GPS and Aerial Georeferencing

[Anonymous]

I am new to Autodesk Map and need to learn how to bring GPS points in and lay them over an aerial. Problem is I don't know how to bring in an aerial and georeference it. (i.e. does it have to be from a specific source, brought in through a specific path, file format, etc.)

[Anonymous]

If your image has correlation data (geotiff or associated world file, etc), then Map will georeference it automatically. Simply insert the image into a drawing using the Map Image Insert tool, (you likely can accept all the defaults in the dialogues). If it is not georeferenced, you will need to reference it manually, which would likely require image editing software such as Raster Design. As for your GPS data, I would suggest that you convert it to a comma delimited ASCII file in Northing, Easting, Elevation, and description format and import it into Map (assuming you have Map 3D). If you do not have Map3D, then you will need software that can convert the points into a DXF or make a drawing for you, as Map does not have the capability to import Points from text files. It can import shape files, so if you have ArcView you could create a shape file from your points and import the shape file. Keep in mind that the image and the GPS data may be in different coordinate systems. If so, you will have to transform the image and/or the points into a common system. This can be done using a transformation query after you have the data in DWG format. You can read about transformation queries in the help system and post additional questions as needed. "ibisalyson" wrote in message news:13131856.1096980109032.JavaMail.jive@jiveforum2.autodesk.com... >I am new to Autodesk Map and need to learn how to bring GPS points in and >lay them over an aerial. Problem is I don't know how to bring in an aerial >and georeference it. (i.e. does it have to be from a specific source, >brought in through a specific path, file format, etc.)

[Anonymous]

"Neil W" wrote in message news:4162a375$1_1@newsprd01... > As for your GPS data, I would suggest that you convert it to a comma > delimited ASCII file in Northing, Easting, Elevation, and description format > and import it into Map (assuming you have Map 3D). If you do not have Map3D, > then you will need software that can convert the points into a DXF or make a > drawing for you, as Map does not have the capability to import Points from > text files. It can import shape files, so if you have ArcView you could > create a shape file from your points and import the shape file. This step is fairly easy to accomplish via lisp or vba. A web search would probably yield an acceptable tool within a few minutes.

[Anonymous]

When you say Northing and Easting, I assume you are referring to state plane coordinate systems? I do not have Map 3D, just Map 5. I use Pathfinder Office for my GPS data which allows me to convert from lat/long to state plane and export as either a Shape File with or without blocks, or an AutoCAD DXF Setup with or without blocks. I've been exporting them as .dxf with blocks and opening the file in Map. It generally comes up as a giant blob of targets, but still has attributes attached. If I change the line thickness the targets minimize and you can start to see the shape of the points. That's about as far as I have been able to get.
So, if I make sure my aerial is in the same coordinates as my GPS data, I should be able to insert it into the drawing and then bring in the GPS points and it will automatically line up, or I have to place it manually in the drawing?

[Anonymous]

Northings and eastings are simply coordinates relative to the origin used in mapping coordinate conventions. A Northing coordinate would correspond to a Y coordinate in the cartesian coordinate system, and an Easting coordinate would correspond to the X axis of the cartesian system. Northings and eastings are independent of any particular coordinate system (ie..state plane), so you will need to know what coordinate system you are using to export your data. If your photo is georeferenced, you would want to export your GPS data to the same coordinate system as the photo. Then the data will align with the photo when you combine them in Map. I would guess that your text height settings for your DXF export are too large which causes the point attributes (labels) to show exccessively large in autocad. See if you have any control over how the text displays in your Pathfinder export settings. I would recommend exporting your points data to a shape file and importing it into Map. This will allow you to have more control over how the points are displayed in Autocad. You will need to learn how to import data from Shape Files, particularly about importing the attributes of your points as object data and using a block to represent the points. "ibisalyson" wrote in message news:27285725.1097005058459.JavaMail.jive@jiveforum1.autodesk.com... > When you say Northing and Easting, I assume you are referring to state > plane coordinate systems? I do not have Map 3D, just Map 5. I use > Pathfinder Office for my GPS data which allows me to convert from lat/long > to state plane and export as either a Shape File with or without blocks, > or an AutoCAD DXF Setup with or without blocks. I've been exporting them > as .dxf with blocks and opening the file in Map. It generally comes up as > a giant blob of targets, but still has attributes attached. If I change > the line thickness the targets minimize and you can start to see the shape > of the points. That's about as far as I have been able to get. > So, if I make sure my aerial is in the same coordinates as my GPS data, I > should be able to insert it into the drawing and then bring in the GPS > points and it will automatically line up, or I have to place it manually > in the drawing?

[Anonymous]

I realize after contemplating your problem with the points showing as a large "blob" in autocad that it may be due the way you have Autocad set to display points. Type DDPTYPE on the command line. This will give you access to the points display settings. You can change the display style of the points and display scale. Set the point style to anything other than a Dot or Blank, and set the display scale to an absolute value (try a value of 5 units) rather than as percent of View scale. Then perform a zoom extents and you should see your points. "ibisalyson" wrote in message news:27285725.1097005058459.JavaMail.jive@jiveforum1.autodesk.com... > When you say Northing and Easting, I assume you are referring to state > plane coordinate systems? I do not have Map 3D, just Map 5. I use > Pathfinder Office for my GPS data which allows me to convert from lat/long > to state plane and export as either a Shape File with or without blocks, > or an AutoCAD DXF Setup with or without blocks. I've been exporting them > as .dxf with blocks and opening the file in Map. It generally comes up as > a giant blob of targets, but still has attributes attached. If I change > the line thickness the targets minimize and you can start to see the shape > of the points. That's about as far as I have been able to get. > So, if I make sure my aerial is in the same coordinates as my GPS data, I > should be able to insert it into the drawing and then bring in the GPS > points and it will automatically line up, or I have to place it manually > in the drawing?

[Anonymous]

The orthophoto (aerial picture) you have should have come with a world file (typically a text file with a .tfw extension) To get the orthofile to align or be placed correctly within Autocad, ensure your UCS is set to world, then using the contents of the .tfw file (0.1 0 0 -0.1 -74.15 5669029.85) determine which values would be your easting (x=-74.15) northing (y=5669029.85), and which would be the scale factor (0.1) (autocad raster design can read the .tfw file and perform a quick insert) then using the autocad image insert command place the correct values within the dialog and away you go. I agree that the large blobs are most likely the DDPtype (points) being displayed too large..zoom in, regen should help. The points on your GPS should align with the orthophoto if things are setup correct. Within your Pathfinder Office, it has an option to load in the photo as a background file, it too will use the world file to orientate it in the correct location. "Neil W" wrote in message news:41630d3d_2@newsprd01... >I realize after contemplating your problem with the points showing as a >large "blob" in autocad that it may be due the way you have Autocad set to >display points. Type DDPTYPE on the command line. This will give you access >to the points display settings. You can change the display style of the >points and display scale. Set the point style to anything other than a Dot >or Blank, and set the display scale to an absolute value (try a value of 5 >units) rather than as percent of View scale. Then perform a zoom extents >and you should see your points. > > "ibisalyson" wrote in message > news:27285725.1097005058459.JavaMail.jive@jiveforum1.autodesk.com... >> When you say Northing and Easting, I assume you are referring to state >> plane coordinate systems? I do not have Map 3D, just Map 5. I use >> Pathfinder Office for my GPS data which allows me to convert from >> lat/long to state plane and export as either a Shape File with or without >> blocks, or an AutoCAD DXF Setup with or without blocks. I've been >> exporting them as .dxf with blocks and opening the file in Map. It >> generally comes up as a giant blob of targets, but still has attributes >> attached. If I change the line thickness the targets minimize and you >> can start to see the shape of the points. That's about as far as I have >> been able to get. >> So, if I make sure my aerial is in the same coordinates as my GPS data, I >> should be able to insert it into the drawing and then bring in the GPS >> points and it will automatically line up, or I have to place it manually >> in the drawing? > >

[Anonymous]

neil,

When i convert a Pathfinder to AutoCAD dxf it never is 1-1, i have checked all menus in AutoCAD and set all coordinates and units to match my .ssf files..is there something i am overlooking?

Thanks

[Anonymous]

Autocad does not change your data when you assign units to it. Assigning units simply tells autocad what the units represent. If you have a drawing that was created with one unit=1 foot and you later assign that drawing to use architectural units, your drawing will be out of scale by a factor of 12, because Autocad will interpret one unit=1 inch. In other words, your linework will not automatically be rescaled. Thus if your DXF is not fitting your photo, then you need to transform your drawing or you will have to change the output coordinates from pathfinder to match the coordinate system of the photo. It is crucial to understand that autocad does not perform transformations "on the fly" when you change the units or coordinate system of a drawing. If you want your data to fit your photos, the data must be on the same coordinate system as the photo, regardless of what you tell autocad it represents. Autocad CAN transform your data by means of a transformation query if you have MAP. A transformation query requires that you assign the known coordinate systems to your source drawings and attach those drawings to a new drawing that has a different coordinate system assigned to it. Then when the data is queried from the source drawings, Map will transform it to fit the coordinate system of the new drawing. Thus in your scenario, you would create a drawing for your aerial photo and insert the photo into it using the Map Image insert tool. This will place the image into the drawing in the georeferenced coordinate system that is established by the associated world file (or embedded georeferencing information if the image is a Geotiff). You will then assign that coordinate system to the drawing and save it. Next you will start a new drawing and import your DXF file into this 2nd drawing and assign the coordinate system to the drawing that corresponds to the coordinates of the DXF file. Next you would attach the 1st drawing (the one with the photo) and perform a query. Map will transform the coordinates of the photo to match to coordinate system of your DXF drawing and the data should fit properly. While this is a cludgy way to get data to fit together, it does work well once you get a feel for it. I recommend that you read the help system about Transformation queries and Image Georeferencing. "joebobway" wrote in message news:353849.1098217738912.JavaMail.jive@jiveforum2.autodesk.com... > neil, > > When i convert a Pathfinder to AutoCAD dxf it never is 1-1, i have checked > all menus in AutoCAD and set all coordinates and units to match my .ssf > files..is there something i am overlooking? > > Thanks

[Anonymous]

I'm not seeing the first few post to this thread but will suggect you check the "units" in Pathfinder Office default is Lon/Lat. (?) just taking a guess here. Murph "joebobway" wrote in message news:353849.1098217738912.JavaMail.jive@jiveforum2.autodesk.com... > neil, > > When i convert a Pathfinder to AutoCAD dxf it never is 1-1, i have checked all menus in AutoCAD and set all coordinates and units to match my .ssf files..is there something i am overlooking? > > Thanks

[Anonymous]

I'm having a problem with a bunch of sids.  I have a drawing which consists of a previously created dwg, connected raster (sids) and loaded layers (GIS features (shp) I saved as layers).  I need to change the UCS to print landscape, so there is a saved named ucs called W80S.  When I apply this UCS, everything - except the raster - flips by 80 degrees.  So I've been trying to save the sids in a new map/dwg as an sdf but I can't seem to select the images (I can select them, but they aren't recognized by the SDF exporting mechanism - it says no objects selected). 

[Murph_Map]

You need to save the Map to AutoCAD dwg format, then you can use the users UCS all you want. Why not just set up the page setup to landscape and forget about rotating anything?

[Anonymous]

Hi Murph,

Isn't the point of this MAP 3D program that it can use both drawing objects and geospatial features?  This is making me so nuts.  

But, thanks for replying.

[Anonymous]

"Isn't the point of this MAP 3D program that it can use both drawing objects and geospatial features?"

Yes, that is the point of Map 3D......... until you want to print. Then the goal of Map 3D is to give you as hard of a time possible and print 3 different ways with the same settings and leave your aerials off for no reason and only draw half your shp geometry and only Label what it thinks needs to be labeled even though you have it setup just right and if you try to hard it will just quit printing your labels all togetherand just because you put the layers in the order you think they should be in does not mean they will print in that order and you cant use polygonal viewport because things will mysteriously be left off and then if you want to print to PDF you get to start all over again.

That is one heck of a sentence if i don't say so myself.

 In short,  Good luck.