Georeferencing Imagery Discussion — Global Mapper Forum

How to add an image without deforming it? (Preserve Scaling)

XionicFire — Wed, 24 Jul 2024 19:26:51 +0000

Hello all

So this is something that has nagged me for a long time, I've so far avoided it but this new customer NEEDS this data to be as accurate as possible, he has paper scans of the borders of his land but has no way to digitize them properly other than a super accurate high resolution scan (which we already did)

From what I've seen on the south part of the land, borders do match somewhat the terrain (streets, fences etc) but not on all the land, the part up north where its mostly forest there's no way to georeference it in any acceptable way.

I know global mapper can add an image and I can manually rectify/georeference it, we've tried doing this, but this warps and deforms the image to match the points, and sometimes far away parts of the image get super warped.

So the question is this:

Is there a way to just add the image to the map without messing with it/warping it in any way, just add it , even if its tiny, so I can then re-scale it/rotate it (all of it as one unit) using the GM existing tools until I can make the lines sort of fit with the existing roads on the south part so that way the north part is as accurate as possible?

After this I can then draw on top of the image the polygon, with as much detail as I can to match it as best as possible.

The workaround I've been currently using is exporting the terrain from GM as a Geotiff, then opening it on Adobe Illustrator, open the map image, overlaying it over the first one, rescale/rotating it until it matches, then drawing lines on top of the original Exported GM image, saving it, opening it on GM, re draw the lines I drew as vector and "sorta" get a decent accurate line map.

It works but its absurdly time consuming, there has to be a better way, can GM do something like this? it looks like it can but i cannot find out how, searched forums but nothing related came up.

I've tested the option of insert image at origin point instead of rectify, but when I click on zoom to layer it does nothing, zooming out to the galaxy and selecting everything also does not detect any items, and manually rectifying it warps it.

So I'm stumped, any help would be super appreciated

Thanks in advance

How to perform an affine transformation to a raster layer

corellana — Thu, 23 May 2024 14:11:08 +0000

Hi All,

I need to perform an affine transformation to a raster dem. To do this I have two control points with coordinates in two different systems. I tried with the "SHIFT - Transform Coordinates Based on File, but I'm not getting the expected results

Thanks in advance!

Criss

Absolute Deviation

GeorgeM7 — Wed, 22 May 2024 07:41:55 +0000

I am trying to follow these steps to check my absolute deviation/accuracy checks of my layers and the control points of the site.

However, I am presented with this when I try create the control points.

Any idea on how to help/fix this or any other ways of checking accuracy/absolute deviation?

Quick note - ChatGPT is a great tool for learning things!

Does adding reflective tape to GCPs make them easier to see in "Color by Intensity?"

LidarDronePilot23 — Wed, 08 May 2024 21:10:43 +0000

I am having a very difficult time seeing my GCPs in my point cloud when viewing by Intensity. I am wondering if adding reflective tape to them will make them easier to see?

Turning off layers in a rectified pdf

AFG — Wed, 10 Apr 2024 06:20:42 +0000

When I load an image in a pdf I get to choose what layers it imports before I manually rectify the image. Once I have loaded the pdf is it possible to turn off a layer that I left on by mistake or do I need to load the pdf again.

Thanks.

Why doesn't wheel zoom work from mouse position when rectifying image?

RonTheSurveyor — Mon, 12 Feb 2024 17:04:24 +0000

I have a user in my office who is running the same version of GM but for some reason his mouse zoom tool always zooms into the center of the image. It ignores the position of the mouse pointer. This only happens when picking control points while rectifying an imported image. On the main map view, the wheel zoom works as expected.

Select geotagged jpg images on map (in folder)

mcweb — Thu, 27 Oct 2022 16:55:15 +0000

Hello!

I have 1500± geotagged drone jpgs, loaded into GM as the camera icon with orientaion.

Is there any way to window select those images and have them be selected in the folder from which they were loaded?

Thanks!

points with photo exif data on the correct positions

WH1961 — Thu, 13 Oct 2022 13:12:33 +0000

when I make photos with the handy in the EXIF data the GPS location is saved.

I want to get points on the photo locations with the EXIF data (at least the photo file name).

Is this possible in Global Mapper 23.1 Standard?

Modis Sinusoidal in GM

oscillation — Thu, 22 Sep 2022 21:07:29 +0000

Hi. GM has the ability to ingest various MODIS Sinusoidal projected products. Can anyone comment on projecting this to another projection, let say geographic wgs84 for simplicities sake. Will GM do that projection properly, or would a transform like that not be recommended in GM? Thanks

Raster Rotation

tikhpetr — Tue, 09 Aug 2022 18:50:58 +0000

Hi!

I have a georeferenced raster. How do I rotate it relative to the bounding polygon's cenroid?

Thanks!

Georeferencing an image with a single co-ordinate

NEV — Sat, 06 Aug 2022 01:26:02 +0000

I have 30 vertical aerial photographs with an exact co-ordinated of the centre point of each. Can I display them using this co-ordinate only?

How to convert Sat image/geo ref data into raw raster (ASRP/CRP etc) data

Ben855 — Wed, 06 Jul 2022 14:10:40 +0000

I am trying to import sat imagery into an aviation planning system however it doesn't behave well with standard sat formats like Geotiff etc. Can I convert sat imagery or geo-referenced imagery into a raw raster format that I can then manipulate as I know the Aircraft will read ASRP, CRP, CADRG data without any problem. Any help would be greatly appreciated.

Export Geo Ref image as Raster

Ben855 — Thu, 05 May 2022 10:05:31 +0000

Hi, how do I define what scale is set when I geo reference an image and want it to be exported in ASRP/CRP/CADRG format. I have some imagery that I want to export as 25K Raster. Any help would be greatly appreciated.

Incorrect map-file?

tikhpetr — Sun, 26 Dec 2021 16:20:58 +0000

Hi! GM 22.0

A friend asked to reproject a fragment OSM. EPSG 4326 to 3334(G-K Z4). For its tasks it is necessary .map-file. I did the job and decided to open the result in GM and got :

https://disk.yandex.ru/d/KDcZPuy-2PRwKA

Tagging image polygons with exif date and time of day

garnetwhyte — Fri, 10 Sep 2021 10:46:52 +0000

Good morning, I'm trying to figure out a way to extract the exif data of source photos.

I've already created polygons of photo extents, but can't figure out how to get the exif data from the associated photos into a shp file.

Mirror/ Flip Imagery?

Eric123 — Tue, 31 Aug 2021 15:03:06 +0000

Is it possible to copy and mirror/flip an imagery? Can this also be done with features points?

Export a PDF image georeferenced

AurioFrancisco — Fri, 28 May 2021 14:08:14 +0000

Hi all,

I have an georeferenced RGB image and would like to export it as a pdf with it's geo information, so that I can use it on Avenza maps. Any idea of how I can do this?
Thank you in advance for reading.

Regards,
Aurio

Large frame camera imagery import

Peter_GURS — Thu, 21 Jan 2021 11:55:13 +0000

I have large format professional aerial cameras imagery (Vexel Ultracam) with absolute orientation (x, y, u, omega, phi, kapa). How can I import and geolocate that imagery to GlobalMapper? Can I use PixelToPoints function to calculate DSM?

Image Export "to selected boundary" - But not really?

MFurrer — Wed, 28 Oct 2020 22:09:19 +0000

Am I missing something? When I have an image loaded & export the image cropped to *any* boundary (I use amoebas, grids, etc.), the resultant image is rectangular when viewed in anything other than GM. I don't recall always having this issue.

A majority of my work in this regard is receiving anywhere from 5-100 miles of georeferenced corridor imagery. I then break it into more manageable image chunks (1 mile to 5 miles for instance) along the corridor. Resultant images are then loaded into Civil3d. I can't get those images to NOT be an absolute mess. If I bound the export to an aligned grid along the corridor, it makes a ridiculous overlap mess. Option B is cardinal aligned grid to export to, but then I end up with 3x the images necessary to cover the corridor.

Am I missing some crucial part of the workflow somehow? Also ~ side note...I can't get Civil3d to load any GM exported imagery with transparent background. Attempting to re-assign transparent pixels in C3D crashes the software.

Layer shifting a fixed distance

Seti — Sun, 14 Jun 2020 13:04:13 +0000

When the default image coordinates of an image is not accurate enough, the "Layer shifting a fixed distance" function is extremely useful. Sometimes, however, it seems not to work properly, and it also changes the projection. This is illustrated below with an ASTER image, which I have in ENVI format. The first image (in red) is to be moved 70 m east and 15 m south so that it pefectly fits the second ASTER image, below.

But when I am shifting it by any distance in meters, either by specifying offset "as fixed X/Y distance offsets" or "as distance and bearing", the whole image is reprojected, as you can see below:

Looking at the layer projection tab, the projection was not modified.
I could not figure out what is the logics behind this behaviour...

GM does not save coordinate system parameters

tikhpetr — Tue, 25 Feb 2020 07:57:08 +0000

Hi!
I have a raster in Pulkovo 1942 / Gauss-Kruger zone 7(EPSG 28407). After checking georeferencing, i am set the coordinate system Pulkovo 1995 / Gauss-Kruger zone 7(EPSG 20007) and export to a new raster. But the new raster, when I open it, for some reason has the same coordinate system (28407). How to win this?))
GM20.1
If interested, the source raster is here: https://yadi.sk/i/uWI2dGtz8la9Dw
Thanks!

Import PDF as raster layers

sphillips — Fri, 25 Jan 2019 13:01:43 +0000

When importing a PDF as a raster image with 'Import each PDF layer to a separate GM Layer' I am only shown a single layer and prompted to rectify it. If I rectify the layer I am then prompted to rectify every single layer individually and I have no option to cancel. My PDF contains 103 layers so this is not practical and I have to use the Task Manager to exit GM.

Why do we need to rectify each layer of a PDF individually?

A tough map

Alpamayo — Fri, 02 Aug 2019 19:24:28 +0000

Hi. I found online this map and, for the first time, I'm having a real hard time in trying to georeference it. Is it me or there is something wrong with such map?
In general I use the utm grid and with OziExplorer I manage to solve the problem. This time though the georeferencing is completely off. What do you think?
Thanks
Mike

Adding Coordinate Attributes to Point Features

Doc2r — Wed, 03 Jul 2019 10:36:45 +0000

Bob,
Is it possible to script this function?

HELLENIC POSITIONING SYSTEM (HEPOS)

arigo — Tue, 18 Jun 2019 10:30:33 +0000

Does anybody have a .prj file for HEPOS? I found the following, but does not seem to work.

PROJCS["Greek_HTRS07_TM07",GEOGCS["GCS_HTRS07",DATUM["D_HTRS07",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",500000.0],PARAMETER["False_Northing",-2000000.0],PARAMETER["Central_Meridian",24.0],PARAMETER["Scale_Factor",0.9996],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]]

Thanks in advance.

Using Check shot GCPs

dpitman — Sat, 20 Apr 2019 12:37:10 +0000

Hi Folks,

I don't yet have GM.

In GM, how do you examine the coordinates of check shots to compare them to surveyed values?

Thank you,
Dave

georeferenced image coordinate boundaries

John N — Mon, 30 Sep 2013 14:36:58 +0000

I have been using GM12 to georeference vertical sections (as opposed to plan maps) and generate geotiffs therefrom. The purpose of this is to "hang" these sections in 3-D space in Rockworks. The utility Rockworks uses requires the real world coordinates of the corners of the geotiff image. I thought I was getting this information by clicking on the VIEW tab and selecting "PROPERTIES". This generated coordinates that could be exported to the clipboard, which I did.

After compiling these cross-sections, I found that they appeared stretched vertically, and data that I superimposed on them supported this observation. At first I thought it had to do with the Projections setting, assuming that GM could only handle plan maps. This did not seem to be an issue except the image in GM was noted as being out of bounds and produced a bar scale that was many times larger than reality. I subsequently found that by using the Orthographic projection, this problem was solved, however, I was still getting stretched geotiffs.

Further investigations revealed that the coordinates generated with the VIEW and PROPERTIES routine, mentioned above, yielded the coordinates of the interior of the screen and not of the image file...Huh?? I am struggling to figure out what the purpose in that is, but there may be a reasonable explanation.

Nonetheless, I would like to know if there is a routine in GM whereby I can get the coordinate information of the georeferenced image. I have been working around this by importing the geotiff file into my CADD program and determining the image boundaries that way, but this is an extra step I would like to avoid.

Thanks in advance.

Can UAV Image processed without GCP provide accurate tree height calculated from CHM?

mahmudmamoon — Fri, 21 Dec 2018 21:13:35 +0000

I have collected UAV images from the field. But I did not use GCP marker. Actually, I need to measure tree height and Crown Projection Area from the forest area. I don't need to prapare any mapping. So, without using GCP, can I get accurate tree height from CHM?

Image Rectification

Nakela — Mon, 29 Oct 2018 09:19:21 +0000

Hi there,

I am rectifying a Google Earth image in Global Mapper v18. I add in my Ground Control Points and then my image, and proceed to matching up the points. When I save the rectified image as a GeoTiff however and open it in ArcMap v10.4.1, the following notification pops up:

"One or more of the added layers has an extent that is not consistent with the associated spatial reference information.

Re-projecting the data in such a layer may lead to unexpected behavior. Use ArcCatalog to confirm the spatial reference is correct and adjust if necessary."

When I open up the layer properties of the GeoTiff in Arcmap, it seems as though the extent of the raster has changed during the export. The extent of the top, bottom, left and right are in the thousands, instead of between -180 to 180 (longitude) and -90 to 90 (latitude).

How I can correct this? Please help.

Thanks.

GeoReferenced an Image in ArcGIS and it will NOT read properly into Global Mapper?

jcojred — Fri, 22 Jun 2018 15:41:58 +0000

I have an image from a publication that was geo-referenced using Lat/Long WGS84 (like I have done a hundred times before in ArcGIS). I was sharing that georeferenced image with a colleague who was using Global Mapper (older version ~11.2) and none of the images properly located themselves (supposed to be offshore Peru and they are all ending up offshore Ghana and Nigeria). It seems that global mapper would not read the .tfwx and .aux.xml correctly. No idea why? The version could be too old. I have noticed on other GIS programs as well for example QGIS also does not ready the location correctly and also places the ArcGIS image in West Africa instead of South America.

Has anyone else experienced problems sharing Georeferenced images from ArcGIS to global mapper or any other GIS programs?

Standard Geo-Referencing.

Blank ArcGIS .mxd v10.4
Setup lat/long graticules for the reference frame to match the image and pick the points
Use the default of the 1st order polynomial affine and it fits perfectly everytime in ArcGIS in any version.

Screen capture example in Global Mapper