Questions tagged [m-values]

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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 ...
Albine Pro's user avatar
2 votes
2 answers
199 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() ...
User1974's user avatar
  • 1,114
1 vote
1 answer
462 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: ...
User1974's user avatar
  • 1,114
4 votes
1 answer
257 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 ...
Christoph's user avatar
0 votes
1 answer
277 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 ...
kShort's user avatar
  • 123
1 vote
1 answer
141 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 "...
User1974's user avatar
  • 1,114
1 vote
1 answer
389 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 ...
User1974's user avatar
  • 1,114
1 vote
2 answers
935 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-...
Felipe D.'s user avatar
  • 2,251
1 vote
0 answers
241 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”?
Salah ED's user avatar
  • 139
2 votes
1 answer
402 views

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 ...
rob1's user avatar
  • 23
3 votes
2 answers
491 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 ...
Ayaz49's user avatar
  • 428
1 vote
1 answer
190 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() ...
BTL's user avatar
  • 155
11 votes
2 answers
3k views

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 ...
Babel's user avatar
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1 vote
0 answers
162 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 ...
Mat Thomas's user avatar
0 votes
1 answer
121 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 ...
Ayaz49's user avatar
  • 428
2 votes
0 answers
58 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 ...
Darek Bobak's user avatar
2 votes
1 answer
337 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-...
Neph's user avatar
  • 235
4 votes
2 answers
459 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 ...
Jamie C's user avatar
  • 43
3 votes
1 answer
330 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 ...
Neph's user avatar
  • 235
1 vote
0 answers
1k 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 ...
Neph's user avatar
  • 235
1 vote
1 answer
719 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.)....
Aurus Huang's user avatar
1 vote
0 answers
98 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 ...
Mellema's user avatar
  • 39
14 votes
3 answers
13k 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 ...
NULL.Dude's user avatar
  • 2,111
2 votes
1 answer
561 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 ...
Mohsin's user avatar
  • 79
4 votes
1 answer
438 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 ...
sventechie's user avatar
2 votes
1 answer
155 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 ...
panda's user avatar
  • 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 ...
TJ Rockefeller's user avatar
1 vote
2 answers
448 views

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 ...
Devdatta Tengshe's user avatar
6 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?
picardo's user avatar
  • 238