Changes between Version 2 and Version 3 of WikiStart

Timestamp:

Jul 26, 2018 12:51:54 PM (7 years ago)

Author:

Uriel

Comment:

--

WikiStart

@@ -10 +10 @@
 
 === SRTM Data 
-Maperitive uses NASA SRTM data to generate shaded terrain maps. In the past, Maperitive was able to connect to NASA's servers and download the data as needed. Since then, NASA has locked down the servers behind a free password. A newer version of Maperitive exists which might have a workaround for this issue, but this documentation presumes Maperitive can't download the data. Instead of Maperitive downloading the data, it can be downloaded manually and then just placed in a location that Maperitive expects SRTM data to be; then it will not attempt to download it again.
+Maperitive uses NASA SRTM data to generate shaded terrain maps. In the past, Maperitive was able to connect to NASA's servers and download the data as needed. Since then, NASA has locked down the servers behind a free login. A newer version of Maperitive exists which might have a workaround for this issue, but this documentation presumes Maperitive can't download the data. Instead of Maperitive downloading the data, it can be downloaded manually and then just placed in a location that Maperitive expects SRTM data to be; then it will not attempt to download it again.
 
 The SRTM data comes in two resolutions:
-* [https://lpdaac.usgs.gov/dataset_discovery/measures/measures_products_table/srtmgl1_v003 SRTMGL1], 1-arcsecond data, divides the earth into images covering 1x1 degree lat/long of most of the land. Each file is 3601x3601 16-bit pixels (~26MB).
+* [https://lpdaac.usgs.gov/dataset_discovery/measures/measures_products_table/srtmgl1_v003 SRTMGL1], 1-arcsecond data, divides the earth into .hgt data files covering 1x1 degree lat/lon. Each file is 3601x3601 16-bit pixels (~26MB).
 * [https://lpdaac.usgs.gov/dataset_discovery/measures/measures_products_table/srtmgl3_v003 SRTMGL3], 3-arcsecond data. Each file is 1201x1201 pixels (~2.8MB).
 
-If downloading more than one file at a time, SRTM data is most easily obtained from NASA's servers using the [https://lpdaac.usgs.gov/data_access/daac2disk Daac2Disk] utility. This example command will download the entire SRTMGL1 dataset to the SRTMGL1 folder: {{{Daac2Disk_win.exe --shortname SRTMGL1 --versionid 003 --nometadata --outputdir SRTMGL1}}}. 
+If downloading more than one file at a time, SRTM data is most easily obtained from NASA's servers using the [https://lpdaac.usgs.gov/data_access/daac2disk Daac2Disk] utility. This example command will download the entire SRTMGL1 dataset to the SRTMGL1 folder: {{{Daac2Disk_win.exe --shortname SRTMGL1 --versionid 003 --nometadata --outputdir SRTMGL1}}}. This utility can also be used to download data within a set of lat/lon bounds using the {{{--bbox}}} parameter.
 
 To download the data from the web or using Daac2Disk, you will need NASA Earthdata account: [https://urs.earthdata.nasa.gov/home]. Once you have created your account, log in and from "My Applications", add the LPDAAC Data Pool.
+
+==== Using SRTM in Maperitive
+Once the entire world data is downloaded, a few things need to be set to use it properly in Maperitive. Copies of the STRMGL1 and GL3 datasets are on the USB drive in the folders STRMGL1 and SRTMGL3
+
+'''Filling in the gaps:''' Areas of the world which are entirely ocean have no corresponding SRTM file, but Maperitive will try to download the file anyway. The fix for this was to generate all-zero height files for any lat/long missing from the downloaded data set. The Python script fill_terrain_tiles.py automates this process. The filled-in datasets are on the USB drive in the folders SRTMGL1_full and SRTMGL3_full
+
+'''Linking the SRTM to Maperitive:''' In order for Maperitive to find the SRTM data, it must be placed in the correct folder: {{{X:\Maperitive\Cache\Rasters\SRTM1}}} or {{{X:\Maperitive\Cache\Rasters\SRTM3}}}. On the USB drive, this is performed by creating a softlink to the SRTMGLx_full folder, rather than making another copy of the file. You can use the windows utility [https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/mklink mklink] to do this; it can be run from the command prompt.
+
+To use the data in Maperitive, you must enter the command {{{set-dem-source name=SRTM1}}} or {{{set-dem-source name=SRTM3}}}.
+
+'''Generating the Shading:''' The nicest shading method Maperitive provides is called "Igor Shading", named after the creator of Maperitive. This will generate a single-color terrain shading of the world