Questions tagged [m-values]
The m-values tag has no usage guidance.
32 questions
2
votes
2
answers
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Calculating M-values in specific coordinate system ArcGIS Pro
I have an issue with calculating M-values in ArcGIS Pro: I need to calculate them in a specific coordinate system.
For example, the M-coordinate of a first vertex is set to 0; next should be 0 + the ...
- 21
2
votes
0
answers
52
views
Generating cumulative M-values in QGIS
I have a linear dataset in QGIS each vertex in each line has an X, Y and Z values. I want them to have M values. There is a set M value tool but it only seems to set a single value to each vertex i.e. ...
- 21
3
votes
1
answer
110
views
Transforming an sf feature without M-values into one with M-values
Basic question
Working with the sf library in R, how can I add M-values to a geometry that doesn't already have them?
Or put differently, given an sf feature without M-values, how can I create a new ...
- 2,749
2
votes
1
answer
350
views
Symbolizing line thickness by M-values
Is there a possibility in QGIS 3 to render line thickness by M values on every vertex?
The new Interpolated Line symbol layer type introduced in version 3.20 seems suitable for the task, but so far ...
- 308
2
votes
2
answers
341
views
How to request GeoJSON standard be enhanced to support M-values
As far as I can tell, the GeoJSON standard doesn't support the M-dimension of linear referencing lines.
For example, Oracle Spatial doesn't support LRS lines when using the SDO_UTIL.TO_GEOJSON() ...
- 1,272
1
vote
1
answer
801
views
LRS SDO_GEOMETRY to "LINESTRING M" WKT format
I have a query that produces an LRS SDO_GEOMETRY as WKT (Oracle 18c):
select
SDO_UTIL.TO_WKTGEOMETRY(SDO_LRS.CONVERT_TO_LRS_GEOM(sdo_geometry('LINESTRING(1 2,3 4)')))
from
dual
Output:
...
- 1,272
4
votes
1
answer
479
views
PostGIS ST_Intersection with interpolated M value
I have a polygon and a GPS Trace (incl timestamps in the M dimension) zig-zagging across the polygon.
I want to find the time intervals whenever the GPS trace entered and exited the polygon, which can ...
- 83
0
votes
1
answer
435
views
Use M Value with POLYLINE.segmentAlongLine
Currently I have a table with Begin and End M measurements. I also have a route feature class. I would like to be able to use the POLYLINE.segmentAlongLine(start_measure, end_measure) method but ...
- 83
1
vote
1
answer
220
views
Set M-values as distance: Multipart M-values are set in descending order
I have a multipart polyline in an ArcGIS Pro 2.9.2 FGDB feature class (NAD83 UTM):
I can set the M-values to the cumulative distance of the line by using the Set As Distance tool (setting "...
- 1,272
1
vote
1
answer
585
views
Set M-values to cumulative length of line (via ArcPy)
ArcMap 10.7.1 — Oracle 18c EGDB — SDE.ST_GEOMETRY
I have existing SDE.ST_GEOMETRY polylines that have M-values (aka 'measure values' for linear referencing purposes).
I want to update the M-values ...
- 1,272
1
vote
2
answers
2k
views
How to convert from OGR geometries (with M-values) to shapely geometries (without M-values)?
Main question
Suppose I have a few OGR geometries, all of them containing M-values.
Is there a generic solution that allows me to translate them to Shapely geometries without M-values?
Shapely and M-...
- 2,749
1
vote
0
answers
325
views
Remove M value & Z value from shapefile JavaScript [closed]
Is there a way to remove the m value and the z value from a shapefile using JavaScript "leafletjs & shpjs”?
- 139
2
votes
1
answer
567
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Save GNSS accuracy for each vertex of polygon/line feature in QField
In QField it is possible to save positioning information in point features through expression variables like @position_horizontal_accuracy or @position_number_of_used_satellites. The explanation is ...
- 23
3
votes
2
answers
771
views
Auto-recalculating M-values using ArcPy in ArcGIS Pro
I have M-enabled polylines, these lines are calibrated using different calibration points and some even start from zero. I want to drop existing M-values and then want to assign distance as M-value.
I ...
- 428
1
vote
1
answer
265
views
Shapefile to PostGIS using FME - Column has M dimension, geometry does not
I'm trying to insert a shapefile into PostGIS using FME but I always get an error saying:
ERROR: Column has M dimention but geometry does not
CONTEXT: PL/pgSQL function debug.trig_fonc_force_geom_3d() ...
- 155
12
votes
2
answers
6k
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Understanding the concept of m value
As far as I understand, the m value "is a measured distance along a route" (similar answers here), thus similar to the mileage of a car driving over a highway. The m value defines the point ...
- 74.9k
1
vote
0
answers
240
views
Adding M values to a shapefile so the distance along the line is displayed as a derived attribute in QGIS
I'm new to QGIS which I'm using to create data for a road network. I have a road network setup as a polyline shapefile, but need to identify the chainage long the network sections to use in other ...
- 11
0
votes
1
answer
152
views
Creating lines along calibrated polyline from M values in ArcMap
I have an M-value enabled polyline feature class and from-to M-values of lines.
The polyline is already calibrated.
Is there any way to create line along the calibrated polylines or get that segment ...
- 428
2
votes
0
answers
82
views
Creating multipoints from points and setting incrementing M value in spatialite
I have a layer of points, which I want to group into multipoints grouping by some column. This part is easy:
SELECT name_pre, CastToMulti(GUnion(geometry)) AS geometry
FROM sp_survey
GROUP BY ...
- 21
2
votes
1
answer
415
views
Read M value (CoordinateXYZM) from shapefile with geotools
After successfully writing M values into a shapefile (.shp, only points for now), I now also want to read the generated file and print the full coordinate set (x, y, z and m) using geotools (23-...
- 291
4
votes
2
answers
496
views
Pasting point data into PostGIS with M Values
I have point data exported from Trimble Insphere as .shp. I am trying to paste the data into our PostGIS database but keep getting:
PostGIS error while adding features: ERROR: Column has M dimension ...
- 43
3
votes
1
answer
445
views
Write M value into shapefile with geotools
I'm using the Java 1.8 library geotools (version "23-SNAPSHOT") to generate a shapefile.
Opening the resulting .shp file with QGIS was successfull and I noticed that the gemeotry was apparently ...
- 291
1
vote
0
answers
2k
views
View M value in QGIS
I've got a ".shp" file (plus the additional .dbf, .fix, .prj, .shx files) that was created using the geotools library and want to view its data using QGIS 3.8.2.
QGIS properly displays all of the ...
- 291
1
vote
1
answer
943
views
Cannot solely remove M value of Shapefiles
I have a couple of Shapefiles which are of geometry type ZM (like PolygonZM, MultiLineStringZM, etc.), however my database (a PostGIS database) is of geometry type Z (like PolygonZ, MultiPointZ, etc.)....
- 279
1
vote
0
answers
112
views
Calibrate routes not lining up with calibration points [closed]
I am currently building a model that calibrates Z and M values from Cross Sections for a stream. Z being the 100yr flood and M being the station number. What's happening is the vertex on the stream ...
- 39
17
votes
3
answers
16k
views
What does M-value represent?
I am trying to wrap my ahead around the meaning of the M-value.
I read ESRI's dictionary definition here: https://support.esri.com/en/other-resources/gis-dictionary/term/m-value
and was not able to ...
- 2,141
2
votes
1
answer
609
views
Assigning attributes values to PointZM and convert to LineZM Geometries in QGIS? [closed]
I have elevation and measured values in attribute table of points layer.
Is there a way to convert this layer into PointZM (with elevation and measured) and assign elevation and measured values to ...
- 79
4
votes
1
answer
499
views
Recover M-values from PostGIS `ST_Intersection`?
I am querying the intersection of a path (LinestringZM) through a region (MultiPolygon) but the ST_Intersection returns only the Lat/Long/Alt coordinates and I need to recover time, stored in the M ...
- 113
2
votes
1
answer
163
views
Determining distance on line of point, given measure?
I need to determine into a standalone python script the distance of a point on a polyline with M-values and its' coordinates, at a specific measure.
For example, I have to calculate the X,Y of a ...
- 161
12
votes
2
answers
4k
views
Extracting nodes with M-values for Linear referencing in QGIS
I have a MultiLineStringZM layer in an SQLite database, and I'm trying to visualize the measures or m-values at the vertexes. I've tried looking up information on how to do this in QGIS, and all I've ...
- 1,612
1
vote
2
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519
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Where can I find some Sample Data for Linear Referencing?
I'm teaching GIS at a Local college, and one of the classes is on Linear Referencing, specifically of Roads.
For the Practical classes, I need some Sample Data for Linear Referencing. Ideally, this ...
- 41.6k
8
votes
2
answers
3k
views
Drop M values from MULTIPOLYGON with PostGIS?
The title is self-explanatory. I wonder if there is a simple function like ST_Force2D for the M values?
- 258