: @@
 \\
 When [[en:help:v2:landmarks:local-track-create|manually drawing a path]] or [[en:help:v2:landmarks:auto-routing|automatically drawing a path along roads]] over an area with elevation values stored, you can get the elevation profile and gain of that path:
-  * Click anywhere on the path {{:icon_01.png?nolink}} and select its name {{:icon_02.png?nolink}};
+  * Tap anywhere on the path {{:icon_01.png?nolink}} and select its name {{:icon_02.png?nolink}};
   * Select ''"**Details**"'' {{:icon_03.png?nolink}} and check the ''"**Statistics**"'' {{:icon_04.png?nolink}} part.
 {{ :en:help:v2:landmarks:auto-routing-4.jpg?nolink }}
+\\
+===== How to delete stored elevation data? =====
+\\
+In order to delete the elevation data stored on your device:
+  * Tap on the "''**Elevation data coverage**''" menu icon {{:icon_01.png?nolink}};
+  * Select "''**Clear data**''" {{:icon_03.png?nolink}};
+  * Tap "''**Ok**''" {{:icon_04.png?nolink}} to confirm;
+Independently, you can delete the data used by maps and layers generated from the stored elevation data. To do so, select the menu icon {{:icon_02.png?nolink}} of the map you want to delete the data.
+{{ :en:help:v2:maps:elevations-clear.jpg?nolink }}
 \\
@@ Line 66: / Line 81: @@
 If you don't want to use DEM values automatically downloaded by the application, you can use your own files. As long as the application finds the elevation data it needs, nothing will be downloaded.
-You must use DEM files in the ''"**.HGT format**"'' (either 1201 or 3601 values per lines), following the usual rules:
+You must use DEM files in the ''"**.HGT**"'' format (either 1201 or 3601 values per lines), following the usual rules:
   * File names must follow the .HGT naming convention;
   * Files containing 1201x1201 values (3″) must have a size of ''"**2,884,802 bytes**"'';
@@ Line 73: / Line 88: @@
 The files must be copied inside the sub-folder ''"**/cache/dem/**"'' of [[en:help:v2:settings:storage#how_to_locate_the_application_folder|the application folder]] (the same folder used by the application to store the downloaded elevation data).
-{{:icon_help.png?nolink}} If your own data doesn't cover a requested area, the application will automatically download the missing data in its own format which may interfere with your own data. You can completely turn off the automatic download of data using [[en:help:v2:settings:user-settings|the user setting]] ''"**maps.features.elevations.auto_download=false**"''.
+{{:icon_help.png?nolink}} If your own data doesn't cover a requested area, the application will automatically download the missing data in its own format which may interfere with your own data. Be sure to turn off the automatic download of elevation data (see first paragraph).
+\\
+===== Problems with elevation data =====
+\\
+**What if I get error messages when using elevation data?**\\
+It's likely because the elevation data storage is corrupted. Most of the time, this is due to "cleaning/optimizing" applications that delete parts of the storage (usually the biggest files) and claim to have freed space. If you use such application, be sure to correctly setup it. To fix the errors, you need to [[en:help:v2:elevations#how_to_delete_stored_elevation_data|clean up the stored elevation data]].