Grid overlay for maps
Hunter Geophysics
Global Mapper UserTrusted User
Hi Mike,
A few years ago, I did a survey of a cemetery and ended up producing a map with a 2x2 metre grid overlay on the maps so that the cemetery could figure out where things were on the ground without having to get out a surveyor (i.e. they could just count the grid lines from a known point to figure out the distance to something that I had found underground).
I think the option used to be in the Configure menu.
I need to do this again but can't seem to figure out how to do it. I note in the Configure menu there is the Grid Display section, with custom grid spacing options (measured in "ground units").
How can I project a 2x2m grid over my maps?
I know I could use the 'create regular grid of features' to create a regular grid, but that creates a huge amount of features (my site is 500m x 300m), and causes the computer to crash.
Thanks in advance for your help.
Dave
A few years ago, I did a survey of a cemetery and ended up producing a map with a 2x2 metre grid overlay on the maps so that the cemetery could figure out where things were on the ground without having to get out a surveyor (i.e. they could just count the grid lines from a known point to figure out the distance to something that I had found underground).
I think the option used to be in the Configure menu.
I need to do this again but can't seem to figure out how to do it. I note in the Configure menu there is the Grid Display section, with custom grid spacing options (measured in "ground units").
How can I project a 2x2m grid over my maps?
I know I could use the 'create regular grid of features' to create a regular grid, but that creates a huge amount of features (my site is 500m x 300m), and causes the computer to crash.
Thanks in advance for your help.
Dave
Comments
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Dave,
The General tab of the Configuration dialog has the gridding options right at the top. Just enable a 'Current Projection Grid' with Custom Grid Spacing of 2m. You would need to have your projection set to a projected system with units of meters, like UTM, on the Projection tab of the Configuration dialog.
Thanks,
Mike
Global Mapper Guru
geohelp@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation -
Hi Mike,
Thanks for your reply. That's exactly what I have been doing, but it keeps generating grid lines at 5km intervals instead of 2m.
I have it set to 'Current Projection Grid' and a 2 'ground unit' grid spacing. The project is UTM, zone -55, datum GDA94 and planar units is set to meters.
Snap 2014-05-28 at 09.17.01.pngSnap 2014-05-28 at 09.17.13.pngSnap 2014-05-28 at 09.19.25.pngSnap 2014-05-28 at 09.21.40.png
I understand Global Mapper doesn't like showing grid lines when zoomed out (due to the large number of grid lines that would be displayed), but as you can see from the attached screenshots, this happens even when zoomed right in.
I'm not sure what I'm doing wrong...
Thanks,
Dave -
Dave,
That all looks correct. I just tried it and got the 2m grid lines. There are 3 different levels of grid lines so you can have different styles for different levels of importance of grid lines. I suspect you may have turned off all but major grid lines.
If you go to the Vector Display tab of the Configuration dialog and open up the line filter dialog and make sure all 3 Grid Line types are enabled. You can also check the style used for them on the Line Styles tab of the Configuration dialog.
Thanks,
Mike
Global Mapper Guru
geohelp@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation -
Nope, still no luck.
The grid line styles are also black and 1px wide, so they should be visible...
Snap 2014-05-28 at 16.44.38.pngSnap 2014-05-28 at 16.45.23.pngSnap 2014-05-28 at 16.45.38.pngSnap 2014-05-28 at 16.45.43.png -
David,
Do you ever see a warning about having too many grid lines? Can you save a workspace after setting up the grid like that and send it to me so I can try on my machine to see if there is something odd in the Map Layout for the grid? I'm not seeing anything wrong in your attached images.
Thanks,
Mike
Global Mapper Guru
geohelp@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation -
I do get the warning message, but only when zoomed out.
The GIS data is of a commercial nature and so I cannot upload it to a public forum. Instead, may I email it to you via that geohelp@bluemarblegeo.com address please?
Thanks,
David -
Snap 2014-05-29 at 07.47.46.png
Actually, I just closed a large geological map layer, zoomed into the cemetery itself and re-applied the grid lines and it's now working.
Thanks for your help.
Unfortunately, I've now got a new problem, though. As shown in the attached screenshot, the grid lines are running N-S or E-W (understandable). However, my client needs the grid lines to be rotated so that they run parallel to the boundary fence (shown in the screenshot as a red line). Is it possible to rotate the grid lines so that they run parallel to the fence?
Thanks again,
David -
David,
Yes, you could do that by creating either a rotated regular grid of features, or use a rotated projection. Some projections, like Transverse Mercator, support providing a rotation angle to rotate the entire projected system. So you could center the projection on the cemetery, then rotate by whatever angle you need to make the cemetery boundary perpendicular to the projection grid.
Thanks,
Mike
Global Mapper Guru
geohelp@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation -
Ok, that sounds ideal. Could you please explain how to do that?
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If you just go to the Projection tab of the Configuration dialog and select a Transverse Mercator (or Orthographic would work well), then set the Central Meridian and Origin Latitude to a lat/lon near your data (i.e. at your desired origin point). There will also be a Rotation Angle parameter. Just set that to the angle to rotate by. You can play with a few values and hit Apply in between until you get something that visually looks good if you don't want to measure the angle.
Thanks,
Mike
Global Mapper Guru
geohelp@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation -
Brilliant; got it all working. Thank you very much for your help.
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