|i want to make a simple 2D reference grid with 250 meter sides to place on a geographical location in google earth||johnfraser1||3/20/11 4:00 PM|
i live on the island of Saipan, where we are doing a survey for turtle nests which are on or near the beach. the project requires us to have a map of the survey area overlaid with a grid with sides of 250 meters. we would then take the measured gps coordinates of turtle nests and place the nest location on the map. it would be desirable for the grid to be aligned to latitude/longitude lines.
i have also physically located a couple of ngs survey markers in the area and measured their gps coordinates. to help gauge the accuracy of our own gps measurements i think it would be desirable to have one of the survey markers pegged to a corner of one of the grid squares.
so: how do i go about 1. making a 250m square grid pattern, 2. placing ithe grid on a google map area, 3. aligning the grid to lat/long lines and 4. pegging a corner of one of the grid squares to an ngs survey marker?
|Re: i want to make a simple 2D reference grid with 250 meter sides to place on a geographical location in google earth||Bestistmate||3/20/11 6:28 PM|
Hi John this is not really my line but i will try to help best ican .
!/ go to file. geo location>. add location . the google earth window comes up and you select your place you want like move the pins if required and then grab it .
that brings it into sketchup . you can then put your grids on . but before that you need to scale your map . and this is done by knowing a distance on the map ie a point point distance length of a building . when you know a size get the tape measure tool and measure start and end points to measure . then in the measurment box at the bottom you just put in the correct size nd press enter . It will ask if you want to rescale and u click yes . done. i would set the units to meters in the model info box ( window.> model info) draw you grid .(right click and erase the faces if u do not want them ) keeping the edges.
You can then select the all the grid and move around with the move tool. If you go to file > preview in google earth it then comes in there ane you can switch between . in earth you you can see the long and lat lines on in the view window .
Hope that help s, as i say not my line
|Re: i want to make a simple 2D reference grid with 250 meter sides to place on a geographical location in google earth||Gully Foyle||3/20/11 7:29 PM|
Use the From Scratch tool. See References.
|Re: i want to make a simple 2D reference grid with 250 meter sides to place on a geographical location in google earth||George Knowles||3/20/11 8:43 PM|
It’s not clear to me whether you want to do all this just in SketchUp.
FWIW, nearly forty years ago I lived and worked on Little Cumberland Island, Georgia, USA
Tell us more so we can help.
|johnfraser1||3/20/11 9:12 PM|
Hi Phil, Gully, George,
Thanks. in the end i want a view of the beach and nearby area with the 250m square grid overlay, turtle nest(s) pinpoints, a few local benchmarks(waypoints of permanent objects on my gps) and the lat/long lines for reference. i was thinking of making the grid in SketchUp and then viewing the whole scene in Google Earth. But anything the works towards those ends is fine and i'm open to suggestions.
yes i've been to a Cumberland Island, maybe not the small one but the island where there's a developed public camping ground plus houses on private property. the Green Turtle population in the western pacific has gotten very small, probably mostly due to legal consumption or poaching. the population here in the northern marianas is nearing the extinction level. even though it's illegal here, poaching is an ongoing problem. the program that's being set up will monitor any nests for hatching activity as well as for poachers.
so far i've only tried Phil's suggestion - i made a grid in SketchUp but when i viewed it in Google Earth, part of the grid disappeared under the terrain rising up from the beach. i pulled up some of the individual 250m squares above the surface to where i could see them again. after that, though, it was virtually impossible for me to get all of the (16) squares in the grid into a plane at the same height again. that's as far as i've gotten so far.
|Gaieus||3/20/11 11:46 PM|
If you are not planning to add 3D models to your map data, I think this is better to do in Google Maps or Google Earth. There you can add polygons (for a grid), placemarks (for your gps data) etc.
I am not an expert in this kml documentation (there are members here who are better though) but if you wish, I could also move your topic to either the Maps or the GE forums.
If you still want to stick to SU, there is probably some way to do this.
|johnfraser1||3/21/11 12:23 AM|
Thanks. this is proving to be a steep learning curve. if i can do it easier with Google Earth, that would be good.
following your suggestion, i tried to make a square in GE with the polygon tool but i can only seem to make amorphous shapes. is there a method to develop a grid with the polygon tool?
as far as moving my question, go ahead and move it to GE forums if you think a grid is doable in GE.
|Gaieus||3/21/11 1:14 AM|
Once you made a polygon in GE, right click on it in the side bar and save as... kml. You can open a kml file with a simple text editor and can enter all sorts of highly accurate data instead of the "amorphous" co-ordinates. I know this sounds a bit tedious way but after all, your gps data will need to be entered somehow.
Maybe instead of polygons, you could use individual lines crossing each other in a grid system, too.
If you were to do this in SU, I would also suggest to edit the imported imagery by adding the lines into the raster image otherwise you should be using somewhat thick geometry to properly represent those grids but then it would cause all kinds of Z-fighting in GE. Any kind of geometry should be "wrapped" onto the terrain, too. I think it would be more tedious that way.
|wo3dan||3/21/11 1:17 AM|
Hi John, Hi Gaieus,
Gaieus, why drag this away from our attention to some other forum? It's quite doable in SU to keep there or to "send" the results to GE.
Gully suggested creating the grid with the 'From Scratch' tool. Perfect tool. If that grid lacks height to pinch through the earths surface, give the grid some height, paint the vertical faces some translucent material and preview in/send to GE.
John, to me a grid of 250m sounds quite large to pinpoint nest locations to monitor. There aren't that many large remote beaches on Saipan, are there?
|johnfraser1||3/21/11 2:24 AM|
Hi Gaieus, Thanks. i'll try to work with the kml file.
Hi Wo3dan, yes 250 meters is a bit large for our area. it's a typical grid which has used by other people monitoring turtles. we will eventually use a smaller grid of 50 or 100 meters. Thanks.
FYI: here are the coordinates of a point on Wing Beach, Saipan, the area i'm making the grid for: 15°16'13.52"N 145°47'24.25"E
|Gaieus||3/21/11 2:36 AM|
Sure it can be done - I did not say it could not - just IMO the native GE tools (IF someone knows how to use them) are better.
In fact, there is a plugin - terrain reshaper - which allows you to create a grid that will already follow the bumps of the terrain so the grid would not "merge" and "hover" below and above the GE terrain:
These are still faint edges however and cannot be seen as well as some colour lines in GE.
Then there is this coords-text from datum plugin that allows you to add any spots by their co-ordinates into SU - these can then be labelled with 3D Text for instance to make it into GE (text entity will not export):
The above version is buggy though, there is a revised version at SCF (Geo and I helped to identify the issue in late January):
So I have no intention to chase John away...
|Bestistmate||3/21/11 5:16 AM|
|George Knowles||3/21/11 9:16 AM|
Here’s a SketchUp terrain model of Wing Beach akin to what may work for you.
Download SketchUp Model — Wing Beach, Saipan with 25 Meter Grid Oriented N-S
Let us know if something like this works for you and then we’ll help you sort out the details of how to create it.
|George Knowles||3/21/11 11:00 AM|
Here’s an example of the SketchUp grid in Google Earth v220.127.116.112 (beta).
Download Google Earth KMZ File — Wing Beach, Saipan 25 M Grid
|wo3dan||3/21/11 2:38 PM|
Since I grew up on an island the size of Saipan (in the Caribbean) and having spend quite some time swimming, snorkling, sailing.... well, you know, I just had to look at Saipan. The beach that I came up with as being a likely spot for turtles, was..... Wing Beach. (Was it luck?) Remote beach, quiet sea, contrary to on the other side of the island.
In (we say on) Aruba there also were turtles on some beaches each year. I hope your project will be prosperous and many turtles will benefit from it.
If you need any help using SU/GE for the project, let us know.
|johnfraser1||3/22/11 3:39 PM|
Thanks. i viewed your grid in GE. that's exactly what i was trying to make. (btw, i was not able to download your SU model.)
i then made a 25m grid like yours From Scratch in SB. when i viewed it in GE earth it was opaque white and obscured the ground. i tired to delete the opaque area within each grid square but could not.
when i viewed my grid in GE, it still disappeared into the rising terrain like before. in SU i tried to pull it up but the push/pull tool would not work.
did you make your grid above the terrain or drape it on the terrain?
regarding the From Scratch(FS) in SB - i went back to FS to make another grid with bigger, 50m, squares but it didn't happen. in SB/FS the tick marks would not appear after i clicked on the origin one or more times. i reread and followed carefully the FS instructions, i tried several times to reproduce the grid i had already made but just couldn't. any suggestions as to why i was unable to get FS to work again?
to sum it up i need to: 1. make the grid transparent, 2. keep the grid from disappearing under the terrain and 3. get SB/FS to work again. thanks again.
|George Knowles||3/22/11 3:50 PM|
Try downloading the model again.
You’ll need to see the model to understand how the grid was made for Google Earth.
|johnfraser1||3/22/11 4:25 PM|
ok got it. initially there was a message from google saying, "Sorry, the page (or document) you have requested is not available". however when i clicked on a "documents" header on the same page, your SU model was there on a list.
in GE can see your SU grid on the wing beach location. But i still don't know how you created the grid in SU and placed it on the terrain so the whole grid is visible. could you back up and guide me thru it again? sorry, this is probably getting tedious.
nice call on wing beach as a turtle site. it's one of only two or three beaches that turtles still come to here. there were others but the turtles moved away from the populated areas.
|johnfraser1||3/22/11 4:31 PM|
Thanks. i clicked on "file" (and other headings) but could not find the " file> geolocation" option in GE or SU in order to "turn off the terrain".
|George Knowles||3/22/11 5:26 PM|
No worries, John
|Gully Foyle||3/22/11 5:42 PM|
> ...it was opaque white and obscured the ground. i tired to delete the opaque area within each grid square but could not.
To eliminate the background from the grid made by From Scratch, here's an easy way:
• Edit (double-click) the grid group.
• Select Wireframe from the Styles toobar.
• Press Ctrl-A, to select all (visible), then reselect colored with textures.
• Hit escape to exit the grid group
• Paste the grid where you want it. It's the lines only.
• As a nice touch, paint the gridlines white.
See Reference 1.
|Gully Foyle||3/22/11 8:12 PM|
Sorry, I omitted a step:
• Press Ctrl-A, to select all (visible), then Ctrl-C to copy, then reselect colored with textures.
|George Knowles||3/22/11 8:15 PM|
The grid in the Google Earth KMZ file I posted earlier follows the contours of the terrain.
To begin …
Import the terrain from Google Earth
Click … Window > Layers to open the Layers manager.
Turn the Terrain Layer visibility ON
Now to align the Red - Green - Blue Drawing Axes with North …
Click … View > Hidden Geometry
Select the Axes tool.
Now note the Drawing Axes, Orange North Axis and Terrain Mesh are all aligned.
Click … View > deselect Hidden Geometry
Now to draw the perimeter of the grid …
Now to create the grid …
Note the terrain is a Locked Group that when selected displays a red bounding box.
Now to align the grid with the NGS survey markers …
When you have the grid positioned, click … Camera > Perspective
Now to Drape the grid on the terrain …
Confirm the grid is draped where you want it.
We don’t need to see the flat grid any longer.
Now to ‘extract’ the grid from the terrain …
Turn the Terrain Layer visibility OFF
Now to preview the contoured grid in Google Earth …
Paint the grid a contrasting color as Gully suggested.
Tidy up the stray edges of the grid with the Eraser.
Click … File > Preview in Google Earth
|George Knowles||3/22/11 8:28 PM|
|George Knowles||3/23/11 12:03 PM|
I updated the model to better illustrate the process of creating the grid.
Download SketchUp Model — Wing Beach, Saipan with 50 Meter Grid Oriented N-S
|johnfraser1||3/25/11 4:21 PM|
Thanks that's a lot of work you've done. i'll try it again using those instructions.
btw, i don't find your SketchUp Model — "Wing Beach, Saipan with 50 Meter Grid Oriented N-S" when i click on the link above.
the link takes me to Google Documents where it says: "Sorry, the page (or document) you have requested is not available" .
the Google Documents page does have a Documents header, but when i click on that header, the 50m grid is not on the list. your previous 25m grid is still there however.
|George Knowles||3/25/11 5:05 PM|
There is only one Wing Beach Saipan.skp file in the list of documents.
Btw, how’s the weather in Saipan?