Adding Longitude and Latitude Lines to a map

Adding Longitude and Latitude Lines to a map

by tonytran2015 (Melbourne, Australia).

Click here for a full, up to date ORIGINAL ARTICLE and to help fighting the stealing of readers’ traffic.

(Blog No.78).

#find North, #GPS, #navigation, #off grid, #adding, #longitude, #latitude, #coordinate, #lines, #map,

Adding Longitude and Latitude Lines to a map.

Locating where you are using the internet is great but there are times when you have no mean to connect to the internet and you have to use GPS for positioning without any assistance via the internet. Such a situation may arise when you have no internet coverage or when going hiking.

If you want to use your GPS off-grid with any map, you need to draw on top of the map an accurate system of regularly spaced longitude and latitude coordinate lines.

This posting shows how to add the lines.

1. Making a map graduated with Longitude and Latitude Lines.

1. Choose a map with your required resolution and range. The resolution differs for different application: For city street maps resolution should be better than 2m, for country town maps, resolurion only need to be better than 5m as houses are widely separated, for touring, exploring maps, resolution can be upto the (1/10) of the visual range, etc…

2. Make sure that the top of the map points to true North. (In some countries, maps are deliberately oriented at angle to true North, probably for security reasons.)

Figure: Openstreetmap for Melbourne with 3 airport landmarks. Map is used under Open License from Open Street Map, the data are owned by Open Street Map Contributors.

3. On that map, find some unmistakable features such as a well known Airport or Helipad, a Light House, a TV Transmission Tower, a Town Hall, Churches, Schools, Cottages in a forrest, sharply defined mountain peaks, trail intersections… with known longitudes and latitudes. Their coordinates are usually given on the Internet or or easily extracted from Google Map or Navigating Apps.
Find two to four such fearures located near the four extreme corners of your map. They will be used as land marks.

Ecample:

The 3 landmarks that can be used here are:

a. Melbourne Tullamarine airport, Elevation AMSL 434 ft / 132 m, Coordinates 37°40′24″S 144°50′36″E

b. Melbourne Moorabin airport, Elevation AMSL 50 ft / 15 m, Coordinates 37°58′33″S 145°06′08″E

c. Melbourne Essendon airport, Elevation AMSL 282 ft / 86 m, Coordinates 37°43′41″S 144°54′07″E

4. On a separate fresh sheet of paper make a coordinate grid of longitude and latitude covering your range.
On this sheet with grid but no map, mark the coordinates of your land marks.

Figure: Melbourne Tullamarine and Moorabin airports on a grid map.

5. Check that the shape of the figures formed by the land marks are similar in both the grid sheet and the map. You may have to stretch or shrink the grid vertically and then horizontally to have a fit. The figures should be similar if no mistakes have been made. If the shapes are similar you can proceed to the next step.

6a, If the map and grid are both digital, they can be superimposed in the computer to produce the following map with added coordinate lines:

Figure: Openstreetmap for Melbourne with added cooodinates. Map has been modified from original map used under Open License from Open Street Map, the data are owned by Open Street Map Contributors.

The added lines are on round figure coordinates and are 2 minutes of arc apart. The intersection nearest to the NW of Tullamarine airport has coordinate (144°50′E, 37°40′S ).

6b. If you are using printed map: Join two distant landmarks on the coordinate sheet and notice where the lines of “minute of longititude” and of “minute of latitude” intersect it

7. If you are using printed map: Reproduce that line, with all its intersecting points, on the actual paper map.

8. If you are using printed map: From these intersecting points project corresponding vertical lines to make the “minute of longititude” lines and horizontal lines to make “minute of latitude” lines.

9. The map is now graduated with longitude and laritude lines.

10. Its grid can now be used as a base to draw finer grids for detail maps with higher resolutions.

2. Using GPS with maps.

You can download a (preferably topological) map of your area to practice drawing the coordinate lines, the constant altitude lines and learn about the accuracy of the values of longitude, latitude and altitude given by your GPS apps.

It is preferable to use topographic maps with old fashioned land marks (such as churches, tall towers …). Topographic maps give the additional constant ground altitude contours (relative to some mean sea level surface). Constant altitude curves are the faint brown curves on the map illustrated here. The height of each contour is given by a small number. The altitude values of 20m and 10m have been highlighted in this example map by two red circles.

Figure: Opentopomap for the area in my test. Map is used under Open License from Open Street Map, the data are owned by Open Street Map Contributors.

References

[1]. tonytran2015, Using GPS in off-grid situations., posted December 6, 2016

[2]. tonytran2015, Measuring angles and distances for outdoor survival, survivaltricks.wordpress.com,

https://survivaltricks.wordpress.com/2016/06/29/measuring-angles-and-distances-for-outdoor-survival/, posted 29/6/2016.

[3]. tonytran2015, Selecting and using magnetic compasses, survivaltricks.wordpress.com,

https://survivaltricks.wordpress.com/2016/07/09/selecting-and-using-magnetic-compasses/, posted 09/7/2016.

[4]. , BBC News, UK radio disturbance caused by satellite network bug, http://www.bbc.com/news/technology-35463347, 2 February 2016.

Added after 2018 Nov 26:

The Thors’ son urged people travelling to remote locations without mobile coverage to download a GPS application to their phones ahead of their journey, as well as an offline map for their destination.

[5]. https://mobile.abc.net.au/news/2018-11-26/german-tourists-died-central-australia-walked-17km-heat-stress/10554408

PREVIOUS SURVIVAL blogs

, posted on

Circumpolar Stars Nth

Finding North with a lensatic compass, posted on August 21, 2017

Compass-Magnetic

Slide Sky-Disks with grid masks showing azimuths and altitudes.

Slide Sky-Map for displaying tropical stars.

Click here for my other blogs on divider43.jpgSURVIVAL

Click here go to Divider63D400 Home Page (Navigation-Survival-How To-Money).

SUBSCRIPTION: [RSS – Posts], [RSS – Comments]

MENU: [Contents][Blog Image of Contents ][Archives ] [About]

22 thoughts on “Adding Longitude and Latitude Lines to a map

  1. I know this if off topic but I’m looking into starting my own weblog and was curious what all is required to get set up? I’m assuming having a blog like yours would cost a pretty penny? I’m not very internet savvy so I’m not 100 certain. Any recommendations or advice would be greatly appreciated. Thank you|

    Like

  2. I think this is one of the most important information for me. And i’m glad reading your article. But want to remark on few general things, The web site style is ideal, the articles is really nice : D. Good job, cheers|

    Like

  3. hello there and thank you for your information – I have certainly picked up something new from right here. I did however expertise some technical issues using this site, as I experienced to reload the web site lots of times previous to I could get it to load correctly. I had been wondering if your web hosting is OK? Not that I’m complaining, but sluggish loading instances times will very frequently affect your placement in google and can damage your quality score if advertising and marketing with Adwords. Anyway I’m adding this RSS to my email and can look out for a lot more of your respective exciting content. Ensure that you update this again very soon.|

    Like

  4. Hi just wanted to give you a brief heads up and let you know a few of the images aren’t loading properly. I’m not sure why but I think its a linking issue. I’ve tried it in two different internet browsers and both show the same results.|

    Like

  5. Reblogged this on and commented:
    Grids give coordinates for many different things, such as pinpoint artillery. The rule of thumb, is to “Read Right Up”. Start from the left, work to the right, then go up.

    Liked by 1 person

Leave a Reply to Catheryn Howryla Cancel reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.